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Yu S, Ma L, Gao Y, Zheng H, Hu X, Liu R, Shi Y, Yin W. Effects of fissure length and angle on the fracture modes of 3D printed teeth model: Insights from DIC-based fracture tests and meshless numerical simulations. J Mech Behav Biomed Mater 2024; 154:106512. [PMID: 38554582 DOI: 10.1016/j.jmbbm.2024.106512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/13/2024] [Accepted: 03/19/2024] [Indexed: 04/01/2024]
Abstract
To investigate the influences of teeth fissure properties on their failure modes, 3D Printing technology is used to prepare the teeth models. The strain distributions of the teeth model surfaces at each moment of the loading processes are obtained by the DIC technique. And the progressive failure processes as well as the stress distributions of the teeth models are simulated by the improved Smoothed Particle Hydrodynamics (SPH) Method. Experimental results show that under the action of the steel ball, the teeth models mainly produce two types of cracks: The tensile cracks along the pre-existing fissures and the shear cracks along both sides of the teeth model. The existence of prefabricated fissures greatly reduces the peak strength of the teeth models. Compared with the circumstances containing no pre-existing fissures, the peak strength of d = 1 cm, d = 2 cm and d = 3 cm decreases by 22.33%, 31.79% and 18.94%, respectively, and the peak strength of θ = 30°, θ = 45°, θ = 60° decreases by 10.78%, 44.01% and 34.3%, respectively. Numerical results show that the initiations of tensile cracks are induced by the high tensile stress concentrations at the pre-existing fissure tips, while the shear cracks are caused by the high tensile stress concentrations in the low tensile stress concentration areas after the initiation of tensile cracks. The research results can provide some references for the understandings of teeth failure mechanisms as well as the applications of SPH method into teeth crack propagation simulations.
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Affiliation(s)
- Shuyang Yu
- School of Transportation and Civil Engineering, Nantong University, Nantong, 226019, China
| | - Li Ma
- Nanjing Health Information Center, Nanjing, 210003, China
| | - Yuan Gao
- School of Transportation and Civil Engineering, Nantong University, Nantong, 226019, China
| | - Hao Zheng
- Nanjing Stomatological Hospital Medical School of Nanjing University, Nanjing, 210008, China
| | - Xueying Hu
- School of Transportation and Civil Engineering, Nantong University, Nantong, 226019, China
| | - Runyu Liu
- School of Transportation and Civil Engineering, Nantong University, Nantong, 226019, China
| | - Yue Shi
- School of Transportation and Civil Engineering, Nantong University, Nantong, 226019, China
| | - Weidong Yin
- Nanjing Health Information Center, Nanjing, 210003, China.
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Yan J, Zhou T, Peng J, Wang H, Jiang L, Cheng Q. Sustainable liquid metal-induced conductive nacre. Sci Bull (Beijing) 2024; 69:913-921. [PMID: 38320895 DOI: 10.1016/j.scib.2024.01.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 12/01/2023] [Accepted: 01/18/2024] [Indexed: 02/08/2024]
Abstract
Nacre has inspired research to fabricate tough bulk composites for practical applications using inorganic nanomaterials as building blocks. However, with the considerable pressure to reduce global carbon emissions, preparing nacre-inspired composites remains a significant challenge using more economical and environmentally friendly building blocks. Here we demonstrate tough and conductive nacre by assembling aragonite platelets exfoliated from natural nacre, with liquid metal and sodium alginate used as the "mortar". The formation of GaOC coordination bonding between the gallium ions and sodium alginate molecules reduces the voids and improves compactness. The resultant conductive nacre exhibits much higher mechanical properties than natural nacre. It also shows excellent impact resistance attributed to the synergistic strengthening and toughening fracture mechanisms induced by liquid metal and sodium alginate. Furthermore, our conductive nacre exhibits exceptional self-monitoring sensitivity for maintaining structural integrity. The proposed strategy provides a novel avenue for turning natural nacre into a valuable green composite.
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Affiliation(s)
- Jia Yan
- School of Chemistry, Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, Beihang University, Beijing 100191, China; School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China
| | - Tianzhu Zhou
- School of Chemistry, Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, Beihang University, Beijing 100191, China; School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China
| | - Jingsong Peng
- School of Chemistry, Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, Beihang University, Beijing 100191, China
| | - Huagao Wang
- School of Chemistry, Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, Beihang University, Beijing 100191, China; School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China
| | - Lei Jiang
- School of Chemistry, Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, Beihang University, Beijing 100191, China; School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China; Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Qunfeng Cheng
- School of Chemistry, Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, Beihang University, Beijing 100191, China; School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China; Institute of Energy Materials Science (IEMS), University of Shanghai for Science and Technology, Shanghai 200093, China.
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Wang J, Ishimoto T, Matsuzaka T, Matsugaki A, Ozasa R, Matsumoto T, Hayashi M, Kim HS, Nakano T. Adaptive enhancement of apatite crystal orientation and Young's modulus under elevated load in rat ulnar cortical bone. Bone 2024; 181:117024. [PMID: 38266952 DOI: 10.1016/j.bone.2024.117024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/02/2024] [Accepted: 01/19/2024] [Indexed: 01/26/2024]
Abstract
Functional adaptation refers to the active modification of bone structure according to the mechanical loads applied daily to maintain its mechanical integrity and adapt to the environment. Functional adaptation relates to bone mass, bone mineral density (BMD), and bone morphology (e.g., trabecular bone architecture). In this study, we discovered for the first time that another form of bone functional adaptation of a cortical bone involves a change in bone quality determined by the preferential orientation of apatite nano-crystallite, a key component of the bone. An in vivo rat ulnar axial loading model was adopted, to which a 3-15 N compressive load was applied, resulting in approximately 440-3200 μɛ of compression in the bone surface. In the loaded ulnae, the degree of preferential apatite c-axis orientation along the ulnar long axis increased in a dose-dependent manner up to 13 N, whereas the increase in BMD was not dose-dependent. The Young's modulus along the same direction was enhanced as a function of the degree of apatite orientation. This finding indicates that bone has a mechanism that modifies the directionality (anisotropy) of its microstructure, strengthening itself specifically in the loaded direction. BMD, a scalar quantity, does not allow for load-direction-specific strengthening. Functional adaptation through changes in apatite orientation is an excellent strategy for bones to efficiently change their strength in response to external loading, which is mostly anisotropic.
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Affiliation(s)
- Jun Wang
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Division of Material Science and Engineering, Zhengzhou University, 100 Science Avenue, Zhengzhou, Henan 450001, China.
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Aluminium Research Center, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
| | - Tadaaki Matsuzaka
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Aira Matsugaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Ryosuke Ozasa
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Takuya Matsumoto
- Department of Biomaterials, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
| | - Mikako Hayashi
- Department of Restorative Dentistry and Endodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Hyoung Seop Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, South Korea.
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Marques JA, Falacho RI, Santos JM, Ramos JC, Palma PJ. Effects of endodontic irrigation solutions on structural, chemical, and mechanical properties of coronal dentin: A scoping review. J ESTHET RESTOR DENT 2024; 36:606-619. [PMID: 37698359 DOI: 10.1111/jerd.13135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/13/2023]
Abstract
OBJECTIVE This review aims to assess structural, chemical, and mechanical properties of coronal dentin after endodontic irrigation. MATERIALS AND METHODS Reporting followed the PRISMA extension for scoping reviews. An electronic search was carried out in PubMed, Embase, and Cochrane Library. Records filtered by language and published up to November 4, 2022 were independently screened by two researchers. Studies evaluating structural, chemical, or mechanical properties of human permanent coronal dentin after irrigation within the scope of nonsurgical root canal treatment were included. Data were extracted regarding study type, sample description and size, experimental groups, outcome, evaluation method, and main findings. RESULTS From the initial 1916 studies, and by adding 2 cross-references, 11 in vitro studies were included. Seven studies provide ultrastructural and/or chemical characterization, and six assessed microhardness and/or flexural strength. One percent to 8% sodium hypochlorite (NaOCl) and 1%-17% ethylenediaminetetraacetic acid (EDTA) were the most commonly tested solutions, with contact times of 2-240 min (NaOCl) and 1-1440 min (EDTA) being evaluated. CONCLUSIONS Overall, the literature is consensual regarding the inevitable impact of NaOCl and chelating agents on coronal dentin, with both deproteinizing and decalcifying effects being concentration- and time-dependent. The alteration of mechanical parameters further confirmed the surface and subsurface ultrastructural and chemical changes. CLINICAL SIGNIFICANCE Endodontic treatment success highly depends on restorative sealing. Understanding the result of exposing coronal dentin, the main substrate for bonding, to irrigants' action is crucial. The deproteinizing and decalcifying effects of NaOCl and chelating agents are both concentration- and time-dependent, causing surface and subsurface ultrastructural, chemical, and mechanical alterations.
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Affiliation(s)
- Joana A Marques
- Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rui I Falacho
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Institute of Oral Implantology and Prosthodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - João Miguel Santos
- Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Coimbra Institute for Clinical and Biomedical Research (iCBR) and Center of Investigation on Environment Genetics and Oncobiology (CIMAGO), Faculty of Medicine and Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
| | - João Carlos Ramos
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Institute of Operative Dentistry, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Paulo J Palma
- Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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PradeepKumar AR, JothiLatha S, Durvasulu A, Muralidhar L, Vimalesh Alagu J, Shereen J, Kishen A. Impact of Type 2 Diabetes Mellitus on the Occurrence of Vertical Root Fracture: A Case Control Study. J Endod 2024; 50:450-455.e1. [PMID: 38272442 DOI: 10.1016/j.joen.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 01/06/2024] [Accepted: 01/13/2024] [Indexed: 01/27/2024]
Abstract
INTRODUCTION The aim of this case-control study was to examine the relationship between type 2 diabetes mellitus (DM) and the occurrence of VRFs. The crack extension, dentin sclerosis, and chemical characteristics of root dentin in teeth with VRF from patients with/without DM were also compared. METHODS One hundred and thirty-two patients diagnosed with VRF in crowned root filled posterior teeth were selected. The study was conducted in 2 parts. In Part-1: The cases were matched with control teeth (1:1) for age (±5 years), sex, tooth type, apical extent of root filling, time period after root filling to a diagnosis of VRF, presence or absence of intracanal post and abutment status. The presence or absence of type 2 DM (HbA1c > 6.5) was recorded. In Part-2: The extracted teeth with VRF from the case control study were used to evaluate the extension of VRF, presence of sclerotic dentin and isthmus using a microscopic analysis; while the levels of pentosidine, collagen cross-linking ratio and mineral-collagen ratio were determined by Fourier-transform infrared spectroscopy. The distribution of DM between cases and controls was analyzed using Pearson Chi-Square test and Odds Ratio estimated. Chemical composition data was analyzed using Mann-Whitney test. The extent of sclerotic dentin was analyzed using Pearson Chi-Square test. RESULTS When compared to patients without DM, patients with DM had 2.67 (95% CI: 1.6-4.45) folds higher odds for occurrence of VRF. Pentosidine (P = .014), collagen cross-linking ratio(P = .047), mineral-collagen ratio (P = .009) and sclerotic dentin extent (P = .0009) were significantly higher in patients with DM and VRF. CONCLUSIONS Type 2 DM was more often associated with VRFs in root canal treated teeth with crowns. Root dentin from patients with type 2 DM and VRF had higher levels of pentosidine, collagen cross-linking ratio, mineral to collagen ratio and sclerotic dentin.
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Affiliation(s)
- Angambakkam Rajasekaran PradeepKumar
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute (Deemed to be University), Chennai, India
| | - Sundaramurthy JothiLatha
- Department of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, The Tamil Nadu Dr. M.G.R. Medical University, Chennai, India
| | - Archana Durvasulu
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute (Deemed to be University), Chennai, India
| | | | - Jeffery Vimalesh Alagu
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute (Deemed to be University), Chennai, India
| | - Judith Shereen
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute (Deemed to be University), Chennai, India
| | - Anil Kishen
- Faculty of Dentistry, Toronto, Canada; Department of Dentistry, Mount Sinai Hospital, Sinai Health System, Toronto, Canada.
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Álvarez S, Morales J, Tiozzo-Lyon P, Berrios P, Barraza V, Simpson K, Ravasio A, Monforte Vila X, Teuschl-Woller A, Schuh CMAP, Aguayo S. Microfabrication-based engineering of biomimetic dentin-like constructs to simulate dental aging. LAB ON A CHIP 2024; 24:1648-1657. [PMID: 38291999 DOI: 10.1039/d3lc00761h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Human dentin is a highly organized dental tissue displaying a complex microarchitecture consisting of micrometer-sized tubules encased in a mineralized type-I collagen matrix. As such, it serves as an important substrate for the adhesion of microbial colonizers and oral biofilm formation in the context of dental caries disease, including root caries in the elderly. Despite this issue, there remains a current lack of effective biomimetic in vitro dentin models that facilitate the study of oral microbial adhesion by considering the surface architecture at the micro- and nanoscales. Therefore, the aim of this study was to develop a novel in vitro microfabricated biomimetic dentin surface that simulates the complex surface microarchitecture of exposed dentin. For this, a combination of soft lithography microfabrication and biomaterial science approaches were employed to construct a micropitted PDMS substrate functionalized with mineralized type-I collagen. These dentin analogs were subsequently glycated with methylglyoxal (MGO) to simulate dentin matrix aging in vitro and analyzed utilizing an interdisciplinary array of techniques including atomic force microscopy (AFM), elemental analysis, and electron microscopy. AFM force-mapping demonstrated that the nanomechanical properties of the biomimetic constructs were within the expected biological parameters, and that mineralization was mostly predominated by hydroxyapatite deposition. Finally, dual-species biofilms of Streptococcus mutans and Candida albicans were grown and characterized on the biofunctionalized PDMS microchips, demonstrating biofilm-specific morphologic characteristics and confirming the suitability of this model for the study of early biofilm formation under controlled conditions. Overall, we expect that this novel biomimetic dentin model could serve as an in vitro platform to study oral biofilm formation or dentin-biomaterial bonding in the laboratory without the need for animal or human tooth samples in the future.
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Affiliation(s)
- Simon Álvarez
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jose Morales
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Paola Tiozzo-Lyon
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Berrios
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valentina Barraza
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Kevin Simpson
- Department of Physics, Faculty of Physical and Mathematical Sciences, Universidad de Chile, Santiago, Chile
| | - Andrea Ravasio
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Xavier Monforte Vila
- Department Life Science Engineering, University of Applied Sciences Technikum Wien, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Andreas Teuschl-Woller
- Department Life Science Engineering, University of Applied Sciences Technikum Wien, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Christina M A P Schuh
- Centro de Medicina Regenerativa, Facultad de Medicina, Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - Sebastian Aguayo
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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Garizoain G, Parra RC, Aranda CM, Luna LH. Three decades after the publication of the Lamendin method for adult age-at-death estimation: Methodological evolution of the procedure and interpretations. Forensic Sci Int 2024; 355:111917. [PMID: 38215538 DOI: 10.1016/j.forsciint.2023.111917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/09/2023] [Accepted: 12/20/2023] [Indexed: 01/14/2024]
Abstract
More than three decades have passed since the publication of Lamendin et al.'s proposal in 1992. Over this time, numerous investigations have been conducted to assess the applicability of the technique in different populations with acceptable results in terms of estimation errors. The proposal by Lamendin and colleagues remains relevant today, and has made a significant contribution to adult age-at-death estimation due to its simplicity, repeatability, replicability, and high performance. Indeed, significant progress towards systematizing and strengthening the procedure has been reported in the published literature. One noteworthy advancement is the development of an international database that supports the use of Bayesian statistics for age-at-death estimation. This resource plays a crucial role in standardizing the methodology and improving the reliability for obtaining more reliable results on a global scale. The aim of this study is to investigate the historical evolution of the technique, to assess the accuracy of the results obtained by different analytic procedures, and to explore its impact in forensic applications through a systematic analysis of the specialized literature on this field. The current state of research indicates that this type of methodological research is an ongoing process, far from being completed. Many questions and challenges that require further attention to address effectively these issues remain unanswered, such as the development of non-linear regressions and probabilistic approaches, the deepening of procedures that improve global approximations, and the intensification of research focused on achieving more accurate estimations among individuals over 70 years-old. However, studies generally agree that the Lamendin technique works well for individuals between the ages of 30-60 years. It is still in force today, although the method has been significantly perfected. Despite the degree of research development in this area, further efforts are needed to improve the understanding and performance of these kinds of procedures. This will ultimately lead to an improvement in the accuracy and reliability of forensic investigation results worldwide.
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Affiliation(s)
- G Garizoain
- Forensic Science Research Laboratory (LICiF), Faculty of Medical Sciences, National University of La Plata, Argentina; CONICET, Faculty of Medical Sciences, National University of La Plata, Argentina
| | - R C Parra
- Office of the High Commissioner for Human Rights (UN Human Rights), The United Nations Organization Stabilization Mission, Democratic Republic of the Congo
| | - C M Aranda
- University of Buenos Aires, Faculty of Odontology, Endodontics Chair and Public Health Research Institute (IISAP), Bioarchaeology and Forensic Anthropology Research Unit (UIBAF), Buenos Aires, Argentina
| | - L H Luna
- University of Buenos Aires, Faculty of Philosophy and Letters and Faculty of Odontology, Endodontics Chair and Public Health Research Institute (IISAP), Bioarchaeology and Forensic Anthropology Research Unit (UIBAF), Marcelo T de Alvear 2142 9th floor (C1122), Buenos Aires, Argentina; CONICET, Multidisciplinary Institute of History and Human Sciences (IMHICIHU), Faculty of Philosophy and Letters and Faculty of Odontology, Endodontics Chair and Public Health Research Institute (IISAP), Bioarchaeology and Forensic Anthropology Research Unit (UIBAF), Marcelo T de Alvear 2142 9th floor (C1122), Buenos Aires, Argentina.
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Ceddia M, Lamberti L, Trentadue B. FEA Comparison of the Mechanical Behavior of Three Dental Crown Materials: Enamel, Ceramic, and Zirconia. MATERIALS (BASEL, SWITZERLAND) 2024; 17:673. [PMID: 38591528 PMCID: PMC10856216 DOI: 10.3390/ma17030673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/24/2024] [Accepted: 01/27/2024] [Indexed: 04/10/2024]
Abstract
The restoration of endodontically treated teeth is one of the main challenges of restorative dentistry. The structure of the tooth is a complex assembly in which the materials that make it up, enamel and dentin, have very different mechanical behaviors. Therefore, finding alternative replacement materials for dental crowns in the area of restorative care isa highly significant challenge, since materials such as ceramic and zirconia have very different stress load resistance values. The aim of this study is to assess which material, either ceramic or zirconia, optimizes the behavior of a restored tooth under various typical clinical conditions and the masticatory load. A finite element analysis (FEA) framework is developed for this purpose. The 3D model of the restored tooth is input into the FEA software (Ansys Workbench R23)and meshed into tetrahedral elements. The presence of masticatory forces is considered: in particular, vertical, 45° inclined, and horizontal resultant forces of 280 N are applied on five contact points of the occlusal surface. The numerical results show that the maximum stress developed in the restored tooth including a ceramic crown and subject to axial load is about 39.381 MPa, which is rather close to the 62.32 MPa stress computed for the natural tooth; stresses of about 18 MPa are localized at the roots of both crown materials. In the case of the zirconia crown, the stresses are much higher than those in the ceramic crown, except for the 45° load direction, while, for the horizontal loads, the stress peak in the zirconia crown is almost three times as large as its counterpart in the ceramic crown (i.e., 163.24 MPa vs. 56.114 MPa, respectively). Therefore, the zirconia crown exhibits higher stresses than enamel and ceramic that could increase in the case of parafunctions, such as bruxism. The clinician's choice between the two materials should be evaluated based on the patient's medical condition.
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Affiliation(s)
| | - Luciano Lamberti
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, 70125 Bari, Italy; (M.C.); (B.T.)
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Lee HHL, Ha SK, Kim Y, Hur J. Simultaneous analysis of advanced glycation end products using dansyl derivatization. Food Chem 2024; 432:137186. [PMID: 37657336 DOI: 10.1016/j.foodchem.2023.137186] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 06/29/2023] [Accepted: 08/16/2023] [Indexed: 09/03/2023]
Abstract
Herein, new pre-column derivatization based on dansylation is present to resolve analytical difficulties, such as chromatographic separation difficulty, in identifying and quantifying advanced glycation end products (AGEs) owing to their high hydrophilicity, wide variety, and structural similarity. The proposed analytical method facilitated the separation of 14 AGEs, including structural isomers. Limits of detection of 1.0-43.3 ng/mL and linear ranges of the double- or triple-digit were achieved. Intra- and inter-day precisions of 1.1-3.0% and 1.3-3.1%, respectively, were achieved for standard solutions, while those for food specimens were 1.4-11.2% and 1.7-15.7%, respectively. The matrix effect was insignificant with regard to the percent recoveries and differences between slopes for both the standard solutions and food specimens. Furthermore, the quantitation results of AGEs in foods (coffee, beer, and sausage) and glycated proteins revealed the potential applicability of the developed method in various fields of food chemistry and biochemistry.
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Affiliation(s)
- Hyun Hee L Lee
- Agency for Defense Development, Daejeon 34186, Republic of Korea.
| | - Sang Keun Ha
- Korea Food Research Institute, Wanju-gun, Jeollabuk-do 55365, Republic of Korea; Division of Food Biotechnology, University of Science and Technology, Daejeon, Republic of Korea
| | - Yoonsook Kim
- Korea Food Research Institute, Wanju-gun, Jeollabuk-do 55365, Republic of Korea
| | - Jinyoung Hur
- Korea Food Research Institute, Wanju-gun, Jeollabuk-do 55365, Republic of Korea; Division of Food Biotechnology, University of Science and Technology, Daejeon, Republic of Korea.
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Xie Y, Chen S, Sheng L, Sun Y, Liu S. A New Landscape of Human Dental Aging: Causes, Consequences, and Intervention Avenues. Aging Dis 2023:AD.2022.1224. [PMID: 37163430 PMCID: PMC10389823 DOI: 10.14336/ad.2022.1224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 12/24/2022] [Indexed: 05/12/2023] Open
Abstract
Aging is accompanied by physical dysfunction and physiologic degeneration that occurs over an individual's lifetime. Human teeth, like many other organs, inevitably undergo chronological aging and age-related changes throughout the lifespan, resulting in a substantial need for preventive, restorative as well as periodontal dental care. This is particularly the case for seniors at 65 years of age and those older but economically disadvantaged. Dental aging not only interferes with normal chewing and digestion, but also affects daily appearance and interpersonal communications. Further dental aging can incur the case of multiple disorders such as oral cancer, encephalitis, and other systemic diseases. In the next decades or even hundreds of years, the proportion of the elderly in the global population will continue to rise, a tendency that attracts increasing attention across multiple scientific and medical disciplines. Dental aging will bring a variety of problems to the elderly themselves and poses serious challenges to the medical profession and social system. A reduced, but functional dentition comprising 20 teeth in occlusion has been proposed as a measurement index of successful dental aging. Healthy dental aging is critical to healthy aging, from both medical and social perspectives. To date, biomedical research on the causes, processes and regulatory mechanisms of dental aging is still in its infancy. In this article, updated insights into typical manifestations, associated pathologies, preventive strategies and molecular changes of dental aging are provided, with future research directions largely projected.
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Affiliation(s)
- Yajia Xie
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Shanghai Stomatological Hospital, Fudan University, Shanghai, China
- Department of Endodontics, Shanghai Stomatological Hospital, Fudan University, Shanghai, China
| | - Shuang Chen
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Shanghai Stomatological Hospital, Fudan University, Shanghai, China
| | - Lu Sheng
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Shanghai Stomatological Hospital, Fudan University, Shanghai, China
| | - Yu Sun
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
- Department of Pharmacology, Institute of Aging Medicine, Binzhou Medical University, Yantai, Shandong, China
- Department of Medicine and VAPSHCS, University of Washington, Seattle, WA 98195, USA
| | - Shangfeng Liu
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Shanghai Stomatological Hospital, Fudan University, Shanghai, China
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11
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Cho DH, Aguayo S, Cartagena-Rivera AX. Atomic force microscopy-mediated mechanobiological profiling of complex human tissues. Biomaterials 2023; 303:122389. [PMID: 37988897 PMCID: PMC10842832 DOI: 10.1016/j.biomaterials.2023.122389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/30/2023] [Accepted: 11/04/2023] [Indexed: 11/23/2023]
Abstract
Tissue mechanobiology is an emerging field with the overarching goal of understanding the interplay between biophysical and biochemical responses affecting development, physiology, and disease. Changes in mechanical properties including stiffness and viscosity have been shown to describe how cells and tissues respond to mechanical cues and modify critical biological functions. To quantitatively characterize the mechanical properties of tissues at physiologically relevant conditions, atomic force microscopy (AFM) has emerged as a highly versatile biomechanical technology. In this review, we describe the fundamental principles of AFM, typical AFM modalities used for tissue mechanics, and commonly used elastic and viscoelastic contact mechanics models to characterize complex human tissues. Furthermore, we discuss the application of AFM-based mechanobiology to characterize the mechanical responses within complex human tissues to track their developmental, physiological/functional, and diseased states, including oral, hearing, and cancer-related tissues. Finally, we discuss the current outlook and challenges to further advance the field of tissue mechanobiology. Altogether, AFM-based tissue mechanobiology provides a mechanistic understanding of biological processes governing the unique functions of tissues.
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Affiliation(s)
- David H Cho
- Section on Mechanobiology, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Sebastian Aguayo
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; Schools of Engineering, Medicine, and Biological Sciences, Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexander X Cartagena-Rivera
- Section on Mechanobiology, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA.
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12
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Marques JV, Carlos NR, Turssi CP, França FMG, Vieira Junior WF, Basting RT. Effectiveness of changing the color of darker teeth is potentiated by association with violet LED light. Photodiagnosis Photodyn Ther 2023; 44:103794. [PMID: 37699468 DOI: 10.1016/j.pdpdt.2023.103794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/17/2023] [Accepted: 09/07/2023] [Indexed: 09/14/2023]
Abstract
BACKGROUND The effectiveness of in-office bleaching protocols performed with violet LED light either combined with a bleaching agent containing 37% carbamide peroxide, or not, was determined by comparing teeth with different degrees of darkening. METHODOLOGY Eighty bovine incisors were separated into groups of "light" teeth (luminosity greater than or equal to B3) and "dark" teeth (less than or equal to A3.5) to receive the protocols: HP - 35% hydrogen peroxide (Whiteness HP), CP - 37% carbamide peroxide (Whiteness SuperEndo), LED - violet LED light (Bright Max Whitening), CPLED - CP associated with the LED. For color analysis the CIEL*a*b* e WID, ΔEab, ΔE00 e ΔWID parameters were used. Data were analyzed using Mann-Whitney, Kruskal-Wallis, Dunn, Friedman or Nemenyi tests (α = 5%). RESULTS HP and CP resulted in similar color change values (ΔEab, ΔE00 e ΔWID) for light and dark teeth (p > 0.05). Dark teeth showed better bleaching effectiveness (ΔEab, ΔE00 e ΔWID) than light teeth when CPLED was used (p < 0.05). LED showed color change that were below the limits of acceptability and perceptibility for ΔWID. CONCLUSION light teeth are effectively bleached with the use of HP or CP, whereas dark teeth respond better to treatment with the CPLED protocol. Violet LED used alone did not show a satisfactory result.
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Affiliation(s)
- Joana Vasconcellos Marques
- Faculdade São Leopoldo Mandic, Rua José Rocha Junqueira 13, Bairro Swift, Campinas, CEP: 13045-755, São Paulo, Brazil
| | - Natália Russo Carlos
- Faculdade São Leopoldo Mandic, Rua José Rocha Junqueira 13, Bairro Swift, Campinas, CEP: 13045-755, São Paulo, Brazil
| | - Cecilia Pedroso Turssi
- Faculdade São Leopoldo Mandic, Rua José Rocha Junqueira 13, Bairro Swift, Campinas, CEP: 13045-755, São Paulo, Brazil
| | | | | | - Roberta Tarkany Basting
- Faculdade São Leopoldo Mandic, Rua José Rocha Junqueira 13, Bairro Swift, Campinas, CEP: 13045-755, São Paulo, Brazil.
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13
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Iosif L, Dimitriu B, Niţoi DF, Amza O. Endodontic Dentistry: Analysis of Dentinal Stress and Strain Development during Shaping of Curved Root Canals. Healthcare (Basel) 2023; 11:2918. [PMID: 37998410 PMCID: PMC10671542 DOI: 10.3390/healthcare11222918] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/25/2023] [Accepted: 10/29/2023] [Indexed: 11/25/2023] Open
Abstract
BACKGROUND Endodontic shaping causes stress and strain in the root canal dentin. Dentin microcracks have the potential to be later followed by root fractures occurring under the occlusal load. The aim of our research was to theoretically determine the values of such dentinal states of stress and strain during the endodontic shaping of curved root canals using finite element analysis (FEA). METHODS To highlight the stress concentrations in dentin, two geometric models were created considering the volume of the curved dental root and the contact between the endodontic file and the root canal walls. The application of forces with different values was simulated both on a uniform curved root canal and on a root canal with an apical third curvature of 25° as they would be applied during the preparation of a root canal. RESULTS In the case of the first model, which was acted upon with a force of 5 N, the deformations of the root canal appeared along the entire working length, reaching the highest values in the apical third of the root, although there were no geometric changes in the shape of the root canal. Regarding the second root model, with an apical third curvature of 25°, although the applied force was 2 N, the deformations were accompanied by geometric changes in the shape of the root, especially in the upper part of the apical third. At a higher force of 7 N exerted on the endodontic file, the geometric shape changed, and the deformation reached extreme critical values. The resulting tensile stresses appearing in the experimental structure varied similarly to the deformations. CONCLUSIONS Significant stress and strain can develop, especially in the apical third of curved root canals during their shaping, and the risk of cracks is higher for endodontically treated teeth presenting severe curvatures in the apical third of the root.
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Affiliation(s)
- Laura Iosif
- Faculty of Dentistry, University of Medicine and Pharmacy “Carol Davila” Bucharest, 17–21 Calea Plevnei Street, Sector 1, 010221 Bucharest, Romania; (L.I.); (O.A.)
| | - Bogdan Dimitriu
- Faculty of Dentistry, University of Medicine and Pharmacy “Carol Davila” Bucharest, 17–21 Calea Plevnei Street, Sector 1, 010221 Bucharest, Romania; (L.I.); (O.A.)
| | - Dan Florin Niţoi
- Faculty of Industrial Engineering and Robotics, University POLITEHNICA of Bucharest, 313 Splaiul Independenței Street, 060042 Bucharest, Romania
| | - Oana Amza
- Faculty of Dentistry, University of Medicine and Pharmacy “Carol Davila” Bucharest, 17–21 Calea Plevnei Street, Sector 1, 010221 Bucharest, Romania; (L.I.); (O.A.)
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14
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Mihara Y, Ishimoto T, Ozasa R, Omura T, Yamato Y, Yamada T, Okamoto A, Matsuyama Y, Nakano T. Deterioration of apatite orientation in the cholecystokinin B receptor gene (Cckbr)-deficient mouse femurs. J Bone Miner Metab 2023; 41:752-759. [PMID: 37676507 DOI: 10.1007/s00774-023-01460-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 07/20/2023] [Indexed: 09/08/2023]
Abstract
INTRODUCTION The discrepancy between bone mineral density (BMD), the gold standard for bone assessment, and bone strength is a constraint in diagnosing bone function and determining treatment strategies for several bone diseases. Gastric hypochlorhydria induced by clinically used proton pump inhibitor (PPI) therapy indicates a discordance between changes in BMD and bone strength. Here, we used Cckbr-deficient mice with gastric hypochlorhydria to examine the effect of gastric hypochlorhydria on bone mass, BMD, and preferential orientation of the apatite crystallites, which is a strong indicator of bone strength. MATERIALS AND METHODS Cckbr-deficient mice were created, and their femurs were analyzed for BMD and preferential orientation of the apatite c-axis along the femoral long axis. RESULTS Cckbr-deficient mouse femurs displayed a slight osteoporotic bone loss at 18 weeks of age; however, BMD was comparable to that of wild-type mice. In contrast, apatite orientation in the femur mid-shaft significantly decreased from 9 to 18 weeks. To the best of our knowledge, this is the first report demonstrating the deterioration of apatite orientation in the bones of Cckbr-deficient mice. CONCLUSION Lesions in Cckbr-deficient mice occurred earlier in apatite orientation than in bone mass. Hence, bone apatite orientation may be a promising method for detecting hypochlorhydria-induced osteoporosis caused by PPI treatment and warrants urgent clinical applications.
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Affiliation(s)
- Yuki Mihara
- Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-Ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Ryosuke Ozasa
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Takao Omura
- Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-Ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Yu Yamato
- Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-Ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Tomohiro Yamada
- Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-Ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Ayako Okamoto
- Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-Ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Yukihiro Matsuyama
- Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-Ku, Hamamatsu, Shizuoka, 431-3192, Japan.
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka, 565-0871, Japan.
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Chen S, Arola D, Ricucci D, Bergeron BE, Branton JA, Gu LS, Tay FR. Biomechanical perspectives on dentine cracks and fractures: Implications in their clinical management. J Dent 2023; 130:104424. [PMID: 36657703 DOI: 10.1016/j.jdent.2023.104424] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/09/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVES The present review discussed the biomechanical properties of cracks and fractures in crown and root dentine and attempted to explain why cracked teeth and vertical root fractures are so frequent despite the existence of multiple crack toughening mechanisms in dentine. The implications of this knowledge were used to justify how these defects are managed clinically. DATA, SOURCES AND STUDY SELECTION Literature search was conducted on PubMed, Web of Science, and Scopus for a narrative review on fracture mechanics of crown and root dentine as well as the clinical management of cracked teeth and teeth with vertical root fracture. CONCLUSIONS Although dentine is tougher and less brittle than enamel, it's facture toughness is considerably lower than most ductile metals. Because the initiation toughness of dentine is very low, cracks initiate from incipient damage under low stress While crack toughening mechanisms exist that enable dentine to resist crack extension, these mechanisms are often inadequate for protecting dentine from crack propagation that ultimately leads to catastrophic failure. Additional factors such as ageing also reduces the resistance of dentine to crack growth. Because dentine cracks are eventually filled with bacteria biofilms upon exposure to oral fluids, they enable rapid bacteria ingress into the dental pulp via open dentinal tubules. To date, treatment options for cracked teeth are limited. While most teeth with vertical root fracture are recommended for extraction, new strategies have been reported that appeared to achieve short-term success in preserving these teeth. CLINICAL SIGNIFICANCE Current strategies for the management for dentine cracks and fractures are limited and their long-term effectiveness remain uncertain. Understanding the characteristics, toughening mechanism and weakening factors of tooth cracks is helpful in designing better treatment.
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Affiliation(s)
- Sishi Chen
- Hospital of Stomatology, Sun Yat-sen University & Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, PR China
| | - Dwayne Arola
- Department of Materials Science and Engineering, University of Washington, Seattle, WA USA
| | | | - Brian E Bergeron
- Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - John A Branton
- Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Li-Sha Gu
- Hospital of Stomatology, Sun Yat-sen University & Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, PR China.
| | - Franklin R Tay
- Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA.
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Dexamethasone and zinc loaded polymeric nanoparticles reinforce and remineralize coronal dentin. A morpho-histological and dynamic-biomechanical study. Dent Mater 2023; 39:41-56. [PMID: 36460577 DOI: 10.1016/j.dental.2022.11.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 11/18/2022] [Accepted: 11/25/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To investigate the effect of novel polymeric nanoparticles (NPs) doped with dexamethasone (Dex) on viscoelasticity, crystallinity and ultra-nanostructure of the formed hydroxyapatite after NPs dentin infiltration. METHODS Undoped-NPs, Dex-doped NPs (Dex-NPs) and zinc-doped-Dex-NPs (Zn-Dex-NPs) were tested at dentin, after 24 h and 21 d. A control group without NPs was included. Coronal dentin surfaces were studied by nano-dynamic mechanical analysis measurements, atomic force microscopy, X-ray diffraction and transmission electron microscopy. Mean and standard deviation were analyzed by ANOVA and Student-Newman-Keuls multiple comparisons (p < 0.05). RESULTS At 21 d of storage time, both groups doped with Dex exhibited the highest complex, storage and loss moduli among groups. Zn-Dex-NPs and Dex-NPs promoted the highest and lowest tan delta values, respectively. Dex-NPs contributed to increase the fibril diameters of dentin collagen over time. Dentin surfaces treated with Zn-Dex-NPs attained the lowest nano-roughness values, provoked the highest crystallinity, and produced the longest and shortest crystallite and grain size. These new crystals organized with randomly oriented lattices. Dex-NPs induced the highest microstrain. Crystalline and amorphous matter was present in the mineral precipitates of all groups, but Zn and Dex loaded NPs helped to increase crystallinity. SIGNIFICANCE Dentin treated with Zn-Dex-NPs improved crystallographic and atomic order, providing structural stability, high mechanical performance and tissue maturation. Amorphous content was also present, so high hydroxyapatite solubility, bioactivity and remineralizing activity due to the high ion-rich environment took place in the infiltrated dentin.
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Chen Y, Maghami E, Bai X, Huang C, Pow EHN, Tsoi JKH. Which dentine analogue material can replace human dentine for crown fatigue test? Dent Mater 2023; 39:86-100. [PMID: 36503862 DOI: 10.1016/j.dental.2022.11.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/19/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To seek dentine analogue materials in combined experimental, analytical, and numerical approaches on the mechanical properties and fatigue behaviours that could replace human dentine in a crown fatigue laboratory test. METHODS A woven glass fibre-filled epoxy (NEMA grade G10; G10) and a glass fibre-reinforced polyamide-nylon (30% glass fibre reinforced polyamide-nylon 6,6; RPN) were investigated and compared with human dentine (HD). Flexural strength and elastic modulus (n = 10) were tested on beam-shaped specimens via three-point bending, while indentation hardness (n = 3) was tested after fracture. Abutment substrates of G10, RPN and HD were prepared and resin-bonded with monolithic lithium disilicate crowns (n = 10), then subjected to wet cyclic loading in a step-stress manner (500 N initial load, 100 N step size, 100,000 cycles per step, 20 Hz frequency). Data were statistically analysed using Kruskal-Wallis one-way ANOVA followed by post-hoc comparisons (α = 0.05). Survival probability estimation was performed by Mantel-Cox Log-Rank test with 95% confidence intervals. The fatigue failure load (FFL) and the number of cycles until failure (NCF) were evaluated with Weibull statistics. Finite Element Models of the fatigue test were established for stress distribution analysis and lifetime prediction. Fractographic observations were qualitatively analysed. RESULTS The flexural strength of HD (164.27 ± 14.24 MPa), G10 (116.48 ± 5.93 MPa), and RPN (86.73 ± 3.56 MPa) were significantly different (p < 0.001), while no significant difference was observed in their flexural moduli (p = 0.377) and the indentation hardness between HD and RPN (p = 0.749). The wet cyclic fatigue test revealed comparable mean FFL and NCF of G10 and RPN to HD (p = 0.237 and 0.294, respectively) and similar survival probabilities for the three groups (p = 0.055). However, RPN promotes higher stability and lower deviation of fatigue test results than G10 in Weibull analysis and FEA. SIGNIFICANCE Even though dentine analogue materials might exhibit similar elastic properties and fatigue performance to human dentine, different reliabilities of fatigue on crown-dentine analogues were shown. RPN seems to be a better substrate that could provide higher reliability and predictability of laboratory study results.
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Affiliation(s)
- Yanning Chen
- Dental Materials Science, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - Ebrahim Maghami
- Department of Mechanical Engineering and Mechanics, College of Engineering, Drexel University, Philadelphia, PA 19104, USA
| | - Xuedong Bai
- Dental Materials Science, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - Cui Huang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory for Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Edmond Ho Nang Pow
- Prosthodontics, Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - James Kit Hon Tsoi
- Dental Materials Science, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
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Weerakoon AT, Meyers IA, Thomson DH, Cooper C, Ford PJ, Symons AL. Coronal dentin differs between young and mature adult humans: A systematic review. Arch Oral Biol 2022; 144:105553. [DOI: 10.1016/j.archoralbio.2022.105553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/02/2022]
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Weerakoon AT, Condon N, Cox TR, Sexton C, Cooper C, Meyers IA, Thomson D, Ford PJ, Roy S, Symons AL. Dynamic dentin: A quantitative microscopic assessment of age and spatial changes to matrix architecture, peritubular dentin, and collagens types I and III. J Struct Biol 2022; 214:107899. [PMID: 36208858 DOI: 10.1016/j.jsb.2022.107899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/16/2022] [Accepted: 09/19/2022] [Indexed: 12/07/2022]
Abstract
To investigate age and site-related changes to human dentin collagen, sound human teeth collected from donors aged 13-29 (young) and 50-74 (aged) years (n = 9/group) were cut to shallow and deep sites. Dentin collagen orientation and fibril bundling was investigated using the Picrosirius Red (PSR) stain observed under cross-polarized light microscopy (Pol), and collagen distribution was investigated using Confocal Laser Scanning Microscopy (CLSM). Collagen types III to I distribution in peritubular dentin (PTD) was revealed using Herovici stain and brightfield microscopy. Image analysis software and linear mixed modelling quantified outcomes. In situ dentin collagen was observed using Xenon Plasma Focussed Ion Beam Scanning Electron Microscopy (Xe PFIB-SEM). The PSR-Pol analysis revealed less coherently aligned and more bundled collagen fibrils in aged dentin (P = 0.005). Deep inner dentin collagen in both groups were less coherently aligned with reduced bundling. Regardless of age, CLSM showed collagen distribution remained stable; and more collagen type III was detectable in PTD located in inner dentin (Young: P = 0.006; Aged: P = 0.008). Observations following Xe PFIB-SEM cross-sectioning showed apatite-like deposits surrounding large intratubular collagen fibers, and evidence of smaller intertubular dentin collagen fibrils in situ. In conclusion, aging changes collagen network architecture, but not distribution or content.
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Affiliation(s)
- Arosha T Weerakoon
- School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia.
| | - Nicholas Condon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Thomas R Cox
- Garvan Institute of Medical Research & School of Clinical Medicine, UNSW, Sydney, Australia
| | - Christopher Sexton
- School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia
| | - Crystal Cooper
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Queensland, Australia; Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, Western Australia, Australia
| | - Ian A Meyers
- School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia
| | - David Thomson
- School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia
| | - Pauline J Ford
- School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia
| | - Sandrine Roy
- Translational Research Institute, Brisbane, Queensland, Australia; Olympus Life Science, Australia
| | - Anne L Symons
- School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia
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Maghami E, Najafi AR. Influence of age-related changes on crack growth trajectories and toughening mechanisms in human dentin. Dent Mater 2022; 38:1789-1800. [DOI: 10.1016/j.dental.2022.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 11/30/2022]
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On the Mechanical Properties of Hybrid Dental Materials for CAD/CAM Restorations. Polymers (Basel) 2022; 14:polym14163252. [PMID: 36015509 PMCID: PMC9413303 DOI: 10.3390/polym14163252] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 11/30/2022] Open
Abstract
Two hybrid dental materials available for computer-aided design and manufacturing (CAD/CAM) dental restorations have been selected to explore their potential. On the one hand, the scarcely investigated polymer-based material Vita Enamic® (VE) and, on the other hand, the leucite-based material IPS Empress® CAD (EC). Their micro-structure and mechanical performance were analyzed in two environments: directly as received by the manufacturer (AR), and after immersion and storage in artificial saliva (AS) for 30 days to determine the influence of the saliva effect. To avoid an inappropriate selection of materials for clinical use, a full understanding of their mechanical behavior is essential. Therefore, this investigation aims to determine the micro-structural and chemical composition by field emission scanning electron microscopy (FE-SEM) and X-ray fluorescence analysis, establishing the density, micro- and nano-hardness, the nano-elastic modulus, and the flexural strength and fracture toughness (by introducing a femto-laser notch to replicate a real crack). In addition, fracture surfaces of the broken samples were analyzed to correlate the failure micro-mechanisms with their mechanical properties. Results indicate that while the crystalline phase of the materials is very similar (composed of SiO2 and Al2O3), the micro-structure and mechanical behavior is not. The material EC, with finer micro-structure, exhibits a higher mechanical performance but with greater variability of results. Furthermore, the material VE, with a 25 vol.% polymer phase, shows a mechanical performance similar to enamel and dentin and therefore more similar to human behavior.
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Watanabe R, Matsugaki A, Ishimoto T, Ozasa R, Matsumoto T, Nakano T. A Novel Ex Vivo Bone Culture Model for Regulation of Collagen/Apatite Preferential Orientation by Mechanical Loading. Int J Mol Sci 2022; 23:ijms23137423. [PMID: 35806427 PMCID: PMC9267238 DOI: 10.3390/ijms23137423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022] Open
Abstract
The anisotropic microstructure of bone, composed of collagen fibers and biological apatite crystallites, is an important determinant of its mechanical properties. Recent studies have revealed that the preferential orientation of collagen/apatite composites is closely related to the direction and magnitude of in vivo principal stress. However, the mechanism of alteration in the collagen/apatite microstructure to adapt to the mechanical environment remains unclear. In this study, we established a novel ex vivo bone culture system using embryonic mouse femurs, which enabled artificial control of the mechanical environment. The mineralized femur length significantly increased following cultivation; uniaxial mechanical loading promoted chondrocyte hypertrophy in the growth plates of embryonic mouse femurs. Compressive mechanical loading using the ex vivo bone culture system induced a higher anisotropic microstructure than that observed in the unloaded femur. Osteocytes in the anisotropic bone microstructure were elongated and aligned along the long axis of the femur, which corresponded to the principal loading direction. The ex vivo uniaxial mechanical loading successfully induced the formation of an oriented collagen/apatite microstructure via osteocyte mechano-sensation in a manner quite similar to the in vivo environment.
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Affiliation(s)
- Ryota Watanabe
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan; (R.W.); (A.M.); (T.I.); (R.O.)
- Teijin Nakashima Medical Co., Ltd., 688-1 Joto-Kitagata, Higashi-ku, Okayama 709-0625, Japan
| | - Aira Matsugaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan; (R.W.); (A.M.); (T.I.); (R.O.)
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan; (R.W.); (A.M.); (T.I.); (R.O.)
| | - Ryosuke Ozasa
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan; (R.W.); (A.M.); (T.I.); (R.O.)
| | - Takuya Matsumoto
- Department of Biomaterials, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan;
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan; (R.W.); (A.M.); (T.I.); (R.O.)
- Correspondence: ; Tel.: +81-6-6879-7505
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23
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Leiva-Sabadini C, Schuh CM, Barrera NP, Aguayo S. Ultrastructural characterisation of young and aged dental enamel by atomic force microscopy. J Microsc 2022; 288:185-192. [PMID: 35621144 DOI: 10.1111/jmi.13126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/28/2022] [Accepted: 05/19/2022] [Indexed: 11/28/2022]
Abstract
Recent advances in atomic force microscopy (AFM) have allowed the characterisation of dental-associated biomaterials and biological surfaces with high-resolution. In this context, the topography of dental enamel - the hardest mineralised tissue in the body - has been explored with AFM-based approaches at the micro-scale. With age, teeth are known to suffer changes that can impact their structural stability and function; however, changes in enamel structure because of ageing have not yet been explored with nanoscale resolution. Therefore, the aim of this exploratory work was to optimise an approach to characterise the ultrastructure of dental enamel and determine potential differences in topography, hydroxyapatite (HA) crystal size, and surface roughness at the nanoscale associated to ageing. For this, a total of six teeth were collected from human donors from which enamel specimens were prepared. By employing intermittent contact (AC mode) imaging, HA crystals were characterised in both transversal and longitudinal orientation (respect to surface plane) with high-resolution in environmental conditions. The external enamel surface displayed the presence of a pellicle-like coating on its surface, that was not observable on cleaned specimens. Acid-etching exposed crystals that were imaged and morphologically characterised in high-resolution at the nanoscale in both the external and internal regions of enamel in older and younger specimens. Our results demonstrated important individual variations in HA crystal width and roughness parameters across the analysed specimens; however, an increase in surface roughness and decrease in HA width was observed for the pooled older external enamel group compared to younger specimens. Overall, high-resolution AFM was an effective approach for the qualitative and quantitative characterisation of human dental enamel ultrastructure. Future work should focus on exploring the ageing of dental enamel with increased sample sizes to compensate for individual differences as well as other potential confounding factors such as behavioural habits and mechanical forces. Lay abstract: Currently, advanced microscopy techniques such as atomic force microscopy (AFM) can be used to characterise surfaces relevant to dentistry with great detail. Among these surfaces of interest, dental enamel - the hardest mineralised tissue in the body- is important as it protects the deeper areas of the tooth from harmful stimuli such as sudden temperature changes, bacterial penetration, and chemical attack. Also, dental enamel is an important surface for the adhesion of some types of dental restorations; thus, its structure and organisation is highly relevant for both dental scientists and clinicians. With age, teeth are known to suffer changes that can impact their structural stability and function; however, changes in enamel structure as a result of ageing have not yet been explored with nanoscale resolution. It is necessary to develop and optimise AFM-based techniques in order to process specimens from dental samples across different age groups for ageing-associated nanoscale studies in the future. Therefore, the aim of this investigation was to optimise an approach to characterise the ultrastructure of dental enamel and determine potential differences in enamel topography, hydroxyapatite (HA) crystal size, and surface roughness at the nanoscale associated to ageing. For this, human enamel specimens obtained from a total of six teeth were collected and analysed with AFM, and HA crystals were characterised in both transversal and longitudinal orientation with high-resolution in environmental conditions. Upon AFM observation, sound superficial enamel displayed the presence of a pellicle-like coating on its surface, that was not observable after specimens were cleaned. Furthermore, acid-etching exposed HA crystals that were imaged and morphologically characterised in high-resolution at the nanoscale across different regions of enamel in older and younger specimens. We observed important individual variations in HA crystal width and roughness parameters across the analysed specimens and groups, suggesting individual as well as age-associated differences. Overall, high-resolution AFM was an effective approach for the qualitative and quantitative characterisation of human dental enamel ultrastructure at the nanometer range with minimal sample preparation. This proof-of-concept work can pave the way for future studies employing increased sample sizes to compensate for individual differences and population level factors. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Camila Leiva-Sabadini
- School of Dentistry, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Christina Map Schuh
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - Nelson P Barrera
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sebastian Aguayo
- School of Dentistry, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.,Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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24
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Ozasa R, Saito M, Ishimoto T, Matsugaki A, Matsumoto Y, Nakano T. Combination treatment with ibandronate and eldecalcitol prevents osteoporotic bone loss and deterioration of bone quality characterized by nano-arrangement of the collagen/apatite in an ovariectomized aged rat model. Bone 2022; 157:116309. [PMID: 34998980 DOI: 10.1016/j.bone.2021.116309] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 12/13/2022]
Abstract
Combination therapy with bisphosphonates and vitamin D3 analogs has been frequently used for the treatment of osteoporosis. However, its effects on bone anisotropies, such as orientations of collagen and apatite at the nanometer-scale, which is a promising bone quality index, and its trabecular architecture at the micrometer scale, are not well understood despite its important mechanical properties and its role in fracture risk. In the present study, we analyzed the effects of ibandronate (IBN), eldecalcitol (ELD), and their combination on the collagen/apatite orientation and trabecular architectural anisotropy using an estrogen-deficiency-induced osteoporotic rat model. Estrogen deficiency caused by ovariectomy (OVX) excessively increased the degree of collagen/apatite orientation or trabecular architectural anisotropy along the craniocaudal axis in the lumbar vertebra compared to that of the sham-operated group. The craniocaudal axis corresponds to the direction of principal stress in the spine. The excessive material anisotropy in the craniocaudal axis contributed to the enhanced Young's modulus, which may compensate for the reduced mechanical resistance by bone loss to some extent. The solo administration of IBN and ELD prevented the reduction of bone fraction (BV/TV) determined by μ-CT, and combination therapy showed the highest efficacy in BV/TV gain. Furthermore, the solo administration and combination treatment significantly decreased the degree of collagen/apatite orientation to the sham level. Based on the results of bone mass and collagen/apatite orientation, combination treatment is an effective strategy. This is the first report to demonstrate the efficacy of IBN, ELD, and combination treatment with IBN and ELD relative to the bone micro-architectural anisotropy characterized by collagen/apatite orientation.
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Affiliation(s)
- Ryosuke Ozasa
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Mitsuru Saito
- Department of Orthopaedic Surgery, Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan.
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Aira Matsugaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Yoshihiro Matsumoto
- Product Research Department, Kamakura Research Laboratories, Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan.
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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25
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Schuh CMAP, Leiva-Sabadini C, Huang S, Barrera NP, Bozec L, Aguayo S. Nanomechanical and Molecular Characterization of Aging in Dentinal Collagen. J Dent Res 2022; 101:840-847. [PMID: 35130787 DOI: 10.1177/00220345211072484] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Methylglyoxal (MGO) is an important molecule derived from glucose metabolism with the capacity of attaching to collagen and generating advanced glycation end products (AGEs), which accumulate in tissues over time and are associated with aging and diseases. However, the accumulation of MGO-derived AGEs in dentin and their effect on the nanomechanical properties of dentinal collagen remain unknown. Thus, the aim of the present study was to quantify MGO-based AGEs in the organic matrix of human dentin as a function of age and associate these changes with alterations in the nanomechanical and ultrastructural properties of dentinal collagen. For this, 12 healthy teeth from <26-y-old and >50-y-old patients were collected and prepared to obtain crown and root dentin discs. Following demineralization, MGO-derived AGEs were quantified with a competitive ELISA. In addition, atomic force microscopy nanoindentation was utilized to measure changes in elastic modulus in peritubular and intertubular collagen fibrils. Finally, principal component analysis was carried out to determine aging profiles for crown and root dentin. Results showed an increased presence of MGO AGEs in the organic matrix of dentin in the >50-y-old specimens as compared with the <26-y-old specimens in crown and root. Furthermore, an increase in peritubular and intertubular collagen elasticity was observed in the >50-y-old group associated with ultrastructural changes in the organic matrix as determined by atomic force microscopy analysis. Furthermore, principal component analysis loading plots suggested different "aging profiles" in crown and root dentin, which could have important therapeutic implications in restorative and adhesive dentistry approaches. Overall, these results demonstrate that the organic matrix of human dentin undergoes aging-related changes due to MGO-derived AGEs with important changes in the nanomechanical behavior of collagen that may affect diagnostic and restorative procedures in older people.
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Affiliation(s)
- C M A P Schuh
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - C Leiva-Sabadini
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - S Huang
- Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - N P Barrera
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - L Bozec
- Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - S Aguayo
- Dentistry School, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.,Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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26
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Ozasa R, Matsugaki A, Ishimoto T, Kamura S, Yoshida H, Magi M, Matsumoto Y, Sakuraba K, Fujimura K, Miyahara H, Nakano T. Bone fragility via degradation of bone quality featured by collagen/apatite micro-arrangement in human rheumatic arthritis. Bone 2022; 155:116261. [PMID: 34826630 DOI: 10.1016/j.bone.2021.116261] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 12/20/2022]
Abstract
Although increased bone fragility is a well-recognized consequence in patients with rheumatoid arthritis (RA), the essential cause of degenerate bone strength remains unknown. This study aimed to determine factors contributing to bone dysfunction in RA by focusing on the bone matrix micro-arrangement, based on the preferential orientation of collagen and the related apatite c-axis as a bone quality index. The classical understanding of RA is limited to its severe pathological conditions associated with inflammation-induced bone loss. This study examined periarticular proximal tibiae from RA patients as compared with osteoarthritis (OA) patients as controls. Bone tissue material strength was disrupted in the RA group compared with the control. Collagen/apatite micro-arrangement and vBMD were significantly lower in the RA group, and the rate of decrease in apatite c-axis orientation (-45%) was larger than that in vBMD (-22%). Multiple regression analysis showed that the degree of apatite c-axis orientation (β = 0.52, p = 1.9 × 10-2) significantly contributed to RA-induced bone material impairment as well as vBMD (β = 0.46, p = 3.8 × 10-2). To the best of our knowledge, this is the first report to demonstrate that RA reduces bone material strength by deteriorating the micro-arrangement of collagen/apatite bone matrix, leading to decreased fracture resistance. Our findings represent the significance of bone quality-based analysis for precise evaluation and subsequent therapy of the integrity and soundness of the bone in patients with RA.
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Affiliation(s)
- Ryosuke Ozasa
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Aira Matsugaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Satoshi Kamura
- Department of Orthopaedic Surgery, National Hospital Organization, Kyushu Medical Center, 1-8-1 Jigyouhama chuo-ku, Fukuoka, Fukuoka 811-1395, Japan
| | - Hiroto Yoshida
- Product Research Department, Kamakura Research Laboratories, Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
| | - Mayu Magi
- Product Research Department, Kamakura Research Laboratories, Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
| | - Yoshihiro Matsumoto
- Product Research Department, Kamakura Research Laboratories, Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
| | - Koji Sakuraba
- Department of Orthopaedic Surgery, National Hospital Organization, Kyushu Medical Center, 1-8-1 Jigyouhama chuo-ku, Fukuoka, Fukuoka 811-1395, Japan
| | - Kenjiro Fujimura
- Department of Orthopaedic Surgery, National Hospital Organization, Kyushu Medical Center, 1-8-1 Jigyouhama chuo-ku, Fukuoka, Fukuoka 811-1395, Japan
| | - Hisaaki Miyahara
- Department of Orthopaedic Surgery, National Hospital Organization, Kyushu Medical Center, 1-8-1 Jigyouhama chuo-ku, Fukuoka, Fukuoka 811-1395, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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27
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Heberer MT, Roggendorf HC, Faber FJ, Lawrenz NA, Frankenberger R, Roggendorf MJ. Longitudinal craze line propagation in human root dentin after instrumentation with NiTi rotary files of different instrument tapers after long-term chewing simulation. Clin Oral Investig 2021; 26:2671-2679. [PMID: 34787719 PMCID: PMC8898247 DOI: 10.1007/s00784-021-04238-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/15/2021] [Indexed: 11/26/2022]
Abstract
Objectives The aim of this study was to investigate whether file design and taper significantly influence microcrack initiation during machine preparation. Materials and methods Sixty extracted teeth with straight single canals were selected. The teeth were randomly assigned to four groups based on their root canal anatomy and the corresponding NiTi rotary file system (I, Mtwo; II, ProTaper Universal; III, F6 SkyTaper; control, no preparation and filling). The root canals of the experimental groups were filled using the single-cone technique. The tested teeth were all subjected to a mechanical chewing simulation with flat lead loading over a period of 3 years (corresponding to 150,000 cycles). The teeth were checked for dentinal defects (accumulative crack growth in length) under the digital microscope (Keyence VHX-5000) at time 0 (baseline prior to chewing simulation) and after 3, 6, 12, 24, and 36 months of loading. The cumulative crack increase was statistically analyzed using the Kruskal–Wallis test, Jonckheere–Terpstra test, and the Wilcoxon rank-sum test. The significance was set at p < 0.05. Results In contrast to preparation with greater-tapered instruments, ProTaper Universal (group II) and F6 SkyTaper (group III) instrumentation with the smaller tapered Mtwo files (group I) showed less accumulative propagation of craze lines (p < 0.05) at all time points. Conclusion Instruments with greater taper for root canal instrumentation should be used with care to avoid negative long-term effects in the form of propagation of dentinal defects over time. A positive cutting-edge angle and a smaller taper have a positive effect on a lower craze line development. Clinical relevance Instruments with a positive cutting-edge angle and a smaller taper are beneficial for the long-term preservation of dentinal tooth structure.
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Affiliation(s)
- Marie-Therese Heberer
- Department of Operative Dentistry, Endodontics, and Pediatric Dentistry, Philipps University Marburg and University Hospital Giessen and Marburg, Campus Marburg, Georg-Voigt-Straße 3, 35039, Marburg, Germany.
| | - Hubert C Roggendorf
- Interdisciplinary Department of Oral Surgery an Implantology, University of Cologne, Kerpener Straße 32, 50931, Cologne, Germany
| | - Franz-Josef Faber
- Pre-Clinical Department, University of Cologne, Kerpener Straße 32, 50931, Cologne, Germany
| | - Nicolai-Alexander Lawrenz
- Department of Mathematics and Computer Science, Philipps University of Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - Roland Frankenberger
- Department of Operative Dentistry, Endodontics, and Pediatric Dentistry, Philipps University Marburg and University Hospital Giessen and Marburg, Campus Marburg, Georg-Voigt-Straße 3, 35039, Marburg, Germany
| | - Matthias J Roggendorf
- Department of Operative Dentistry, Endodontics, and Pediatric Dentistry, Philipps University Marburg and University Hospital Giessen and Marburg, Campus Marburg, Georg-Voigt-Straße 3, 35039, Marburg, Germany
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28
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Algarni AA, Lippert F, Ungar P, Platt JA, González-Cabezas C, Eckert GJ, Hara AT. Tooth Age Impact on Dental Erosion Susceptibility and Treatment Efficacy. Caries Res 2021; 55:585-593. [PMID: 34610601 DOI: 10.1159/000519972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 09/28/2021] [Indexed: 11/19/2022] Open
Abstract
This laboratory study investigated the impact of tooth age on dental erosion susceptibility and preventive treatment efficacy. Extracted human premolars were selected and had their age estimated (∼10-100 years old) using established dental forensic methods. Enamel and root dentin slabs were prepared, embedded in acrylic blocks, flattened, and polished. The specimens were randomly assigned to one of three treatments (n = 93): Sn+F (800 ppm Sn as SnCl2 and 250 ppm F as NaF, pH 4.5), NaF (250 ppm F, pH 4.5), or deionized water (DIW). Each specimen was subjected for 10 days to a daily cycling protocol consisting of six 5-min erosive challenges (0.3% citric acid, pH 2.6), six 60-min remineralization periods (artificial saliva), and three 2-min treatments with the test solutions. Surface loss (SL) was measured after 3, 5, and 10 days, using optical profilometry. Effects of tooth age, antierosive treatment, and time on SL were evaluated using linear mixed effects regression analysis. SL increased with age for all substrate-treatment-time combinations (p < 0.0001). Sn+F and NaF solutions significantly reduced SL compared to DIW, regardless of substrate, time, or age (p < 0.0001), with best results shown for Sn+F. Efficacy of Sn+F increased with tooth age on enamel, but tooth age did not affect the efficacy of NaF on enamel. For dentin, increased efficacy was observed with age after 5 (for Sn+F) and 10 days (for Sn+F and NaF). In conclusion, increase of tooth age rendered enamel and root dentin more susceptible to dental erosion. NaF preventive efficacy improved with tooth age for dentin, in advanced erosion simulation. Sn+F reduced enamel SL due to erosion regardless of tooth age.
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Affiliation(s)
- Amnah A Algarni
- Department of Restorative Dentistry, College of Dentistry, Taibah University, Madina, Saudi Arabia
| | - Frank Lippert
- Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, Indianapolis, Indiana, USA
| | - Peter Ungar
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, USA
| | - Jeffrey A Platt
- Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, Indiana, USA
| | - Carlos González-Cabezas
- Department of Cariology, Restorative Sciences and Endodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan, USA
| | - George J Eckert
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Anderson T Hara
- Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, Indianapolis, Indiana, USA
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29
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Ishimoto T, Kawahara K, Matsugaki A, Kamioka H, Nakano T. Quantitative Evaluation of Osteocyte Morphology and Bone Anisotropic Extracellular Matrix in Rat Femur. Calcif Tissue Int 2021; 109:434-444. [PMID: 34009396 PMCID: PMC8429393 DOI: 10.1007/s00223-021-00852-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/16/2021] [Indexed: 12/22/2022]
Abstract
Osteocytes are believed to play a crucial role in mechanosensation and mechanotransduction which are important for maintenance of mechanical integrity of bone. Recent investigations have revealed that the preferential orientation of bone extracellular matrix (ECM) mainly composed of collagen fibers and apatite crystallites is one of the important determinants of bone mechanical integrity. However, the relationship between osteocytes and ECM orientation remains unclear. In this study, the association between ECM orientation and anisotropy in the osteocyte lacuno-canalicular system, which is thought to be optimized along with the mechanical stimuli, was investigated using male rat femur. The degree of ECM orientation along the femur longitudinal axis was significantly and positively correlated with the anisotropic features of the osteocyte lacunae and canaliculi. At the femur middiaphysis, there are the osteocytes with lacunae that highly aligned along the bone long axis (principal stress direction) and canaliculi that preferentially extended perpendicular to the bone long axis, and the highest degree of apatite c-axis orientation along the bone long axis was shown. Based on these data, we propose a model in which osteocytes can change their lacuno-canalicular architecture depending on the mechanical environment so that they can become more susceptible to mechanical stimuli via fluid flow in the canalicular channel.
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Affiliation(s)
- Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Keita Kawahara
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Aira Matsugaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Hiroshi Kamioka
- Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka, 565-0871, Japan.
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30
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Moriwaki K, Matsumoto H, Tanimura C, Osaki M, Nagashima H, Hagino H. Urinary pentosidine level is associated with grip strength and gait speed in community-dwelling adults: a cross-sectional study. BMC Musculoskelet Disord 2021; 22:392. [PMID: 33902533 PMCID: PMC8077690 DOI: 10.1186/s12891-021-04279-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 04/20/2021] [Indexed: 01/22/2023] Open
Abstract
Background Muscle and bone interactions might be associated with osteoporosis and sarcopenia. Urinary pentosidine and serum 25-hydroxyvitamin D (25(OH)D) might affect muscle and bone interactions. It is unclear whether these biomarkers are affected by age and sex or play a role in muscle and physical functions. We aimed to investigate the association between urinary pentosidine and serum 25(OH)D levels with muscle mass, muscle strength, and physical performance in community-dwelling adults. Methods Two-hundred and fifty-four middle-aged and elderly adults were enrolled. There was no significant difference in age between 97 men (75.0 ± 8.9 years) and 157 women (73.6 ± 8.1 years). The skeletal muscle mass index (SMI), grip strength, and gait speed were assessed. The urinary pentosidine level was measured. We evaluated the association of urinary pentosidine and serum 25(OH)D levels with age and sex (student’s t-test) and correlations between biomarker and each variable (Pearson’s correlation coefficients). Multiple regression analysis was performed with grip strength and gait speed as dependent variables and with age, height, weight, body mass index (BMI), speed of sound (SOS), SMI, glycated hemoglobin (HbA1c), estimated glomerular filtration rate (eGFR), 25(OH)D, and pentosidine as independent variables using the stepwise method. Results The urinary pentosidine level was negatively correlated with grip strength, gait speed, eGFR, and insulin-like growth factor-1 (IGF-1) in men and with SOS, grip strength, and gait speed in women. The serum 25(OH)D level was positively correlated with IGF-1 in women and grip strength in men. Grip strength was associated with age, height, and pentosidine in men and height and pentosidine in women. Gait speed was associated with age, BMI, and pentosidine in men and age, height, and pentosidine in women. Conclusion Urinary pentosidine levels are significantly associated with grip strength and gait speed and may serve as a biomarker of muscle and bone interactions.
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Affiliation(s)
- Kenta Moriwaki
- Department of Orthopedic Surgery, Faculty of Medicine, Tottori University, Nishicho 36-1, Yonago, Tottori, 683-8504, Japan. .,Department of Orthopedic Surgery, Misasa Onsen Hospital, Yamada 690Misasa, Tottori, 682-0122, Japan.
| | - Hiromi Matsumoto
- Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Matsushima 288, Kurashiki, Okayama, 701-0193, Japan
| | - Chika Tanimura
- School of Health Science, Faculty of Medicine, Tottori University, Nishicho 86, Yonago, Tottori, 683-8504, Japan
| | - Mari Osaki
- Rehabilitation Division, Tottori University Hospital, Nishicho 36-1, Yonago, Tottori, 683-8504, Japan
| | - Hideki Nagashima
- Department of Orthopedic Surgery, Faculty of Medicine, Tottori University, Nishicho 36-1, Yonago, Tottori, 683-8504, Japan
| | - Hiroshi Hagino
- School of Health Science, Faculty of Medicine, Tottori University, Nishicho 86, Yonago, Tottori, 683-8504, Japan.,Rehabilitation Division, Tottori University Hospital, Nishicho 36-1, Yonago, Tottori, 683-8504, Japan
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Melatonin-doped polymeric nanoparticles reinforce and remineralize radicular dentin: Morpho-histological, chemical and biomechanical studies. Dent Mater 2021; 37:1107-1120. [PMID: 33846017 DOI: 10.1016/j.dental.2021.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/15/2021] [Accepted: 03/28/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVES To investigate the effectiveness of novel polymeric nanoparticles (NPs) doped with melatonin (ML) in reducing dentin permeability and facilitating dentin remineralization after endodontic treatment. METHODS The effect of undoped NPs and ML-doped NPs (ML-NPs) was tested in radicular dentin, at 24 h and 6 m. A control group without NPs was included. ML liberation was measured. Radicular dentin was assessed for fluid filtration. Dentin remineralization was analyzed by scanning electron microscopy, AFM, Young's modulus (Ei), Nano DMA-tan delta, and Raman analysis. RESULTS ML release ranged from 1.85 mg/mL at 24 h to 0.033 mg/mL at 28 d. Both undoped NPs and ML-NPs treated dentin exhibited the lowest microleakage, but samples treated with ML-NPs exhibited hermetically sealed dentinal tubules and extended mineral deposits onto dentin. ML-NPs promoted higher and durable Ei, and functional remineralization at root dentin, generating differences between the values of tan delta among groups and creating zones of stress concentration. Undoped-NPs produced closure of some tubules and porosities at the expense of a relative mineral amorphization. Chemical remineralization based on mineral and organic assessments was higher in samples treated with ML-NPs. When using undoped NPs, precipitation of minerals occurred; however, radicular dentin was not mechanically reinforced but weakened over time. SIGNIFICANCE Application of ML-NPs in endodontically treated teeth, previous to the canal filling step, is encouraged due to occlusion of dentinal tubules and the reinforcement of the radicular dentin structure.
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Effect of Diabetes on Rotary Instrumentation of Dentin. J Endod 2021; 47:1301-1307. [DOI: 10.1016/j.joen.2021.03.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/16/2021] [Accepted: 03/31/2021] [Indexed: 12/18/2022]
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33
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Schuh CMAP, Benso B, Naulin PA, Barrera NP, Bozec L, Aguayo S. Modulatory Effect of Glycated Collagen on Oral Streptococcal Nanoadhesion. J Dent Res 2020; 100:82-89. [PMID: 32758105 DOI: 10.1177/0022034520946320] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Biofilm-mediated oral diseases such as dental caries and periodontal disease remain highly prevalent in populations worldwide. Biofilm formation initiates with the attachment of primary colonizers onto surfaces, and in the context of caries, the adhesion of oral streptococci to dentinal collagen is crucial for biofilm progression. It is known that dentinal collagen suffers from glucose-associated crosslinking as a function of aging or disease; however, the effect of collagen crosslinking on the early adhesion and subsequent biofilm formation of relevant oral streptococci remains unknown. Therefore, the aim of this work was to determine the impact of collagen glycation on the initial adhesion of primary colonizers such as Streptococcus mutans UA159 and Streptococcus sanguinis SK 36, as well as its effect on the early stages of streptococcal biofilm formation in vitro. Type I collagen matrices were crosslinked with either glucose or methylglyoxal. Atomic force microscopy nanocharacterization revealed morphologic and mechanical changes within the collagen matrix as a function of crosslinking, such as a significantly increased elastic modulus in crosslinked fibrils. Increased nanoadhesion forces were observed for S. mutans on crosslinked collagen surfaces as compared with the control, and retraction curves obtained for both streptococcal strains demonstrated nanoscale unbinding behavior consistent with bacterial adhesin-substrate coupling. Overall, glucose-crosslinked substrates specifically promoted the initial adhesion, biofilm formation, and insoluble extracellular polysaccharide production of S. mutans, while methylglyoxal treatment reduced biofilm formation for both strains. Changes in the adhesion behavior and biofilm formation of oral streptococci as a function of collagen glycation could help explain the biofilm dysbiosis seen in older people and patients with diabetes. Further studies are necessary to determine the influence of collagen crosslinking on the balance between acidogenic and nonacidogenic streptococci to aid in the development of novel preventive and therapeutic treatment against dental caries in these patients.
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Affiliation(s)
- C M A P Schuh
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - B Benso
- School of Dentistry, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - P A Naulin
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - N P Barrera
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - L Bozec
- Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - S Aguayo
- School of Dentistry, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.,Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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Park M, Islam S, Kim H, Korostoff J, Blatz MB, Hwang G, Kim A. Human Oral Motion-Powered Smart Dental Implant (SDI) for In Situ Ambulatory Photo-biomodulation Therapy. Adv Healthc Mater 2020; 9:e2000658. [PMID: 32613767 DOI: 10.1002/adhm.202000658] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/21/2020] [Indexed: 12/27/2022]
Abstract
Peri-implant disease is an inflammatory condition affecting the soft and hard tissues surrounding a dental implant. However, current preventative methods are insufficient due to the limited bioactivity on the dental implant and poor patient compliance. Recently, photo-biomodulation (PBM) therapy that can recover and regenerate peri-implant soft tissue has attracted considerable attention in dentistry. In this paper, a seamless human oral motion-powered dental implant system (called Smart Dental Implant or SDI) is presented as an ambulatory PBM therapy modality. SDI allows the in situ light delivery, which is enabled by the energy harvesting from dynamic human oral motions (chewing and brushing) via an engineered piezoelectric dental crown, an associated circuit, and micro light emitting diodes (LEDs). The SDI also offers adequate mechanical strength as the clinical standards. Using primary human gingival keratinocytes (HGKs) as a model host organism and Pseudomonas aeruginosa lipopolysaccharides (LPS) as a model inflammatory stimulus, effective SDI-mediated PBM therapy is demonstrated. A new class of dental implants could be an ambulatory PBM therapy platform for the prevention of peri-implant disease without patient dependency, warranting long-lasting dental implants.
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Affiliation(s)
- Moonchul Park
- Department of Electrical and Computer EngineeringTemple University Philadelphia PA 19122 USA
| | - Sayemul Islam
- Department of Electrical and Computer EngineeringTemple University Philadelphia PA 19122 USA
| | - Hye‐Eun Kim
- Department of Preventive and Restorative SciencesSchool of Dental MedicineUniversity of Pennsylvania Philadelphia PA 19104 USA
| | - Jonathan Korostoff
- Department of PeriodonticsSchool of Dental MedicineUniversity of Pennsylvania Philadelphia PA 19104 USA
| | - Markus B. Blatz
- Department of Preventive and Restorative SciencesSchool of Dental MedicineUniversity of Pennsylvania Philadelphia PA 19104 USA
| | - Geelsu Hwang
- Department of Preventive and Restorative SciencesSchool of Dental MedicineUniversity of Pennsylvania Philadelphia PA 19104 USA
- Center for Innovation & Precision DentistrySchool of Dental MedicineSchool of Engineering and Applied SciencesUniversity of Pennsylvania Philadelphia PA 19104 USA
| | - Albert Kim
- Department of Electrical and Computer EngineeringTemple University Philadelphia PA 19122 USA
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Kasahara M, Matsunaga S, Someya T, Kitamura K, Odaka K, Ishimoto T, Nakano T, Abe S, Hattori M. Micro- and nano-bone analyses of the human mandible coronoid process and tendon-bone entheses. J Biomed Mater Res B Appl Biomater 2020; 108:2799-2806. [PMID: 32190994 DOI: 10.1002/jbm.b.34609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 03/03/2020] [Accepted: 03/08/2020] [Indexed: 11/07/2022]
Abstract
The coronoid process provides attachment to temporalis and masseter muscles, and thus plays an important role in mastication. Tendons connect muscles and bones, mediating the transmission of functional loads to bones. Thus, tendon-bone entheses govern mechanical stress in bones. The preferential orientation of biological apatite (BAp) crystallites, the main mineral component in bones, is an important index for bone quality and function, and is largely influenced by locally applied stress. In this study, we analyzed BAp orientation, Young's modulus, and bone mineral density (BMD) at different sites in the human coronoid process. No differences in BMD were found among the analyzed sites, but BAp crystal orientation was observed to differ. BAp crystallites showed a uni-directional orientation in the mesiodistal direction at the coronoid process apex, but were oriented in the direction vertical to the occlusal plane at other sites. Young's modulus tended to vary according to the BAp orientation. At the apex, a tendon form with characteristics different from those at other sites, including the presence of a fibrocartilaginous layer that may act as a stretching brake to control stress concentration, was observed. These findings suggest that the functional pressure of the temporalis muscle affects bone quality and strength.
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Affiliation(s)
- Masaaki Kasahara
- Department of Dental Materials Science, Tokyo Dental College, Tokyo, Japan.,Oral Health Science Center, Tokyo Dental College, Tokyo, Japan
| | - Satoru Matsunaga
- Oral Health Science Center, Tokyo Dental College, Tokyo, Japan.,Department of Anatomy, Tokyo Dental College, Tokyo, Japan
| | - Tomoko Someya
- Department of Dental Materials Science, Tokyo Dental College, Tokyo, Japan
| | - Kei Kitamura
- Oral Health Science Center, Tokyo Dental College, Tokyo, Japan.,Department of Histology and Developmental Biology, Tokyo, Japan
| | - Kento Odaka
- Oral Health Science Center, Tokyo Dental College, Tokyo, Japan.,Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Shinichi Abe
- Department of Anatomy, Tokyo Dental College, Tokyo, Japan
| | - Masayuki Hattori
- Department of Dental Materials Science, Tokyo Dental College, Tokyo, Japan
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Alania Y, Trevelin LT, Hussain M, Zamperini CA, Mustafa G, Bedran-Russo AK. On the bulk biomechanical behavior of densely cross-linked dentin matrix: The role of induced-glycation, regional dentin sites and chemical inhibitor. J Mech Behav Biomed Mater 2020; 103:103589. [PMID: 32090918 PMCID: PMC7042333 DOI: 10.1016/j.jmbbm.2019.103589] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/17/2019] [Accepted: 12/07/2019] [Indexed: 10/25/2022]
Abstract
Collagen glycation takes place under physiological conditions during chronological aging, leading to the formation of advanced glycation end-products (AGEs). AGEs accumulation induces non-enzymatic collagen cross-links increasing tissue stiffness and impairing function. Here, we focused on determining the cumulative effect of induced glycation on the mechanical behavior of highly collagen cross-linked dentin matrices and assess the topical inhibition potential of aminoguanidine. Bulk mechanical characterization suggests that early glycation cross-links significantly increase the tensile strength and stiffness of the dentin matrix and promote a brittle failure response. Histologically, glycation yielded a more mature type I collagen in a densely packed collagen matrix. The time-dependent effect of glycation indicates cumulative damage of dentin matrices that is partially inhibited by aminoguanidine. The regional dentin sites were differently affected by induced-glycation, revealing the crown dentin to be mechanically more affected by the glycation protocol. These findings in human dentin set the foundation for the proposed in vitro ribose-induced glycation model, which produces an early matrix stiffening mechanism by reducing tissue viscoelasticity and can be partially inhibited by topical aminoguanidine.
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Affiliation(s)
- Yvette Alania
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL, 60612, USA
| | - Livia T Trevelin
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL, 60612, USA; Department of Restorative Dentistry, School of Dentistry, University of São Caetano Do Sul, Rua Santo Antônio 50, São Caetano Do Sul, São Paulo, 09521-160, Brazil
| | - Mohammad Hussain
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL, 60612, USA
| | - Camila A Zamperini
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL, 60612, USA
| | - Gresa Mustafa
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL, 60612, USA
| | - Ana K Bedran-Russo
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina St, Chicago, IL, 60612, USA.
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Toledano M, Osorio E, Aguilera FS, Muñoz-Soto E, Toledano-Osorio M, López-López MT, Medina-Castillo AL, Carrasco-Carmona Á, Osorio R. Polymeric nanoparticles for endodontic therapy. J Mech Behav Biomed Mater 2019; 103:103606. [PMID: 32090933 DOI: 10.1016/j.jmbbm.2019.103606] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 11/16/2022]
Abstract
The effectiveness of novel polymeric nanoparticles (NPs) application in reducing dentin permeability and facilitating dentin remineralization after endodontic treatment was evaluated. The effect of undoped NPs, zinc, calcium and doxycycline-doped NPs (Zn-NPs, Ca-NPs and D-NPs, respectively) was tested in radicular dentin. A control group without NPs was included. Radicular dentin was assessed for fluid filtration. Dentin remineralization was analyzed by scanning and transmission electron microscopy, energy-dispersive analysis, AFM, Young's modulus (Ei), Nano DMA, Raman, and X-Ray Diffraction analysis. Ca-NPs and Zn-NPs treated dentin exhibited the lowest microleakage with hermetically sealed dentinal tubules and a zinc-based salt generation onto dentin. Zn-NPs favored crystallinity and promoted the highest Ei and functional remineralization at the apical dentin, generating differences between the values of complex modulus among groups. Ca-NPs produced closure of tubules and porosities at the expense of a relative mineral amorphization, without creating zones of stress concentration. The highest sealing efficacy was obtained in Zn-NPs-treated samples, along with the highest values of Young's modulus and dentin mineralization. These high values of Ei were obtained by closing voids, cracks, pores and tubules, and by strengthening the root dentin. When using undoped NPs or Ca-NPs, deposition of minerals occurred, but radicular dentin was not mechanically reinforced. Therefore, application of Zn-NPs in endodontically treated teeth previous to the canal filling is encouraged.
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Affiliation(s)
- Manuel Toledano
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja S/n, Granada, 18071, Spain
| | - Estrella Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja S/n, Granada, 18071, Spain
| | - Fátima S Aguilera
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja S/n, Granada, 18071, Spain
| | - Esther Muñoz-Soto
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja S/n, Granada, 18071, Spain
| | - Manuel Toledano-Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja S/n, Granada, 18071, Spain.
| | - Modesto T López-López
- University of Granada, Faculty of Science, Applied Physics Department, Fuente Nueva S/n, Granada, 18071, Spain
| | - Antonio L Medina-Castillo
- NanoMyP, Spin-Off Enterprise from University of Granada, Edificio BIC-Granada, Avda. Innovación 1, Armilla, Granada, 18016, Spain
| | - Álvaro Carrasco-Carmona
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja S/n, Granada, 18071, Spain
| | - Raquel Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja S/n, Granada, 18071, Spain
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Ishimoto T, Suetoshi R, Cretin D, Hagihara K, Hashimoto J, Kobayashi A, Nakano T. Quantitative ultrasound (QUS) axial transmission method reflects anisotropy in micro-arrangement of apatite crystallites in human long bones: A study with 3-MHz-frequency ultrasound. Bone 2019; 127:82-90. [PMID: 31170537 DOI: 10.1016/j.bone.2019.05.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/20/2019] [Accepted: 05/26/2019] [Indexed: 10/26/2022]
Abstract
Anisotropic arrangement of apatite crystallites, i.e., preferential orientation of the apatite c-axis, is known to be an important bone quality parameter that governs the mechanical properties. However, noninvasive evaluation of apatite orientation has not been achieved to date. The present paper reports the potential of quantitative ultrasound (QUS) for noninvasive evaluation of the degree of apatite orientation in human bone for the first time. A novel QUS instrument for implementation of the axial transmission (AT) method is developed, so as to achieve precise measurement of the speed of sound (SOS) in the cortex (cSOS) of human long bone. The advantages of our QUS instrument are the following: (i) it is equipped with a cortical bone surface-morphology detection system to correct the ultrasound transmission distance, which should be necessary for AT measurement of long bone covered by soft tissue of non-uniform thickness; and (ii) ultrasound with a relatively high frequency of 3 MHz is employed, enabling thickness-independent cSOS measurement even for the thin cortex by preventing guide wave generation. The reliability of the proposed AT measurement system is confirmed through comparison with the well-established direct transmission (DT) method. The cSOS in human long bone is found to exhibit considerable direction-dependent anisotropy; the axial cSOS (3870 ± 66 m/s) is the highest, followed by the tangential (3411 ± 94 m/s) and radial (3320 ± 85 m/s) cSOSs. The degree of apatite orientation exhibits the same order, despite the unchanged bone mineral density. Multiple regression analysis reveals that the cSOS of human long bone strongly reflects the apatite orientation. The cSOS determined by the AT method is positively correlated with that determined by the DT method and sensitively reflects the apatite orientation variation, indicating the validity of the AT instrument developed in this study. Our instrument will be beneficial for noninvasive evaluation of the material integrity of the human long-bone cortex, as determined by apatite c-axis orientation along the axial direction.
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Affiliation(s)
- Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan
| | - Ryoichi Suetoshi
- Research and Innovation Center, Furuno Electric Co., Ltd., 9-52, Ashihara-cho, Nishinomiya, Hyogo 662-8580, Japan
| | - Dorian Cretin
- Research and Innovation Center, Furuno Electric Co., Ltd., 9-52, Ashihara-cho, Nishinomiya, Hyogo 662-8580, Japan
| | - Koji Hagihara
- Department of Adaptive Machine Systems, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan
| | - Jun Hashimoto
- Department of Rheumatology, National Hospital Organization, Osaka-Minami Medical Center, 2-1 Kidohigashi, Kawachinagano, Osaka 586-8521, Japan
| | - Akio Kobayashi
- Department of Orthopaedic Surgery, Shiraniwa Hospital Joint Arthroplasty Center, 6-10-1 Shiraniwadai Ikoma, Nara 630-0136, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan.
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Toledano M, Muñoz-Soto E, Aguilera FS, Osorio E, González-Rodríguez MP, Pérez-Álvarez MC, Toledano-Osorio M, Osorio R. A zinc oxide-modified hydroxyapatite-based cement favored sealing ability in endodontically treated teeth. J Dent 2019; 88:103162. [DOI: 10.1016/j.jdent.2019.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/10/2019] [Accepted: 06/27/2019] [Indexed: 01/16/2023] Open
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UVA-activated riboflavin promotes collagen crosslinking to prevent root caries. Sci Rep 2019; 9:1252. [PMID: 30718745 PMCID: PMC6362121 DOI: 10.1038/s41598-018-38137-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 12/13/2018] [Indexed: 11/09/2022] Open
Abstract
Root caries is an increasingly problem in aging societies with severe implications for the general health and wellbeing of large numbers of people. Strengthening type-I collagen, a major organic component of human dentin, has proved effective in preventing root caries. This study sought to determine whether exposure to riboflavin followed by UVA irradiation (RF/UVA) could promote additional collagen crosslinking, and thus improve the acid and enzymatic resistance of human dentin under simulated oral environments. If so, it could offer potential for treatment of the intractable problem of root caries. The greatest flexural strengths were found in dentin exposed to a 0.1% riboflavin solution for 1 minute followed by 1,600 mW/cm2 UVA irradiation for 10 minutes. Mineral loss and lesion depth were significantly lower in the RF/UVA group than in the control group. The microstructures of dentinal tubules and collagen networks after RF/UVA treatment retained their original forms after acidic and enzymatic degradation. In conclusion, RF/UVA treatment may be a new method for preventing root caries with promising prospects for clinical application.
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41
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Toledano M, Osorio E, Aguilera FS, Toledano-Osorio M, López-López MT, Osorio R. Stored potential energy increases and elastic properties alterations are produced after restoring dentin with Zn-containing amalgams. J Mech Behav Biomed Mater 2018; 91:109-121. [PMID: 30553207 DOI: 10.1016/j.jmbbm.2018.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/27/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022]
Abstract
The aim of this research was to ascertain the mechanical and chemical behavior of sound and caries-affected dentin (CAD), after the placement of Zn-free vs containing amalgam restorations. Peritubular and intertubular dentin were evaluated using, a) nanoindenter in scanning mode; the load and displacement responses were used to perform the nano-Dynamic mechanical analysis and to estimate the complex (E * ) and storage modulus (E'); b) Raman spectroscopy was used to describe the hierarchical cluster analysis (HCA). Assessments were performed before restoration placement and after restoring, and after 3 months of storage with thermocycling (100,000cy/5 °C and 55 °C). When CAD was treated with Zn-containing restorations, differences between E * and E' at both peritubular and intertubular dentin augmented, with energy concentration and production of implications in the mechanical performance of the restored teeth. E * and E' were very low at intratubular dentin of CAD restored with Zn-containing restorations. The relative presence of minerals, the phosphate crystallinity and the crosslinking of collagen increased their values at both types of dentin (peritubular and intertubular) when CAD was treated with Zn-containing restorations. The nature and secondary structure of collagen improved in CAD treated with Zn-containing amalgams. Different levels of dentin remineralization were revealed by hierarchical cluster analysis.
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Affiliation(s)
- Manuel Toledano
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain.
| | - Estrella Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain
| | - Fátima S Aguilera
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain
| | - Manuel Toledano-Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain
| | - Modesto T López-López
- University of Granada, Faculty of Science, Applied Physics Department, Fuente Nueva s/n, 18071 Granada, Spain
| | - Raquel Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain
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Toledano M, Osorio R, Pérez-Álvarez MC, Osorio E, Lynch CD, Toledano-Osorio M. A zinc-doped endodontic cement facilitates functional mineralization and stress dissipation at the dentin surface. Med Oral Patol Oral Cir Bucal 2018; 23:e646-e655. [PMID: 30341273 PMCID: PMC6260998 DOI: 10.4317/medoral.22751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 09/07/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The purpose of this study was to evaluate nanohardness and viscoelastic behavior of dentin surfaces treated with two canal sealer cements for dentin remineralization. MATERIAL AND METHODS Dentin surfaces were subjected to: i) 37% phosphoric acid (PA) or ii) 0.5 M ethylenediaminetetraacetic acid (EDTA) conditioning prior to the application of two experimental hydroxyapatite-based cements, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite), respectively. Samples were stored in simulated body fluid during 24 h or 21 d. The intertubular and peritubular dentin were evaluated using a nanoindenter to assess nanohardness (Hi). The load/displacement responses were used for the nano-dynamic mechanical analysis to estimate complex modulus (E*) and tan delta (δ). The modulus mapping was obtained by imposing a quasistatic force setpoint to which a sinusoidal force was superimposed. AFM imaging and FESEM analysis were performed. RESULTS After 21 d of storage, dentin surfaces treated with EDTA+calcypatite, PA+calcypatite and EDTA+oxipatite showed viscoelastic discrepancies between peritubular and intertubular dentin, meaning a risk for cracking and breakdown of the surface. At both 24 h and 21 d, tan δ values at intertubular dentin treated with the four treatments performed similar. At 21 d time point, intertubular dentin treated with PA+oxipatite achieved the highest complex modulus and nanohardness, i.e., highest resistance to deformation and functional mineralization, among groups. CONCLUSIONS Intertubular and peritubular dentin treated with PA+oxipatite showed similar values of tan δ after 21 d of storage. This produced a favorable dissipation of energy with minimal energy concentration, preserving the structural integrity at the dentin surface.
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Affiliation(s)
- M Toledano
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 - Granada - Spain,
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Todhunter ME, Sayaman RW, Miyano M, LaBarge MA. Tissue aging: the integration of collective and variant responses of cells to entropic forces over time. Curr Opin Cell Biol 2018; 54:121-129. [PMID: 29908481 PMCID: PMC6258070 DOI: 10.1016/j.ceb.2018.05.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/13/2018] [Accepted: 05/30/2018] [Indexed: 01/08/2023]
Abstract
Aging is driven by unavoidable entropic forces, physicochemical in nature, that damage the raw materials that constitute biological systems. Single cells experience and respond to stochastic physicochemical insults that occur either to the cells themselves or to their microenvironment, in a dynamic and reciprocal manner, leading to increased age-related cell-to-cell variation. We will discuss the biological mechanisms that integrate cell-to-cell variation across tissues resulting in stereotypical phenotypes of age.
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Affiliation(s)
- Michael E Todhunter
- Department of Populations Sciences, and Center for Cancer and Aging, Beckman Research Institute at City of Hope, 1500 E Duarte Rd, Duarte, CA 91011 USA
| | - Rosalyn W Sayaman
- Department of Populations Sciences, and Center for Cancer and Aging, Beckman Research Institute at City of Hope, 1500 E Duarte Rd, Duarte, CA 91011 USA
| | - Masaru Miyano
- Department of Populations Sciences, and Center for Cancer and Aging, Beckman Research Institute at City of Hope, 1500 E Duarte Rd, Duarte, CA 91011 USA
| | - Mark A LaBarge
- Department of Populations Sciences, and Center for Cancer and Aging, Beckman Research Institute at City of Hope, 1500 E Duarte Rd, Duarte, CA 91011 USA.
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Ilea A, Băbţan AM, Boşca BA, Crişan M, Petrescu NB, Collino M, Sainz RM, Gerlach JQ, Câmpian RS. Advanced glycation end products (AGEs) in oral pathology. Arch Oral Biol 2018; 93:22-30. [DOI: 10.1016/j.archoralbio.2018.05.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 04/07/2018] [Accepted: 05/17/2018] [Indexed: 02/08/2023]
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Valenzuela A, Guerra-Hernández E, Rufián-Henares JÁ, Márquez-Ruiz AB, Hougen HP, García-Villanova B. Differences in non-enzymatic glycation products in human dentine and clavicle: changes with aging. Int J Legal Med 2018; 132:1749-1758. [DOI: 10.1007/s00414-018-1908-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 07/26/2018] [Indexed: 01/22/2023]
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Abstract
This article provides a brief review of recent investigations concerning the structure and properties of the tooth. The last decade has brought a greater emphasis on the durability of the tooth, an improved understanding of the fatigue and fracture behavior of the principal tissues, and their importance to tooth failures. The primary contributions to tooth durability are discussed, including the process of placing a restoration, the impact of aging, and challenges posed by the oral environment. The significance of these findings to the dental community and their importance to the pursuit of lifelong oral health are highlighted.
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Affiliation(s)
- Dwayne D Arola
- Department of Materials Science and Engineering, University of Washington School of Dentistry, Roberts Hall, 333, Box 352120, Seattle, WA 98195-2120, USA; Department of Oral Health Sciences, University of Washington School of Dentistry, Seattle, WA 98195-2120, USA; Department of Restorative Dentistry, Box 357456, University of Washington School of Dentistry, Seattle, WA 98195-7456, USA.
| | - Shanshan Gao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Renmin South Road, Chengdu, 610041, China
| | - Hai Zhang
- Department of Restorative Dentistry, Box 357456, University of Washington School of Dentistry, Seattle, WA 98195-7456, USA
| | - Radi Masri
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, 650 West Baltimore Street, 4th Floor, Suite 4228, Baltimore, MD 21201, USA
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Toledano-Osorio M, Osorio E, Aguilera FS, Luis Medina-Castillo A, Toledano M, Osorio R. Improved reactive nanoparticles to treat dentin hypersensitivity. Acta Biomater 2018; 72:371-380. [PMID: 29581027 DOI: 10.1016/j.actbio.2018.03.033] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 03/02/2018] [Accepted: 03/19/2018] [Indexed: 12/30/2022]
Abstract
The aim of this study was to evaluate the effectiveness of different nanoparticles-based solutions for dentin permeability reduction and to determine the viscoelastic performance of cervical dentin after their application. Four experimental nanoparticle solutions based on zinc, calcium or doxycycline-loaded polymeric nanoparticles (NPs) were applied on citric acid etched dentin, to facilitate the occlusion and the reduction of the fluid flow at the dentinal tubules. After 24 h and 7 d of storage, cervical dentin was evaluated for fluid filtration. Field emission scanning electron microscopy, energy dispersive analysis, AFM and Nano-DMA analysis were also performed. Complex, storage, loss modulus and tan delta (δ) were assessed. Doxycycline-loaded NPs impaired tubule occlusion and fluid flow reduction trough dentin. Tubules were 100% occluded in dentin treated with calcium-loaded NPs or zinc-loaded NPs, analyzed at 7 d. Dentin treated with both zinc-NPs and calcium-NPs attained the highest reduction of dentinal fluid flow. Moreover, when treating dentin with zinc-NPs, complex modulus values attained at intertubular and peritubular dentin were higher than those obtained after applying calcium-NPs. Zinc-NPs are then supposed to fasten active dentin remodeling, with increased maturity and high mechanical properties. Zinc-based nanoparticles are then proposed for effective dentin remineralization and tubular occlusion. Further research to finally prove for clinical benefits in patients with dentin hypersensitivity using Zn-doped nanoparticles is encouraged. STATEMENT OF SIGNIFICANCE Erosion from acids provokes dentin hypersensitivity (DH) which presents with intense pain of short duration. Open dentinal tubules and demineralization favor DH. Nanogels based on Ca-nanoparticles and Zn-nanoparticles produced an efficient reduction of fluid flow. Dentinal tubules were filled by precipitation of induced calcium-phosphate deposits. When treating dentin with Zn-nanoparticles, complex modulus values attained at intertubular and peritubular dentin were higher than those obtained after applying Ca-nanoparticles. Zn-nanoparticles are then supposed to fasten active dentin remodeling, with increased maturity and high mechanical properties. Zinc-based nanogels are, therefore, proposed for effective dentin remineralization and tubular occlusion. Further research to finally prove for clinical benefits in patients with dentin hypersensitivity using Zn-doped nanogels is encouraged.
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Pollaris E, Haspeslagh M, Van den Wyngaert G, Vlaminck L. Equine cheek teeth occlusal fissures: Prevalence, association with dental wear abnormalities and occlusal angles. Equine Vet J 2018; 50:787-792. [PMID: 29509311 DOI: 10.1111/evj.12828] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 02/26/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND Fissures of the occlusal surface of equine cheek teeth are commonly encountered during oral examination but their aetiology is unknown. OBJECTIVES To examine the prevalence and characteristics of occlusal fissures in cadaver teeth. It is hypothesised that their prevalence is influenced by masticatory forces. Consequently, their possible association with wear disorders and occlusal angles were examined. STUDY DESIGN Cross-sectional survey. METHODS The dental abnormalities and occlusal fissure findings in the cheek teeth of 143 cadaver heads were recorded. The cheek teeth occlusal angles were measured using the stiff-hinge technique. Multiple regression analyses were performed to establish possible relationships between age, sex, dental wear, occlusal angle and fissure prevalence. RESULTS Occlusal fissures were found in 103/143 (72%) heads. Sex and age were determining factors in the prevalence of fissures. A similar prevalence was found in mandibular (54.1%) and maxillary teeth (45.9%, OR = 1.10; 95% CI = 0.95-1.29, P = 0.2). Mandibular fissures were more commonly located on the buccal aspect (OR = 1.42; 95% CI = 1.16-1.65, P < 0.001), whereas for maxillary fissures there was no difference in prevalence between palatal and buccal aspects (OR = 1.19; 95% CI = 0.97-1.46, P = 0.1). Two main fissure types were identified. Type 1a fissures were the most prevalent type (39.5%). No significant correlation was found between the presence of wear abnormalities or the occlusal angle of cheek teeth, and the prevalence of fissures. MAIN LIMITATIONS No dental histories were available. CONCLUSION Equine cheek teeth show a high prevalence of occlusal fissures. Despite some evidence of predilection sites on the tooth surface that might indicate a mechanical aetiology for these lesions, no associations were found with wear abnormalities or occlusal angles of affected cheek teeth. Further histological and ultrastructural studies are warranted to elucidate their aetiology and possible role in other dental diseases.
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Affiliation(s)
- E Pollaris
- Department of Surgery and Anaesthesiology of Large Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - M Haspeslagh
- Department of Surgery and Anaesthesiology of Large Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - G Van den Wyngaert
- Department of Surgery and Anaesthesiology of Large Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - L Vlaminck
- Department of Surgery and Anaesthesiology of Large Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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Breschi L, Maravic T, Cunha SR, Comba A, Cadenaro M, Tjäderhane L, Pashley DH, Tay FR, Mazzoni A. Dentin bonding systems: From dentin collagen structure to bond preservation and clinical applications. Dent Mater 2018; 34:78-96. [DOI: 10.1016/j.dental.2017.11.005] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 11/10/2017] [Indexed: 12/18/2022]
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Yan W, Montoya C, Øilo M, Ossa A, Paranjpe A, Zhang H, Arola D. Reduction in Fracture Resistance of the Root with Aging. J Endod 2017; 43:1494-1498. [DOI: 10.1016/j.joen.2017.04.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 04/17/2017] [Accepted: 04/20/2017] [Indexed: 11/25/2022]
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