1
|
Kintopp CCDA, Diógenes AN, Lopes RT, Weber KR, Rezende CEE, Kaizer MDR, Gonzaga CC. Stress distribution on teeth restored with veneers using various incisal preparation designs: A 3D finite element analysis study. J Prosthet Dent 2024; 131:1159.e1-1159.e10. [PMID: 38580583 DOI: 10.1016/j.prosdent.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 04/07/2024]
Abstract
STATEMENT OF PROBLEM The type of veneer preparation is often chosen according to the patient's tooth structure and occlusion. Taking biomechanics into account in this decision-making process provides the clinician with more technical information on how to improve the clinical longevity of restorations. However, biomechanical analyses of veneer preparation designs are sparse. PURPOSE The purpose of this 3-dimensional (3D) finite element analysis with microcomputed tomography (µCT) data obtained from realistic models was to assess the influence of different preparations for ceramic and composite resin veneers on restoration and resin layer stress distribution. MATERIAL AND METHODS Four replicas of a central incisor were printed and prepared for laminate veneers with 4 different incisal edge designs: shoulder (SH), palatal chamfer (PC), palatal chamfer and oblique fracture involving the distal angle (OF-PC), and palatal chamfer involving horizontal incisal fracture (IF-PC). After fabrication and cementation of the veneers, the restored replicas were assessed with µCT, and 3D finite element models were built. A 100-N load was applied on the palatal surface at 60 and 125 degrees relative to the longitudinal axis. Maximum principal stress and stress distribution on the veneers, cement layer, and tooth structure were calculated and analyzed. RESULTS The SH preparation exhibited better stress distribution than the PC preparation, and the cement layer and the veneer were subjected to lower stress. The IF-PC preparation had better stress distribution than the OF-PC. The shoulder and IF-PC showed higher stress on laminate veneers, but lower stress on the cement layer. Ceramic veneers exhibited lower stress than composite resin veneers. CONCLUSIONS The different incisal preparations for laminate veneers influenced stress distribution on restorations and on the resin cement layer. The shoulder type preparation showed better stress distribution and the composite resin veneers showed unfavorable results compared with the ceramic veneers.
Collapse
Affiliation(s)
| | - Alysson Nunes Diógenes
- Professor, Department of Mechanical Engineering, Positivo University (UP), Curitiba, Brazil
| | - Ricardo Tadeu Lopes
- Researcher, Nuclear Engineering Program, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Katia Raquel Weber
- Postdoctoral fellow, Graduate Program in Dentistry, School of Health Sciences, Positivo University (UP), Curitiba, Brazil
| | | | - Marina da Rosa Kaizer
- Professor, Graduate Program in Dentistry, School of Health Sciences, Positivo University (UP), Curitiba, Brazil
| | - Carla Castiglia Gonzaga
- Professor, Graduate Program in Dentistry, School of Health Sciences, Positivo University (UP), Curitiba, Brazil.
| |
Collapse
|
2
|
Degli Esposti L, Ionescu AC, Gandolfi S, Ilie N, Adamiano A, Brambilla E, Iafisco M. Natural, biphasic calcium phosphate from fish bones for enamel remineralization and dentin tubules occlusion. Dent Mater 2024; 40:593-607. [PMID: 38365457 DOI: 10.1016/j.dental.2024.02.019] [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: 10/23/2023] [Revised: 02/02/2024] [Accepted: 02/12/2024] [Indexed: 02/18/2024]
Abstract
OBJECTIVES A calcium phosphate extracted from fish bones (CaP-N) was evaluated for enamel remineralization and dentinal tubules occlusion. METHODS CaP-N was characterized by assessing morphology by SEM, crystallinity by PXRD, and composition by ICP-OES. CaP-N morphology, crystallinity, ion release, and pH changes over time in neutral and acidic solutions were studied. CaP-N was then tested to assess remineralization and dentinal tubules occlusion on demineralized human enamel and dentin specimens (n = 6). Synthetic calcium phosphate in form of stoichiometric hydroxyapatite nanoparticles (CaP-S) and tap water were positive and negative controls, respectively. After treatment (brush every 12 h for 5d and storage in Dulbecco's modified PBS), specimens' morphology and surface composition were assessed (by SEM-EDS), while the viscoelastic behavior was evaluated with microindentation and DMA. RESULTS CaP-N consisted of rounded microparticles (200 nm - 1 µm) composed of 33 wt% hydroxyapatite and 67 wt% β-tricalcium phosphate. In acidic solution, CaP-N released calcium and phosphate ions thanks to the preferential β-tricalcium phosphate phase dissolution. Enamel remineralization was induced by CaP-N comparably to CaP-S, while CaP-N exhibited a superior dentinal tubule occlusion than CaP-S, forming mineral plugs and depositing new nanoparticles onto demineralized collagen. This behavior was attributed to its bigger particle size and increased solubility. DMA depth profiling and SEM showed an excellent interaction between the newly formed mineralized structures and the pristine tissue, particularly at the exposed collagen fibrils. SIGNIFICANCE CaP-N demonstrated very good remineralizing and occlusive activity in vitro, comparable to CaP-S, thus could be a promising circular economy alternative therapeutic agent for dentistry.
Collapse
Affiliation(s)
- Lorenzo Degli Esposti
- Institute of Science, Technology and Sustainability for Ceramics (ISSMC), National Research Council (CNR), Via Granarolo 64, 48018 Faenza, Italy
| | - Andrei C Ionescu
- Oral Microbiology and Biomaterials Laboratory, Department of Biomedical, Surgical, and Dental Sciences, University of Milan, Via Pascal, 36, 20133 Milan, Italy; Ospedale Maggiore Policlinico, Fondazione IRCCS Cà Granda, Milan 20100, Italy
| | - Sara Gandolfi
- Institute of Science, Technology and Sustainability for Ceramics (ISSMC), National Research Council (CNR), Via Granarolo 64, 48018 Faenza, Italy; Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Parco Area delle Scienze 17/A, 43124 Parma, Italy
| | - Nicoleta Ilie
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University, Goethestr. 70, 80336 Munich, Germany
| | - Alessio Adamiano
- Institute of Science, Technology and Sustainability for Ceramics (ISSMC), National Research Council (CNR), Via Granarolo 64, 48018 Faenza, Italy
| | - Eugenio Brambilla
- Oral Microbiology and Biomaterials Laboratory, Department of Biomedical, Surgical, and Dental Sciences, University of Milan, Via Pascal, 36, 20133 Milan, Italy
| | - Michele Iafisco
- Institute of Science, Technology and Sustainability for Ceramics (ISSMC), National Research Council (CNR), Via Granarolo 64, 48018 Faenza, Italy.
| |
Collapse
|
3
|
Zhou Z, Guo D, Watts DC, Fischer NG, Fu J. Application and limitations of configuration factor (C-factor) in stress analysis of dental restorations. Dent Mater 2023; 39:1137-1149. [PMID: 37838610 DOI: 10.1016/j.dental.2023.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 10/16/2023]
Abstract
OBJECTIVE The configuration factor (C-factor) is an index used to evaluate the relationship between cavity configuration and the development of polymerization shrinkage stress in dental restorations. Although C-factor has been widely researched, its correlation with stress analysis in dental restorations remains controversial. This review aims to discuss the application and limitations of C-factor and define the restricted conditions under which the C-factor "rule of thumb" is applicable. METHODS A thorough literature review was conducted on the application and limitations of C-factor in stress analysis of dental restorations. This was principally based on MEDLINE/PubMed and Web of Science databases and a review of the relevant studies and publications in scientific papers in international peer-reviewed journals for the specific topic of C-factor and polymerization shrinkage. RESULTS The C-factor alone cannot provide an accurate prediction of the shrinkage stress of restorations and the mechanical behavior of material-tooth interfaces. C-factor is only applicable under one condition not typically seen in clinical practice: low, near-rigid compliance. SIGNIFICANCE Conditions for the application of C-factor have been explicitly defined. A more accurate and precise understanding and utilization of the C-factor is of benefit as it contributes to better understanding of polymerization shrinkage behavior of restorations.
Collapse
Affiliation(s)
- Zixuan Zhou
- Department of Prosthodontics, The Affiliated Hospital of Qingdao University, 266000 Qingdao, China; School of Stomatology of Qingdao University, 266003 Qingdao, China
| | - Di Guo
- Department of Prosthodontics, The Affiliated Hospital of Qingdao University, 266000 Qingdao, China; School of Stomatology of Qingdao University, 266003 Qingdao, China
| | - David C Watts
- University of Manchester, School of Medical Sciences, Oxford Road, M13 9PL Manchester, UK
| | - Nicholas G Fischer
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Jing Fu
- Department of Prosthodontics, The Affiliated Hospital of Qingdao University, 266000 Qingdao, China; School of Stomatology of Qingdao University, 266003 Qingdao, China.
| |
Collapse
|
4
|
Călinoiu ȘG, Bîcleșanu C, Florescu A, Stoia DI, Dumitru C, Miculescu M. Comparative Study on Interface Fracture of 4th Generation 3-Steps Adhesive and 7th Generation Universal Adhesive. MATERIALS (BASEL, SWITZERLAND) 2023; 16:5834. [PMID: 37687525 PMCID: PMC10488864 DOI: 10.3390/ma16175834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/17/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023]
Abstract
The purpose of this paper is to compare the fracture behavior of interfaces obtained using fourth-generation and universal dental adhesives. The study relies on optic and SEM to evaluate the dentin-adhesive-restoration material interface of the samples and also on FEA simulation of fracture behavior. Specimen fabrication relied on 20 extracted teeth, in which class I cavities were created according to a protocol established based on the rules of minimally invasive therapy. For the direct adhesive technique, the adhesives used were: three-step All Bond, three-batch A and one-step Clearfil Universal Bond Quick-batch B. The restoration was performed with the same composite for both adhesives: Gradia direct posterior. The simulation used a 3D reconstructed molar on which geometric operations were performed to obtain an assembly that replicated a physical specimen. Material properties were applied to each component based on the information found in the literature. A simplified model for crack propagation was constructed, and using the fracture mechanics tool in Ansys 2019, the stress intensity factors that act at the crack tip of the adhesive interface were obtained. Mechanical simulation and microscopic investigation showed us how the interface of the dentine-adhesive-filling material performed in cases of both dental adhesives and for a certain loading condition. Important differences were identified among the adhesives, the fourth generation being superior to the fourth generation especially due to the separate steps in which the tooth surface was prepared for adhesion.
Collapse
Affiliation(s)
- Ștefan George Călinoiu
- Doctoral School of Dentistry, Organizing Institution of University Doctoral Studies, “Titu Maiorescu” University, 67A Gh. Petrascu Street, 040441 Bucharest, Romania;
| | - Cornelia Bîcleșanu
- Faculty of Dental Medicine, “Titu Maiorescu” University, 67A Gh. Petrascu Street, 040441 Bucharest, Romania; (C.B.); (C.D.)
| | - Anamaria Florescu
- Faculty of Dental Medicine, “Titu Maiorescu” University, 67A Gh. Petrascu Street, 040441 Bucharest, Romania; (C.B.); (C.D.)
| | - Dan Ioan Stoia
- Department of Mechanics and Strength of Materials, Faculty of Mechanical Engineering, Politehnica University of Timisoara, No.1 Mihai Viteazu Avenue, 300222 Timisoara, Romania
| | - Cătălin Dumitru
- Faculty of Dental Medicine, “Titu Maiorescu” University, 67A Gh. Petrascu Street, 040441 Bucharest, Romania; (C.B.); (C.D.)
| | - Marian Miculescu
- Faculty of Material Science and Engineering, Politehnica University of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania;
| |
Collapse
|
5
|
Toledano M, Osorio E, Osorio MT, Aguilera FS, Toledano R, Romero EF, Osorio R. Dexamethasone-doped nanoparticles improve mineralization, crystallinity and collagen structure of human dentin. J Dent 2023; 130:104447. [PMID: 36754111 DOI: 10.1016/j.jdent.2023.104447] [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: 11/07/2022] [Revised: 02/01/2023] [Accepted: 02/04/2023] [Indexed: 02/09/2023] Open
Abstract
OBJECTIVES Bioactive materials have been used for functionalization of adhesives to promote dentin remineralization. This study aims to evaluate bonding ability and both mechanical and chemical behavior of demineralized dentin infiltrated with polymeric nanoparticles doped with dexamethasone (Dex-NPs). METHODS Dentin conditioned surfaces were infiltrated with NPs, Dex-NPs or Dex-Zn-NPs. Bonded interfaces were also created and stored for 24 h or 21d, and then submitted to microtensile bond strength testing. Dentin remineralization was analyzed by Nanohardness, Young's modulus and Raman analysis. RESULTS At 21d of storage, dentin treated with undoped-NPs attained the lowest nanohardness and Young's modulus. Dex-NPs and Zn-Dex-NPs increased dentin nanohardness and Young's modulus after 21d Raman analysis showed high remineralization, crystallinity, crosslinking and better structure of collagen when functionalized Dex-NPs were present at the dentin interface. CONCLUSIONS Infiltration of dentin with Dex-NPs promoted functional remineralization as proved by nanomechanical and morpho-chemical evaluation tests. Dexamethasone in dentin facilitated crystallographic maturity, crystallinity and improved maturity and secondary structure of dentin collagen. CLINICAL SIGNIFICANCE Using dexamethasone-functionalized NPs before resin infiltration is a clear option to obtain dentin remineralization, as these NPs produce the reinforcement of the dentin structure, which will lead to the improvement of the longevity of resin restorations.
Collapse
Affiliation(s)
- Manuel Toledano
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Estrella Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - María T Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Fátima S Aguilera
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain.
| | - Raquel Toledano
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Enrique Fernández- Romero
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| | - Raquel Osorio
- Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, University of Granada, Granada 18071, Spain
| |
Collapse
|
6
|
Spencer P, Ye Q, Misra A, Chandler JR, Cobb CM, Tamerler C. Engineering peptide-polymer hybrids for targeted repair and protection of cervical lesions. FRONTIERS IN DENTAL MEDICINE 2022; 3. [PMID: 37153688 PMCID: PMC10162700 DOI: 10.3389/fdmed.2022.1007753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
By 2060, nearly 100 million people in the U.S. will be over age 65 years. One-third of these older adults will have root caries, and nearly 80% will have dental erosion. These conditions can cause pain and loss of tooth structure that interfere with eating, speaking, sleeping, and quality of life. Current treatments for root caries and dental erosion have produced unreliable results. For example, the glass-ionomer-cement or composite-resin restorations used to treat these lesions have annual failure rates of 44% and 17%, respectively. These limitations and the pressing need to treat these conditions in the aging population are driving a focus on microinvasive strategies, such as sealants and varnishes. Sealants can inhibit caries on coronal surfaces, but they are ineffective for root caries. For healthy, functionally independent elders, chlorhexidine varnish applied every 3 months inhibits root caries, but this bitter-tasting varnish stains the teeth. Fluoride gel inhibits root caries, but requires prescriptions and daily use, which may not be feasible for some older patients. Silver diamine fluoride can both arrest and inhibit root caries but stains the treated tooth surface black. The limitations of current approaches and high prevalence of root caries and dental erosion in the aging population create an urgent need for microinvasive therapies that can: (a) remineralize damaged dentin; (b) inhibit bacterial activity; and (c) provide durable protection for the root surface. Since cavitated and non-cavitated root lesions are difficult to distinguish, optimal approaches will treat both. This review will explore the multi-factorial elements that contribute to root surface lesions and discuss a multi-pronged strategy to both repair and protect root surfaces. The strategy integrates engineered peptides, novel polymer chemistry, multi-scale structure/property characterization and predictive modeling to develop a durable, microinvasive treatment for root surface lesions.
Collapse
|
7
|
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]
|
8
|
Reddy JK, Malini DL, Ballullaya SV, Pushpa S, Devalla S, Reddy AV. Influence of "MOTRCS" factors on the performance of various direct and indirect restorations: A finite element analysis. J Conserv Dent 2021; 24:15-23. [PMID: 34475674 PMCID: PMC8378485 DOI: 10.4103/jcd.jcd_471_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/25/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
Aim of the Study: The purpose of the study is to evaluate the occlusal relationship of the mesiobuccal cusp of a mandibular first molar with the marginal ridge of maxillary first molar and second premolar and to analyze the effect of the above occlusal relation on different direct and indirect restorations using finite element analysis (FEA). Methodology: Four hundred volunteers studying in a dental college were screened, of which 100 volunteers were selected for studying occlusal relationships based on the inclusion and exclusion criteria. The two most common occlusal relationships were considered for analyzing two direct (amalgam and direct composite restorations) and two indirect restorations (composite and ceramic restorations). Three-dimensional (3D) scanning of the models was performed, and Class II tooth preparations specific for each restorative material were prepared digitally on 3D models. FEA was employed to study von Mises (VM) stress, principal stresses, and cuspal deflection for each restorative material, and failure of the tooth-restoration unit was calculated using the modified Mohr failure criterion. Results: Among all the analyzed materials, cuspal deformation, principal stresses, and VM stresses were high for direct composite restoration and least for ceramic inlay. According to modified Mohr criteria, except for direct composite, all other materials performed better. Conclusion: Silver amalgam and ceramic restorations presented with minimal stress concentration and cuspal deflection, and Type I occlusal relationship presented with higher stress concentration compared to Type II.
Collapse
Affiliation(s)
- Jonnala Kruthika Reddy
- Department of Conservative Dentistry and Endodontics, St. Joseph Dental College, Eluru, Andhra Pradesh, India
| | - Duvvuri Lakshmi Malini
- Department of Conservative Dentistry and Endodontics, Government Dental College, Vijayawada, Andhra Pradesh, India
| | - Srinidhi Vishnu Ballullaya
- Department of Conservative Dentistry and Endodontics, St. Joseph Dental College, Eluru, Andhra Pradesh, India
| | - S Pushpa
- Department of Conservative Dentistry and Endodontics, St. Joseph Dental College, Eluru, Andhra Pradesh, India
| | - Srihari Devalla
- Department of Conservative Dentistry and Endodontics, St. Joseph Dental College, Eluru, Andhra Pradesh, India
| | - A Venkat Reddy
- Department of Prosthodontics and Crown and Bridge, St. Joseph Dental College, Eluru, Andhra Pradesh, India
| |
Collapse
|
9
|
Baldion PA, Cortes CC, Castellanos JE, Betancourt DE. Effect of myricetin on odontoblast-like cells and its potential to preserve resin-dentin Bonds. J Mech Behav Biomed Mater 2021; 117:104392. [PMID: 33601300 DOI: 10.1016/j.jmbbm.2021.104392] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/04/2021] [Accepted: 02/07/2021] [Indexed: 02/07/2023]
Abstract
Stabilization of the resin-dentin interface to increase the durability of adhesive dental restorations is a challenging task. The use of naturally occurring collagen crosslinking agents has been proposed to prevent degradation of the hybrid layer. Myricetin (MYR) is a flavonoid with a wide variety of beneficial effects and it has been used for the treatment of different systemic pathologies. The chemical structure of MYR makes it a powerful antioxidant, an inhibitor of matrix metalloproteinase (MMP) activity, and a collagen cross-linker. This study presents MYR as a novel treatment in operative dentistry to stabilize the resin-dentin interface by inhibiting MMPs and crosslinking the collagen. Viability tests carried out using a resazurin assay showed that MYR had no cytotoxic effects on human odontoblast-like cells and the phenotype was preserved. Fluorometric MMP activity assay and fluorescence microscopy revealed that the MMPs in the demineralized dentin were effectively inhibited by the application of MYR (600 μM for 120 s). A microtensile bond strength test was performed immediately and after six months of storage. The bond strength to dentin was not affected by MYR and was preserved over time. Demineralized dentin beams were evaluated to determine the dentin biomodification using microtensile strength and elastic modulus assays. MYR improved the biomechanical behavior of the demineralized dentin similarly to glutaraldehyde, a recognized crosslinking agent. These findings indicated that MYR acts as an MMP inhibitor, collagen cross-linker, and preserver of the bond strength. Furthermore, MYR is an ethanol-soluble molecule with a lower molecular weight than the other polyphenols; hence, it can be applied for a short time and diffuses deeply through the dentin without any associated cytotoxicity. This molecule has beneficial effects on the biological and mechanical behavior of the resin-dentin interface and may be used to effectively stabilize the hybrid layer in a clinical setting.
Collapse
Affiliation(s)
- Paula A Baldion
- Departamento de Salud Oral, Facultad de Odontologia, Universidad Nacional de Colombia, Colombia.
| | - Cristhian C Cortes
- Departamento de Salud Oral, Facultad de Odontologia, Universidad Nacional de Colombia, Colombia.
| | - Jaime E Castellanos
- Departamento de Medicina Oral y Ciencias Basicas, Facultad de Odontologia, Universidad Nacional de Colombia, Av. Cra 30 No. 45-03, Edificio 210, Bogotá, Colombia.
| | - Diego E Betancourt
- Departamento de Salud Oral, Facultad de Odontologia, Universidad Nacional de Colombia, Colombia.
| |
Collapse
|
10
|
Fracture toughening of peritubular microstructure in biological porous dentine. J Mech Behav Biomed Mater 2019; 93:194-203. [DOI: 10.1016/j.jmbbm.2019.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/01/2019] [Accepted: 02/03/2019] [Indexed: 11/22/2022]
|
11
|
Parthasarathy R, Misra A, Song L, Ye Q, Spencer P. Structure-property relationships for wet dentin adhesive polymers. Biointerphases 2018; 13:061004. [PMID: 30558430 PMCID: PMC6296910 DOI: 10.1116/1.5058072] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 12/23/2022] Open
Abstract
Dentin adhesive systems for composite tooth restorations are composed of hydrophilic/hydrophobic monomers, solvents, and photoinitiators. The adhesives undergo phase separation and concomitant compositional change during their application in the wet oral environment; phase separation compromises the quality of the hybrid layer in the adhesive/dentin interface. In this work, the adhesive composition in the hybrid layer can be represented using the phase boundaries of a ternary phase diagram for the hydrophobic monomer/hydrophilic monomer/water system. The polymer phases, previously unaccounted for, play an important role in determining the mechanical behavior of the bulk adhesive, and the chemomechanical properties of the phases are intimately related to the effects produced by differences in the hydrophobic-hydrophilic composition. As the composition of the polymer phases varies from hydrophobic-rich to hydrophilic-rich, the amount of the adsorbed water and the nature of polymer-water interaction vary nonlinearly and strongly correlate with the change in elastic moduli under wet conditions. The failure strain, loss modulus, and glass transition temperature vary nonmonotonically with composition and are explained based upon primary and secondary transitions observed in dynamic mechanical testing. Due to the variability in composition, the assignment of mechanical properties and the choice of suitable constitutive models for polymer phases in the hybrid layer are not straightforward. This work investigates the relationship between composition and chemomechanical properties of the polymer phases formed on the water-adhesive phase boundary using quasistatic and dynamic mechanical testing, mass transfer experiments, and vibrational spectroscopy.
Collapse
Affiliation(s)
- Ranganathan Parthasarathy
- Department of Civil and Architectural Engineering, Tennessee State University, 3500 John A Merritt Blvd, Nashville, Tennessee 37209
| | - Anil Misra
- Department of Civil and Environmental Engineering, Institute for Bioengineering Research, University of Kansas, 5104B Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Linyong Song
- Institute for Bioengineering Research, University of Kansas, 5104A Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Qiang Ye
- Institute for Bioengineering Research, University of Kansas, 5101E Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Paulette Spencer
- Department of Mechanical Engineering, Institute for Bioengineering Research, University of Kansas, 3111 Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
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.
Collapse
Affiliation(s)
- M Toledano
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071 - Granada - Spain,
| | | | | | | | | | | |
Collapse
|
14
|
Toledano M, Toledano-Osorio M, Guerado E, Caso E, Osorio E, Osorio R. Assessing bone quality through mechanical properties in postmenopausal trabecular bone. Injury 2018; 49 Suppl 2:S3-S10. [PMID: 30219145 DOI: 10.1016/j.injury.2018.07.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND The inner structure of trabecular bone is a result of structural optimization provided by remodeling processes. Changes in hormonal status related to menopause cause bone tissue loss and micro-architectural deterioration with a consequent susceptibility to fracture. Accumulation of micro-damage in bone, as a function of the rate of production and rate of repair, underlies the development of stress fractures, increasing fragility associated to age and osteoporosis, especially in transmenopausal women. PATIENTS AND METHODS Quasi-static and nano-dynamic mechanical characterization were undertaken in trabecular bone from femoral neck biopsies of postmenopausal women. AFM (Atomic Force Microscopy) complementary studies were performed to determine nano-roughness (SRa) and the fibrils width of collagen. Nanoindentations were used to quantify transmenopausal changes in intrinsic mechanical properties of trabecular bone: hardness (Hi), modulus of Young (Ei), complex modulus (E*), tan delta (δ), storage modulus (E') and loss modulus (E"). RESULTS As result of the quasi-static measurements, 0.149 (0.036) GPa and 2.95 (0.73) GPa of Hi and Ei were obtained, respectively. As result of the nano-dynamic measurements, 17.94 (3.15), 0.62 (0.10), 13.79 (3.21 and 6.39 (1.28) GPa of E*, tan (δ), E' and E" were achieved, respectively. 101.07 SRa and 831.28 nm of fibrils width were additionally obtained. CONCLUSIONS This study poses a first approach to the measurement of bone quality in postmenopausal trabecular bone by combining quasi-static, nano-DMA analysis and tribology of dentin surface through AFM characterization.
Collapse
Affiliation(s)
- Manuel Toledano
- 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
| | - Enrique Guerado
- Department of Orthopaedic Surgery and Traumatology, Hospital Universitario Costa del Sol, University of Malaga, Autovía A-7, Km 187, 29603, Marbella, Malaga, Spain
| | - Enrique Caso
- Research Unit, Hospital Universitario Costa del Sol, University of Malaga, Autovía A-7, Km 187, 29603, Marbella. Malaga, Spain
| | - Estrella Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja 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
| |
Collapse
|
15
|
Chan T, Küçükkaya Eren S, Wong R, Parashos P. In vitro fracture strength and patterns in root-filled teeth restored with different base materials. Aust Dent J 2017; 63:99-108. [PMID: 28941281 DOI: 10.1111/adj.12570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND There is little research on the effects of an intermediate base on the fracture strength of root-filled teeth. This study compared the fracture strengths and patterns of root-filled teeth restored with intermediate bases of glass-ionomer cement (GIC), zinc polycarboxylate cement (ZPC), dual-cured resin composite (DCRC) and Biodentine® under resin composite. METHODS Standardized cavities were prepared in 100 extracted human maxillary and mandibular premolars, and root canal treatment was performed. The teeth were stratified and randomly allocated to five groups (n = 20): (i) GIC; (ii) ZPC; (iii) DCRC; (iv) Biodentine; and (v) prepared but unrestored (control). The teeth were subjected to an oblique, ramped load until fracture. The fracture loads, level, mode and location were recorded. RESULTS Mean fracture strengths of all restored groups were not significantly different amongst the groups. There were significant overall effects on mean fracture strength for tooth type (P = 0.002) and buccolingual width of the crown (P = 0.001). CONCLUSIONS The four materials were appropriate intermediate bases. The laminate restorative technique promoted fracture strengths that are likely to withstand normal and maximum masticatory function. The base material can influence failure mode, which may have implications for the clinical presentation of fractures of root-filled teeth.
Collapse
Affiliation(s)
- T Chan
- The Melbourne Dental School, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Victoria, Australia
| | - S Küçükkaya Eren
- Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey
| | - R Wong
- The Melbourne Dental School, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Victoria, Australia
| | - P Parashos
- The Melbourne Dental School, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Victoria, Australia
| |
Collapse
|
16
|
Toledano M, Osorio R, Guerado E, Caso E, Osorio E. Nanostructure in the trabecular bone of postmenopausal women: Mechanical and chemical analysis. Injury 2017; 48 Suppl 6:S26-S33. [PMID: 29162238 DOI: 10.1016/s0020-1383(17)30791-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The possibility of diagnosis and prediction of multiple disorders in trabecular bone through nano-biomechanics and chemical analysis are summarized. Improvements to the understating of the compositional contributors of bone mineral and organic components to mechanical competence are crucial. Viscoelastic properties and Raman characterization have been used to evaluate possible alterations of the trabecular bone associated with aging, disease, or injury. In this study, the trabecular bone of postmenopausal women has been analyzed throughout. (a) Nanomechanical characterization, by using nano-DMA: complex modulus, tan δ, loss modulus (E'), and storage modulus (E'); and (b) Raman analysis: relative presence of minerals, carbonate-to-phosphate ratio (both from the mineral components), the crosslinking and nature/secondary structure of collagen (both from the organic components). Complementary nano-morphological studies were done assessing roughness (SRa) and collagen fibrils width, on this trabecular bone. A general idea of the behavior of the viscoelastic performance can be obtained by the Tan δ (E″/E'), that achieved 0.98GPa of damping. 249nm and 0.898μm of SRa roughness and fibrils width were obtained, respectively. The relative presence of minerals, the carbonate-to-phosphate ratio, the crosslinking and the nature/secondary structure of collagen, between 700 and 1700cm-1, were also obtained, in order to propose a study protocol for trabecular bone characterization.
Collapse
Affiliation(s)
- Manuel Toledano
- Faculty of Dentistry, Dental Materials Section, University of Granada, Granada, Spain
| | - Raquel Osorio
- Faculty of Dentistry, Dental Materials Section, University of Granada, Granada, Spain.
| | - Enrique Guerado
- Department of Orthopaedic Surgery and Traumatology, Hospital Universitario Costa del Sol, University of Malaga, Malaga, Spain
| | - Enrique Caso
- Research Unit, Hospital Universitario Costa del Sol, University of Malaga, Malaga, Spain
| | - Estrella Osorio
- Faculty of Dentistry, Dental Materials Section, University of Granada, Granada, Spain
| |
Collapse
|
17
|
The peritubular reinforcement effect of porous dentine microstructure. PLoS One 2017; 12:e0183982. [PMID: 28859165 PMCID: PMC5578600 DOI: 10.1371/journal.pone.0183982] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/15/2017] [Indexed: 12/02/2022] Open
Abstract
In the current study, we evaluate the equivalent stiffness of peritubular reinforcement effect (PRE) of porous dentine optimized by the thickness of peritubular dentine (PTD). Few studies to date have evaluated or quantitated the effect of PRE on composite dentine. The miscrostructure of porous dentine is captured by scanning electron microscope images, and then finite element modeling is used to quantitate the deformation and stiffness of the porous dentine structure. By optimizing the radius of PTD and dentine tubule (DT), the proposed FE model is able to demonstrate the effect of peritubular reinforcement on porous dentine stiffness. It is concluded that the dentinal equivalent stiffness is reduced and degraded with the increase of the radius of DT (i.e., porosity) in the certain ratio value of Ep/Ei and certain radius of PTD, where Ep is the PTD modulus and Ei is the intertubular dentine modulus. So in order to ensure the whole dentinal equivalent stiffness is not loss, the porosity should get some value while the Ep/Ei is certain. Thus, PTD prevents the stress concentration around DTs and reduces the risk of DTs failure. Mechanically, the overall role of PTD appears to enhance the stiffness of the dentine composite structure. These results provide some new and significant insights into the biological evolution of the optimal design for the porous dentine microstructure. These findings on the biological microstructure design of dentine materials are applicable to other engineering structural designs aimed at increasing the overall structural strength.
Collapse
|
18
|
Toledano M, Osorio R, Osorio E, Cabello I, Toledano-Osorio M, Aguilera FS. A zinc chloride-doped adhesive facilitates sealing at the dentin interface: A confocal laser microscopy study. J Mech Behav Biomed Mater 2017; 74:35-42. [PMID: 28535395 DOI: 10.1016/j.jmbbm.2017.04.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 03/06/2017] [Accepted: 04/17/2017] [Indexed: 10/19/2022]
Abstract
The aim of this study was to ascertain the effect of Zn-doping of dental adhesives and mechanical load cycling on the micromorphology of the resin-dentin interdiffusion zone (of sound and caries affected dentin). The investigation considered two different Zn-doped adhesive approaches and evaluated the interface using a doubled dye fluorescent technique and a calcium chelator fluorophore under a confocal laser scanning microscopy. Sound and carious dentin-resin interfaces of unloaded specimens were deficiently resin-hybridized, in general. These samples showed a rhodamine B-labeled hybrid layer and adhesive layer completely affected by fluorescein penetration (nanoleakage) through the porous resin-dentin interface. It was thicker after phosphoric acid-etching and more extended in carious dentin. Zn-doping promoted an improved sealing of the resin-dentin interface, a decrease of the hybrid layer porosity, and an increment of dentin mineralization. Load cycling augmented the sealing of the Zn-doped resin-dentin interfaces, as porosity and nanoleakage diminished, and even disappeared in caries-affected dentin substrata conditioned with EDTA. Sound and carious dentin specimens analyzed with the xylenol orange technique produced a clearly outlined fluorescence when resins were Zn-doped, due to a consistent Ca-mineral deposition within the bonding interface and inside the dentinal tubules. It was more evident when load cycling was applied on specimens treated with self-etching adhesives that were Zn-doped. Micropermeability at the resin-dentin interface diminished after combining EDTA pretreatment, ZnCl2-doping and mechanical loading stimuli on restorations. It is clearly preferable to include the zinc compounds into the bonding constituents of the self-etching adhesives, instead of into the primer ingredients. The promoted new mineral segments contributed to reduce or avoid both porosity and nanoleakage from the load cycled Zn-doped resin dentin interfaces. EDTA+SB-ZnCl2 or SEB·Bd-Zn doping are preferred to treat caries-affected dentin surfaces. ZnO-doping encouraged for etch-and-rinse adhesives.
Collapse
Affiliation(s)
- Manuel Toledano
- University of Granada, Faculty of Dentistry, Dental Materials Section Colegio Máximo de Cartuja 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
| | - Estrella Osorio
- University of Granada, Faculty of Dentistry, Dental Materials Section Colegio Máximo de Cartuja s/n, 18071 Granada, Spain
| | - Inmaculada Cabello
- 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
| | - Fátima S Aguilera
- University of Granada, Faculty of Dentistry, Dental Materials Section Colegio Máximo de Cartuja s/n, 18071 Granada, Spain
| |
Collapse
|
19
|
Song L, Ye Q, Ge X, Misra A, Tamerler C, Spencer P. Probing the neutralization behavior of zwitterionic monomer-containing dental adhesive. Dent Mater 2017; 33:564-574. [PMID: 28366234 PMCID: PMC5480395 DOI: 10.1016/j.dental.2017.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/28/2017] [Accepted: 03/14/2017] [Indexed: 01/29/2023]
Abstract
OBJECTIVE To investigate the polymerization kinetics, neutralization behavior, and mechanical properties of amine-functionalized dental adhesive cured in the presence of zwitterionic monomer, methacryloyloxyethyl phosphorylcholine (MPC). METHODS The control adhesive was a mixture based on HEMA/BisGMA/2-N-morpholinoethyl methacrylate (MEMA) (40/30/30, w/w/w). The control and experimental formulations containing MPC were characterized with regard to water miscibility of liquid resins, photopolymerization kinetics, water sorption and solubility, dynamic mechanical properties and leachables from the polymers (aged in ethanol). The neutralization behavior of the adhesives was determined by monitoring the pH of lactic acid (LA) solution. RESULTS The water miscibility decreased with increasing MPC amount. The water sorption of experimental copolymer specimen was greater than the control. The addition of 8wt% water led to improved photo-polymerization efficiency for experimental formulations at MPC of 2.5 and 5wt%, and significant reduction in the cumulative amounts of leached HEMA, BisGMA, and MEMA, i.e. 90, 60 and 50% reduction, respectively. The neutralization rate of MPC-containing adhesive was faster than control. The optimal MPC concentration in the formulations was 5wt%. SIGNIFICANCE Incompatibility between MEMA and MPC led to a decrease in water miscibility of the liquid resins. Water (at 8wt%) in the MPC-containing formulations (2.5-5wt% MPC) led to higher DC, faster RPmax and significant reduction in leached HEMA, BisGMA, and MEMA. The neutralization rate was enhanced with the addition of MPC in the amine-containing formulation. Promoting the neutralization capability of dentin adhesives could play an important role in reducing recurrent decay at the composite/tooth interface.
Collapse
Affiliation(s)
- Linyong Song
- University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Qiang Ye
- University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA.
| | - Xueping Ge
- University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Anil Misra
- University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA; University of Kansas, Department of Civil Engineering, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Candan Tamerler
- University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA; University of Kansas, Department of Mechanical Engineering, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Paulette Spencer
- University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA; University of Kansas, Department of Mechanical Engineering, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA.
| |
Collapse
|
20
|
Ye Q, Spencer P, Yuca E, Tamerler C. Engineered Peptide Repairs Defective Adhesive-Dentin Interface. MACROMOLECULAR MATERIALS AND ENGINEERING 2017; 302:1600487. [PMID: 29056869 PMCID: PMC5650097 DOI: 10.1002/mame.201600487] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Failure of dental composite restorations is primarily due to recurrent decay at the tooth-composite interface. At this interface, the adhesive and its bond with dentin is the barrier between the restored tooth and the oral environment. In vivo degradation of the bond formed at the adhesive/dentin (a/d) interface follows a cascade of events leading to weakening of the composite restoration. Here, a peptide-based approach is developed to mineralize deficient dentin matrices at the a/d interface. Peptides that have an inherent capacity to self-assemble on dentin and to induce calcium-phosphate remineralization are anchored at the interface. Distribution of adhesive, collagen, and mineral is analyzed using micro-Raman spectroscopy and fluorescence microscopy. The analysis demonstrates remineralization of the deficient dentin matrices achieved throughout the interface with homogeneous distribution of mineral. The peptide-based remineralization demonstrated here can be an enabling technology to design integrated biomaterial-tissue interfaces.
Collapse
Affiliation(s)
- Qiang Ye
- Bioengineering Research Center (BERC), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS 66045, USA
| | - Paulette Spencer
- Bioengineering Research Center (BERC), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS 66045, USA. Department of Mechanical Engineering, University of Kansas (KU), 1530 W. 15th St, Lawrence, KS 66045, USA
| | - Esra Yuca
- Bioengineering Research Center (BERC), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS 66045, USA
| | - Candan Tamerler
- Bioengineering Research Center (BERC), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS 66045, USA. Department of Mechanical Engineering, University of Kansas (KU), 1530 W. 15th St, Lawrence, KS 66045, USA
| |
Collapse
|
21
|
Mechanical loading influences the viscoelastic performance of the resin-carious dentin complex. Biointerphases 2017; 12:021001. [PMID: 28376622 DOI: 10.1116/1.4979633] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to evaluate the changes in the mechanical behavior and bonding capability of Zn-doped resin-infiltrated caries-affected dentin interfaces. Dentin surfaces were treated with 37% phosphoric acid (PA) followed by application of a dentin adhesive, single bond (SB) (PA+SB) or by 0.5 M ethylenediaminetetraacetic acid (EDTA) followed by SB (EDTA+SB). ZnO microparticles of 10 wt. % or 2 wt. % ZnCl2 was added into SB, resulting in the following groups: PA+SB, PA+SB-ZnO, PA+SB-ZnCl2, EDTA+SB, EDTA+SB-ZnO, EDTA+SB-ZnCl2. Bonded interfaces were stored for 24 h, and tested or submitted to mechanical loading. Microtensile bond strength was assessed. Debonded surfaces were evaluated by scanning electron microscopy and elemental analysis. The hybrid layer, bottom of the hybrid layer, and peritubular and intertubular dentin were evaluated using a nanoindenter. The load/displacement responses were used for the nanodynamic mechanical analysis III to estimate complex modulus, tan delta, loss modulus, and storage modulus. The modulus mapping was obtained by imposing a quasistatic force setpoint to which a sinusoidal force was superimposed. Atomic force microscopy imaging was performed. Load cycling decreased the tan delta at the PA+SB-ZnCl2 and EDTA+SB-ZnO interfaces. Tan delta was also diminished at peritubular dentin when PA+SB-ZnO was used, hindering the dissipation of energy throughout these structures. Tan delta increased at the interface after using EDTA+SB-ZnCl2, lowering the energy for recoil or failure. After load cycling, loss moduli at the interface decreased when using ZnCl2 as doping agent, increasing the risk of fracture; but when using ZnO, loss moduli was dissimilarly affected if dentin was EDTA-treated. The border between intertubular and peritubular dentin attained the highest discrepancy in values of viscoelastic properties, meaning a risk for cracking and breakdown of the resin-dentin interface. PA used on dentin provoked differences in complex and storage modulus values at the intertubular and peritubular structures, and these differences were higher than when EDTA was employed. In these cases, the long-term performance of the restorative interface will be impaired.
Collapse
|
22
|
Ions-modified nanoparticles affect functional remineralization and energy dissipation through the resin-dentin interface. J Mech Behav Biomed Mater 2017; 68:62-79. [DOI: 10.1016/j.jmbbm.2017.01.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 01/22/2023]
|
23
|
Toledano M, Osorio R, Osorio E, García-Godoy F, Toledano-Osorio M, Aguilera FS. Advanced zinc-doped adhesives for high performance at the resin-carious dentin interface. J Mech Behav Biomed Mater 2016; 62:247-267. [DOI: 10.1016/j.jmbbm.2016.05.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/04/2016] [Accepted: 05/09/2016] [Indexed: 01/22/2023]
|
24
|
Nanoscopic dynamic mechanical analysis of resin-infiltrated dentine, under in vitro chewing and bruxism events. J Mech Behav Biomed Mater 2015; 54:33-47. [PMID: 26414515 DOI: 10.1016/j.jmbbm.2015.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/01/2015] [Accepted: 09/04/2015] [Indexed: 11/23/2022]
Abstract
The aim of this study was to evaluate the induced changes in mechanical behavior and bonding capability of resin-infiltrated dentine interfaces, after application of mechanical stimuli. Dentine surfaces were subjected to partial demineralization through 37% phosphoric acid etching followed by the application of an etch-and-rinse dentine adhesive, Single Bond (3M/ESPE). Bonded interfaces were stored in simulated body fluid during 24h, and then tested or submitted to the mechanical loading challenge. Different loading waveforms were applied: No cycling (I), 24h cycled in sine (II) or square (III) waves, sustained loading held for 24h (IV) or sustained loading held for 72h (V). Microtensile bond strength (MTBS) was assessed for the different groups. Debonded dentine surfaces were studied by field emission scanning electron microscopy (FESEM). At the resin-dentine interface, both the hybrid layer (HL) and the bottom of the hybrid layer (BHL), and both peritubular and intertubular 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 and storage modulus. Dye assisted Confocal Microscopy Evaluation was used to assess sealing ability. Load cycling increased the percentage of adhesive failures in all groups. Specimens load cycled in held 24h attained the highest complex and storage moduli at HL and BHL. The storage modulus was maximum in specimens load cycled in held 24h at peritubular dentine, and the lowest values were attained at intertubular dentine. The storage modulus increased in all mechanical tests, at peritubular dentine. An absence of micropermeability and nanoleakage after loading in sine and square waveforms were encountered. Porosity of the resin-dentine interface was observed when specimens were load cycled in held 72h. Areas of combined sealing and permeability were discovered at the interface of specimens load cycled in held 24h. Crack-bridging images appeared in samples load cycled with sine waveform, after FESEM examination.
Collapse
|
25
|
Anchieta RB, Machado LS, Martini AP, Santos PHD, Giannini M, Janal M, Tovar N, Sundfeld RH, Rocha EP, Coelho PG. Effect of long-term storage on nanomechanical and morphological properties of dentin-adhesive interfaces. Dent Mater 2014; 31:141-53. [PMID: 25529501 DOI: 10.1016/j.dental.2014.11.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 08/23/2014] [Accepted: 11/14/2014] [Indexed: 11/25/2022]
Abstract
INTRODUCTION To evaluate the influence of storage time on the elastic modulus, micromorphology, nanoleakage, and micromechanical behavior of the dentin-adhesive interfaces of five adhesive systems (Scotchbond Multi-Purpose, Clearfil SE Bond, One Up Bond F, Adper Easy One, and Filtek LS Adhesive) after 24h (T0) and 12 months (T1). METHODS Fifty teeth were restored and distributed according to each adhesive system (n=10). At least four specimens were obtained from each tooth. One specimen was evaluated under SEM to obtain the micromorphology of dentin-adhesive interface (DAI). Two specimens were used to assess nanoleakage, one tested in T0 and the other in T1. The last specimen was used for nanoindentation, in T0 and T1, to obtain the initial and final mechanical properties of DAI structures. Two non-restored teeth were evaluated under SEM to obtain the dentin morphology. Laboratorial data were used to build 15 finite element models to assess the maximum principal stress in each time of analysis. RESULTS Storage resulted in hydrolysis of the dentin-adhesive interfaces for all groups. Silver impregnation increased for all groups after 1 year storage (p<.05), except for Clearfil SE Bond. In general, a decrease in elastic modulus values was observed for all groups from T0 to T1 (p<.05), mainly at the hybrid layer. The FEAs showed higher stress levels at T1 than T0 simulations for all adhesives. CONCLUSION At T1, degradation occurred at the dentin-adhesive interface formed by all adhesives, and the intensity of degradation differed depending on the type of adhesive system used. The interface formed by the self-etching primer containing the 10-MDP functional monomer showed the highest stability among the adhesive systems after 12 months of storage.
Collapse
Affiliation(s)
- Rodolfo Bruniera Anchieta
- Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil; New York University, Department of Biomaterial and Biomimetics, New York, NY, USA.
| | - Lucas Silveira Machado
- Univ. Estadual Paulista -UNESP Araçatuba Dental School, Department of Restorative Dentistry, Araçatuba, SP, Brazil; New York University, Department of Biomaterial and Biomimetics, New York, NY, USA
| | - Ana Paula Martini
- Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil
| | - Paulo Henrique dos Santos
- Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil; Univ. Estadual Paulista -UNESP Araçatuba Dental School, Department of Restorative Dentistry, Araçatuba, SP, Brazil
| | - Marcelo Giannini
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| | - Malvin Janal
- New York University, Department of Biomaterial and Biomimetics, New York, NY, USA
| | - Nick Tovar
- New York University, Department of Biomaterial and Biomimetics, New York, NY, USA
| | - Renato Herman Sundfeld
- Univ. Estadual Paulista -UNESP Araçatuba Dental School, Department of Restorative Dentistry, Araçatuba, SP, Brazil
| | - Eduardo Passos Rocha
- Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil
| | - Paulo G Coelho
- New York University, Department of Biomaterial and Biomimetics, New York, NY, USA
| |
Collapse
|
26
|
Singh V, Misra A, Parthasarathy R, Ye Q, Spencer P. Viscoelastic properties of collagen-adhesive composites under water-saturated and dry conditions. J Biomed Mater Res A 2014; 103:646-57. [PMID: 24753362 DOI: 10.1002/jbm.a.35204] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 03/05/2014] [Accepted: 04/18/2014] [Indexed: 11/06/2022]
Abstract
To investigate the time- and rate-dependent mechanical properties of collagen-adhesive composites, creep and monotonic experiments are performed under dry and wet conditions. The composites are prepared by infiltration of dentin adhesive into a demineralized bovine dentin. Experimental results show that for small stress level under dry conditions, both the composite and the neat adhesive have similar behavior. On the other hand, in wet conditions, the composites are significantly soft and weak compared to the neat adhesives. The behavior in the wet condition is found to be affected by the hydrophilicity of both the adhesive and the collagen. As the adhesive-collagen composites are a part of the complex construct that forms the adhesive-dentin interface, their presence will affect the overall performance of the restoration. We find that Kelvin-Voigt model with at least four elements is required to fit the creep compliance data, indicating that the adhesive-collagen composites are complex polymers with several characteristic time scales whose mechanical behavior will be significantly affected by loading rates and frequencies. Such mechanical properties have not been investigated widely for these types of materials. The derived model provides an additional advantage that it can be exploited to extract other viscoelastic properties which are, generally, time consuming to obtain experimentally. The calibrated model is utilized to obtain stress relaxation function, frequency-dependent storage and loss modulus, and rate-dependent elastic modulus.
Collapse
Affiliation(s)
- Viraj Singh
- Department of Mechanical Engineering, University of Kansas, Lawrence, Kansas, 66045-7609; Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045-7609
| | | | | | | | | |
Collapse
|
27
|
Misra A, Parthasarathy R, Ye Q, Singh V, Spencer P. Swelling equilibrium of dentin adhesive polymers formed on the water-adhesive phase boundary: experiments and micromechanical model. Acta Biomater 2014; 10:330-42. [PMID: 24076070 PMCID: PMC3843361 DOI: 10.1016/j.actbio.2013.09.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/29/2013] [Accepted: 09/17/2013] [Indexed: 11/21/2022]
Abstract
During their application to the wet, oral environment, dentin adhesives can experience phase separation and composition change, which can compromise the quality of the hybrid layer formed at the dentin-adhesive interface. The chemical composition of polymer phases formed in the hybrid layer can be represented using a ternary water-adhesive phase diagram. In this paper, these polymer phases are characterized using a suite of mechanical tests and swelling experiments. The experimental results were evaluated using a granular micromechanics-based model incorporating poro-mechanical effects and polymer-solvent thermodynamics. The variation in the model parameters and model-predicted polymer properties was studied as a function of composition along the phase boundary. The resulting structure-property correlations provide insight into interactions occurring at the molecular level in the saturated polymer system. These correlations can be used for modeling the mechanical behavior of the hybrid layer, and are expected to aid in the design and improvement of water-compatible dentin adhesive polymers.
Collapse
Affiliation(s)
- A Misra
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA; Civil, Environmental and Architectural Engineering Department, Learned Hall, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA; Department of Mechanical Engineering, University of Kansas, Lawrence, KS, USA.
| | | | | | | | | |
Collapse
|
28
|
Singh V, Misra A, Parthasarathy R, Ye Q, Park J, Spencer P. Mechanical properties of methacrylate-based model dentin adhesives: effect of loading rate and moisture exposure. J Biomed Mater Res B Appl Biomater 2013; 101:1437-43. [PMID: 23744598 DOI: 10.1002/jbm.b.32963] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/07/2013] [Accepted: 04/10/2013] [Indexed: 11/10/2022]
Abstract
The aim of this study is to investigate the mechanical behavior of model methacrylate-based dentin adhesives under conditions that simulate the wet oral environment. A series of monotonic and creep experiments were performed on rectangular beam samples of dentin adhesive in three-point bending configuration under different moisture conditions. The monotonic test results show a significant effect of loading rate on the failure strength and the linear limit (yield point) of the stress-strain response. In addition, these tests show that the failure strength is low, and the failure occurs at a smaller deformation when the test is performed under continuously changing moisture conditions. The creep test results show that under constant moisture conditions, the model dentin adhesives can have a viscoelastic response under certain low loading levels. However, when the moisture conditions vary under the same low loading levels, the dentin adhesives have an anomalous creep response accompanied by large secondary creep and high strain accumulation.
Collapse
Affiliation(s)
- Viraj Singh
- Mechanical Engineering Department, University of Kansas, Lawrence, Kansas, 66045-7609; Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045-7609
| | | | | | | | | | | |
Collapse
|
29
|
Bohaty BS, Ye Q, Misra A, Sene F, Spencer P. Posterior composite restoration update: focus on factors influencing form and function. Clin Cosmet Investig Dent 2013; 5:33-42. [PMID: 23750102 PMCID: PMC3666491 DOI: 10.2147/ccide.s42044] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 12/01/2022] Open
Abstract
Restoring posterior teeth with resin-based composite materials continues to gain popularity among
clinicians, and the demand for such aesthetic restorations is increasing. Indeed, the most common
aesthetic alternative to dental amalgam is resin composite. Moderate to large posterior composite
restorations, however, have higher failure rates, more recurrent caries, and increased frequency of
replacement. Investigators across the globe are researching new materials and techniques that will
improve the clinical performance, handling characteristics, and mechanical and physical properties
of composite resin restorative materials. Despite such attention, large to moderate posterior
composite restorations continue to have a clinical lifetime that is approximately one-half that of
the dental amalgam. While there are numerous recommendations regarding preparation design,
restoration placement, and polymerization technique, current research indicates that restoration
longevity depends on several variables that may be difficult for the dentist to control. These
variables include the patient’s caries risk, tooth position, patient habits, number of
restored surfaces, the quality of the tooth–restoration bond, and the ability of the
restorative material to produce a sealed tooth–restoration interface. Although clinicians
tend to focus on tooth form when evaluating the success and failure of posterior composite
restorations, the emphasis must remain on advancing our understanding of the clinical variables that
impact the formation of a durable seal at the restoration–tooth interface. This paper
presents an update of existing technology and underscores the mechanisms that negatively impact the
durability of posterior composite restorations in permanent teeth.
Collapse
Affiliation(s)
- Brenda S Bohaty
- Department of Pediatric Dentistry, University of Missouri-Kansas City School of Dentistry, Kansas City, MO, USA; ; Department of Pediatric Dentistry, Children's Mercy Hospital, Kansas City, MO, USA
| | | | | | | | | |
Collapse
|
30
|
Papadogiannis D, Lakes RS, Papadogiannis Y, Tolidis K. Mechanical viscoelastic behavior of dental adhesives. Dent Mater 2013; 29:693-701. [PMID: 23601583 DOI: 10.1016/j.dental.2013.03.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 10/29/2012] [Accepted: 03/18/2013] [Indexed: 10/27/2022]
Abstract
OBJECTIVES The purpose of the study was to evaluate the mechanical properties of dental adhesive materials at different testing temperatures after dry and wet storage. METHODS Specimens (d=1 mm, l=18 mm) from six materials were tested: Silorane Adhesive System (SL), Heliobond (HE), One-Step Plus (OS), Optibond Solo Plus (OP), cmf Adhesive System (CF) and Protobond (PR). Static and creep testing was performed by applying a constant torque below the proportional limit of the materials, while dynamic testing consisted of dynamic torsional loading. Experiments were performed after 24h of dry and wet storage under temperatures from 21°C to 50°C and various viscoelastic parameters were calculated. RESULTS Shear modulus ranged from 0.19 to 1.99 GPa, while flexural modulus from 0.67 to 5.69 GPa. Most of the materials were affected by the presence of water and increase of temperature. OP showed the highest recovery after creep, while SL exhibited the highest permanent deformation. SIGNIFICANCE Contact with water after polymerization and increase of temperature resulted in a decline of the mechanical properties, especially for the HEMA-containing adhesives.
Collapse
Affiliation(s)
- D Papadogiannis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
| | | | | | | |
Collapse
|
31
|
Mutluay MM, Zhang K, Ryou H, Yahyazadehfar M, Majd H, Xu HHK, Arola D. On the fatigue behavior of resin-dentin bonds after degradation by biofilm. J Mech Behav Biomed Mater 2012; 18:219-31. [PMID: 23276517 DOI: 10.1016/j.jmbbm.2012.10.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 10/25/2012] [Accepted: 10/26/2012] [Indexed: 02/09/2023]
Abstract
The durability of resin-dentin bonds is a growing concern in the placement of composite restorations. Most reported evaluations concerning the mechanical behavior of the bonded interface are conducted using static loading to failure only. They also do not account for the acid production of biofilms, which is one of the most common contributors to interfacial failures in vivo. In this investigation resin-dentin bonded interface specimens were exposed to S. mutans for 14 days and then subjected to quasi-static or cyclic four-point flexure to failure. Control specimens (without biofilm) were evaluated after aging for one and fourteen days. While no significant difference in flexure strength resulted from the duration of water aging (66.2 MPa vs. 56.9 MPa), biofilm exposure caused a significant reduction in strength (29.3 MPa; p ≤ 0.000). After water aging for one and fourteen days the apparent endurance limits were 13.0 MPa and 13.1 MPa, respectively. Biofilm treatment caused a significant (p ≤ 0.001) reduction in fatigue resistance of the interface, and the endurance limit was reduced to 9.9 MPa. Fatigue failure of the control specimens initiated within the resin composite adjacent to the interface, whereas failure of the biofilm treated specimens initiated within the hybrid layer and appeared attributed to the localized demineralization of dentin. Biofilm degradation is an important consideration in assessing the durability of resin-dentin bonds.
Collapse
Affiliation(s)
- Mustafa Murat Mutluay
- Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland
| | | | | | | | | | | | | |
Collapse
|
32
|
Carvalho RM, Tjäderhane L, Manso AP, Carrilho MR, Carvalho CAR. Dentin as a bonding substrate. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1601-1546.2012.00274.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
33
|
Parthasarathy R, Misra A, Park J, Ye Q, Spencer P. Diffusion coefficients of water and leachables in methacrylate-based crosslinked polymers using absorption experiments. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2012; 23:1157-1172. [PMID: 22430592 PMCID: PMC3361067 DOI: 10.1007/s10856-012-4595-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 02/16/2012] [Indexed: 05/30/2023]
Abstract
The diffusion of water into dentin adhesive polymers and leaching of unpolymerized monomer from the adhesive are linked to their mechanical softening and hydrolytic degradation. Therefore, diffusion coefficient data are critical for the mechanical design of these polymeric adhesives. In this study, diffusion coefficients of water and leachables were obtained for sixteen methacrylate-based crosslinked polymers using absorption experiments. The experimental mass change data was interpreted using numerical solution of the two-dimensional diffusion equations. The calculated diffusion coefficients varied from 1.05 × 10(-8) cm(2)/sec (co-monomer TMTMA) to 3.15 × 10(-8) cm(2)/sec (co-monomer T4EGDMA). Correlation of the diffusion coefficients with crosslink density and hydrophilicity showed an inverse trend (R(2) = 0.41). The correlation of diffusion coefficient with crosslink density and hydrophilicity are closer for molecules differing by simple repeat units (R(2) = 0.95). These differences in the trends reveal mechanisms of interaction of the diffusing water with the polymer structure.
Collapse
Affiliation(s)
- Ranganathan Parthasarathy
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
- Bioengineering Graduate Program, University of Kansas, Lawrence, KS, USA
| | - Anil Misra
- Civil, Environmental and Architectural Engineering Department
- Bioengineering Graduate Program, University of Kansas, Lawrence, KS, USA
| | - Jonggu Park
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
| | - Qiang Ye
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
| | - Paulette Spencer
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS, USA
| |
Collapse
|
34
|
Raposo LH, Armstrong SR, Maia RR, Qian F, Geraldeli S, Soares CJ. Effect of specimen gripping device, geometry and fixation method on microtensile bond strength, failure mode and stress distribution: Laboratory and finite element analyses. Dent Mater 2012; 28:e50-62. [DOI: 10.1016/j.dental.2012.02.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 11/29/2011] [Accepted: 02/20/2012] [Indexed: 10/28/2022]
|
35
|
Spencer P, Jonggu Park QY, Misra A, Bohaty BS, Singh V, Parthasarathy R, Sene F, de Paiva Gonçalves SE, Laurence J. Durable bonds at the adhesive/dentin interface: an impossible mission or simply a moving target? BRAZILIAN DENTAL SCIENCE 2012; 15:4-18. [PMID: 24855586 PMCID: PMC4028112 DOI: 10.14295/bds.2012.v15i1.790] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2023] Open
Abstract
Composite restorations have higher failure rates, more recurrent caries and increased frequency of replacement as compared to dental amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and failure. The gingival margin of composite restora tions is particularly vulnerable to decay and at this margin, the adhesive and its seal to dentin provides the primary barrier between the prepared tooth and the environment. The intent of this article is to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface.
Collapse
Affiliation(s)
- Paulette Spencer
- Department of Mechanical Engineering - Bioengineering Research Center - University of Kansas - Lawrence - KS
| | | | - Anil Misra
- Bioengineering Research Center - Department of Civil Engineering - University of Kansas - Lawrence - KS
| | - Brenda S Bohaty
- Department of Pediatric Dentistry - University of Missouri - Kansas City - School of Dentistry - Kansas City - MO
| | - Viraj Singh
- Department of Mechanical Engineering - Bioengineering Research Center - University of Kansas - Lawrence - KS
| | | | - Fábio Sene
- Department of Restorative Dentistry - State University of Londrina - School of Dentistry - Londrina - Brazil
| | - Sérgio Eduardo de Paiva Gonçalves
- Department of Restorative Dentistry - School of Dentistry of São José dos Campos - UNESP - Univ Estadual Paulista - São José dos Campos - SP - Brazil
| | - Jennifer Laurence
- Department of Pharmaceutical Chemistry - University of Kansas - Lawrence - KS
| |
Collapse
|
36
|
De Munck J, Mine A, Vivan Cardoso M, De Almeida Neves A, Van Landuyt KL, Poitevin A, Van Meerbeek B. Effect of dentin location and long-term water storage on bonding effectiveness of dentin adhesives. Dent Mater J 2011; 30:7-13. [PMID: 21282894 DOI: 10.4012/dmj.2010-085] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Dentin is a variable substrate with properties that change considerable in a single surface. The purpose of this study was to evaluate the bonding effectiveness to these different dentin locations and evaluate these differences over time. After bonding procedures with five different adhesives, small micro-tensile bond strength (µTBS) beams were prepared and dichotomously divided in 'center' and 'periphery' dentin specimens. After 1 week, 3, 6 and 12 months of water storage the µTBS of specimens of each group was determined, enabling a paired study design. The bond strengths of both etch&rinse adhesives were insensitive to regional variability. For the two-step self-etch adhesives, a marked increase in bond strengths was observed with increasing amount of intertubular dentin. Regional variability did not affect the long-term bonding effectiveness for any of the adhesives tested. In conclusion, only for the mild self-etch adhesives, µTBS to 'periphery' dentin was higher than for the 'center' specimens.
Collapse
Affiliation(s)
- Jan De Munck
- Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-facial Surgery, Catholic University of Leuven, Belgium.
| | | | | | | | | | | | | |
Collapse
|
37
|
Singh V, Misra A, Marangos O, Park J, Ye Q, Kieweg SL, Spencer P. Fatigue life prediction of dentin-adhesive interface using micromechanical stress analysis. Dent Mater 2011; 27:e187-95. [PMID: 21700326 DOI: 10.1016/j.dental.2011.05.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 03/27/2011] [Accepted: 05/30/2011] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The objective of this work was to develop a methodology for the prediction of fatigue life of the dentin-adhesive (d-a) interface. METHODS At the micro-scale, the d-a interface is composed of dissimilar material components. Under global loading, these components experience different local stress amplitudes. The overall fatigue life of the d-a interface is, therefore, determined by the material component that has the shortest fatigue life under local stresses. Multiple 3d finite element (FE) models were developed to determine the stress distribution within the d-a interface by considering variations in micro-scale geometry, material composition and boundary conditions. The results from these models were analyzed to obtain the local stress concentrations within each d-a interface component. By combining the local stress concentrations and experimentally determined stress versus number of cycle to failure (S-N) curves for the different material components, the overall fatigue life of the d-a interface was predicted. RESULTS The fatigue life was found to be a function of the applied loading amplitude, boundary conditions, microstructure and the mechanical properties of the material components of the d-a interface. In addition, it was found that the overall fatigue life of the d-a interface is not determined by the weakest material component. In many cases, the overall fatigue life was determined by the adhesive although exposed collagen was the weakest material component. Comparison of the predicted results with experimental data from the literature showed both qualitative and quantitative agreement. SIGNIFICANCE The methodology developed for fatigue life prediction can provide insight into the mechanisms that control degradation of the bond formed at the d-a interface.
Collapse
Affiliation(s)
- Viraj Singh
- Mechanical Engineering Department, University of Kansas, USA
| | | | | | | | | | | | | |
Collapse
|
38
|
Martini AP, Anchieta RB, Rocha EP, Freitas Junior AC, Almeida EOD, Sundfeld RH, Luersen MA. Influence of voids in the hybrid layer based on self-etching adhesive systems: a 3-D FE analysis. J Appl Oral Sci 2011; 17 Suppl:19-26. [PMID: 21499651 PMCID: PMC5467381 DOI: 10.1590/s1678-77572009000700005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 03/25/2010] [Indexed: 11/21/2022] Open
Abstract
The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL) with voids based on a self-etching adhesive system using 3-D finite element (FE) analysis. Material and Methods: Three Fe models (Mr) were built: Mr, dentin specimen (41x41x82 μm) with a regular and perfect (i.e. pore-free) HL based on a self-etching adhesive system, restored with composite resin; Mp, similar to M, but containing 25% (v/v) voids in the HL; Mpp, similar to Mr, but containing 50% (v/v) voids in the HL. A tensile load (0.03N) was applied on top of the composite resin. The stress field was obtained by using Ansys Workbench 10.0. The nodes of the base of the specimen were constrained in the x, y and z axes. The maximum principal stress (σmax) was obtained for all structures at the dentin/adhesive interface. Results: The Mpp showed the highest peak of σmax in the HL (32.2 MPa), followed by Mp (30 MPa) and Mr (28.4 MPa). The stress concentration in the peritubular dentin was high in all models (120 MPa). All other structures positioned far from voids showed similar increase of stress. Conclusion: Voids incorporated into the HL raised the σmax in this region by 13.5%. This behavior might be responsible for lower bond strengths of self-etching and single-bottle adhesives, as reported in the literature.
Collapse
|
39
|
Singh V, Misra A, Marangos O, Park J, Ye Q, Kieweg SL, Spencer P. Viscoelastic and fatigue properties of model methacrylate-based dentin adhesives. J Biomed Mater Res B Appl Biomater 2011; 95:283-90. [PMID: 20848661 DOI: 10.1002/jbm.b.31712] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The objective of the current study is to characterize the viscoelastic and fatigue properties of model methacrylate-based dentin adhesives under dry and wet conditions. Static, creep, and fatigue tests were performed on cylindrical samples in a 3-point bending clamp. Static results showed that the apparent elastic modulus of the model adhesive varied from 2.56 to 3.53 GPa in the dry condition, and from 1.04 to 1.62 GPa in the wet condition, depending upon the rate of loading. Significant differences were also found for the creep behavior of the model adhesive under dry and wet conditions. A linear viscoelastic model was developed by fitting the adhesive creep behavior. The developed model with 5 Kelvin Voigt elements predicted the apparent elastic moduli measured in the static tests. The model was then utilized to interpret the fatigue test results. It was found that the failure under cyclic loading can be due to creep or fatigue, which has implications for the failure criterion that are applied for these types of tests. Finally, it was found that the adhesive samples tested under dry conditions were more durable than those tested under wet conditions.
Collapse
Affiliation(s)
- Viraj Singh
- Mechanical Engineering Department, University of Kansas, Lawrence, Kansas 66045-7609, USA
| | | | | | | | | | | | | |
Collapse
|
40
|
Rocha EP, Anchieta RB, Freitas-Junior AC, de Almeida EO, Cattaneo PM, Ko CC. Mechanical behavior of ceramic veneer in zirconia-based restorations: A 3- dimensional finite element analysis using microcomputed tomography data. J Prosthet Dent 2011; 105:14-20. [DOI: 10.1016/s0022-3913(10)60184-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
41
|
Spencer P, Ye Q, Park J, Topp EM, Misra A, Marangos O, Wang Y, Bohaty BS, Singh V, Sene F, Eslick J, Camarda K, Katz JL. Adhesive/Dentin interface: the weak link in the composite restoration. Ann Biomed Eng 2010; 38:1989-2003. [PMID: 20195761 PMCID: PMC2871971 DOI: 10.1007/s10439-010-9969-6] [Citation(s) in RCA: 294] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Accepted: 02/12/2010] [Indexed: 11/30/2022]
Abstract
Results from clinical studies suggest that more than half of the 166 million dental restorations that were placed in the United States in 2005 were replacements for failed restorations. This emphasis on replacement therapy is expected to grow as dentists use composite as opposed to dental amalgam to restore moderate to large posterior lesions. Composite restorations have higher failure rates, more recurrent caries, and increased frequency of replacement as compared to amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and premature failure. Under in vivo conditions the bond formed at the adhesive/dentin interface can be the first defense against these noxious, damaging substances. The intent of this article is to review structural aspects of the clinical substrate that impact bond formation at the adhesive/dentin interface; to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface.
Collapse
Affiliation(s)
- Paulette Spencer
- Department of Mechanical Engineering, University of Kansas, 1530 W 15th St, Lawrence, KS 66045, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Liu HL, Lin CL, Sun MT, Chang YH. 3D micro-crack propagation simulation at enamel/adhesive interface using FE submodeling and element death techniques. Ann Biomed Eng 2010; 38:2004-12. [PMID: 20414728 DOI: 10.1007/s10439-010-0047-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Accepted: 04/13/2010] [Indexed: 11/29/2022]
Abstract
This study investigates micro-crack propagation at the enamel/adhesive interface using finite element (FE) submodeling and element death techniques. A three-dimensional (3D) FE macro-model of the enamel/adhesive/ceramic subjected to shear bond testing was generated and analyzed. A 3D micro-model with interfacial bonding structure was constructed at the upper enamel/adhesive interface where the stress concentration was found from the macro-model results. The morphology of this interfacial bonding structure (i.e., resin tag) was assigned based on resin tag geometry and enamel rod arrangement from a scanning electron microscopy micrograph. The boundary conditions for the micro-model were determined from the macro-model results. A custom iterative code combined with the element death technique was used to calculate the micro-crack propagation. Parallel experiments were performed to validate this FE simulation. The stress concentration within the adhesive occurred mainly at the upper corner near the enamel/adhesive interface and the resin tag base. A simulated fracture path was found at the resin tag base along the enamel/adhesive interface. A morphological observation of the fracture patterns obtained from in vitro testing corresponded with the simulation results. This study shows that the FE submodeling and element death techniques could be used to simulate the 3D micro-stress pattern and the crack propagation noted at the enamel/adhesive interface.
Collapse
Affiliation(s)
- Heng-Liang Liu
- Department of Mechanical Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, 33302 Tao-Yuan, Taiwan.
| | | | | | | |
Collapse
|
43
|
Anchieta RB, Rocha EP, Ko CC, Sundfeld RH, Martin Junior M, Archangelo CM. Localized mechanics of dentin self-etching adhesive system. J Appl Oral Sci 2009; 15:321-6. [PMID: 19089152 DOI: 10.1590/s1678-77572007000400015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Accepted: 08/02/2007] [Indexed: 11/22/2022] Open
Abstract
The bond strength of composite resins (CRs) to dentin is influenced by the interfacial microstructure of the hybrid layer (HL) and the resin tags (TAG). The contemporary self-etching primer adhesive systems overcame the inconvenient of the etch-and-rinse protocol. Studies, however, have demonstrated that HL thickness and TAG length vary according to the wetting time and additional use of acid-etching prior to self-etching primers. This study investigated the localized stress distribution in the HL and the dentin/adhesive interface. Two HL thicknesses (3 or 6 microm), two TAG lengths (13 or 17 microm) and two loading conditions (perpendicular and oblique-25 degrees) were investigated by the finite element (FE) analysis. Five two-dimensional FE models (M) of a dentin specimen restored with CR (38 x 64 microm) were constructed: M1 - no HL and no TAG; M2 - 3 microm of HL and 13 microm of TAG; M3 - 3 microm of HL and 17 microm of TAG; M4 - 6 microm of HL and 13 microm of TAG; and M5 - 6 microm of HL and 17 microm of TAG. Two distributed loadings (L) (20N) were applied on CR surface: L1 - perpendicular, and L2 - oblique (25 masculine). Fixed interfacial conditions were assigned on the border of the dentin specimen. Ansys 10.0 (Ansys, Houston, PA, USA) software was used to calculate the stress fields. The peak of von Mises (sigma(vM)) and maximum principal stress (sigma(max)) was higher in L2 than in L1. Microstructures (HL and TAG) had no effect on local stresses for L1. Decreasing HL decreased sigma(vM) and sigma(max) in all structures for L2, but the TAG length had influence only on the peributular dentin. The thickness of HL had more influence on the sigma(vM) and sigma(max) than TAG length. The peritubular dentin and its adjacent structures showed the highest sigma(vM) and sigma(max), mainly in the oblique loading.
Collapse
|
44
|
Liu HL, Lin CL, Sun MT, Chang YH. Numerical investigation of macro- and micro-mechanics of a ceramic veneer bonded with various cement thicknesses using the typical and submodeling finite element approaches. J Dent 2008; 37:141-8. [PMID: 19084316 DOI: 10.1016/j.jdent.2008.10.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 10/11/2008] [Accepted: 10/27/2008] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES This study investigates the influence of cement thickness on the macro- and micro-mechanical responses in a ceramic veneer adjacent to an incisal overlapped incisor. METHODS Seven finite element (FE) ceramic veneer macro-models with different cement thicknesses (10-180mum) were generated. A 10N load was applied with an angulation of 60 degrees to the longitudinal tooth axis. Seven FE micro-models corresponding to the macro-models were constructed at an enamel-adhesive interface where the stress concentration was found. Based on an interfacial scanning electron microscope (SEM) micrograph, morphology of resin tags in the micro-models was generated. The micro-model boundary conditions were determined from the macro-model results. The principal stress on each node in the macro- and micro-models was calculated to investigate interfacial mechanics. A tensile test was performed to obtain an ultimate cement tensile strength to determine the material failure parameters. RESULTS The highest stress concentration within the cement was found at the resin tag base of the enamel-adhesive interface in lingual side. Maximum stress values from 10.6 to 14.7MPa for the micro-models were higher (44-48%) than that from 7.2 to 10.0MPa for the macro-models when the cement layers increased. Based on the ultimate tensile strength (11.8MPa), bonding failure could found when the micro-models with the cement layers presented more than about 50mum. This seems to correspond with data from previous studies. CONCLUSIONS Higher stresses develop in the adhesive as the cement thickness increases. Cement thicknesses less than 50mum might reduce the adhesive bonding failure.
Collapse
Affiliation(s)
- Heng-Liang Liu
- Graduate Institute of Mechanical Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 33302, Taiwan.
| | | | | | | |
Collapse
|
45
|
Borges AFS, Bittar RA, Pascon FM, Sobrinho LC, Martin AA, Puppin Rontani RM. NaOCl effects on primary and permanent pulp chamber dentin. J Dent 2008; 36:745-53. [DOI: 10.1016/j.jdent.2008.05.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 05/14/2008] [Accepted: 05/14/2008] [Indexed: 11/29/2022] Open
|
46
|
Santhosh L, Bashetty K, Nadig G. The influence of different composite placement techniques on microleakage in preparations with high C- factor: An in vitro study. J Conserv Dent 2008; 11:112-6. [PMID: 20142897 PMCID: PMC2813100 DOI: 10.4103/0972-0707.45249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2008] [Revised: 04/07/2008] [Accepted: 05/14/2008] [Indexed: 11/14/2022] Open
Abstract
Objective: This study evaluated the marginal leakage around class-I cavity preparations restored with Nanofilled composite (Filtek Z-350 A2 shade, 3M ESPE, USA) and a self-etch adhesive (Xeno III, DENTSPLY/Caulk) using different composite placement techniques. Materials and Methods: Standardized class-I cavities were prepared on 36 caries-free, extracted human premolars and were randomly assigned to three groups: (1) Horizontal incremental curing was done; each increment of thickness 1.5 mm was cured one after the other using curing unit (T-LED, Elca Technology, Italy). (2) Concave surface was obtained with a ball burnisher on the first increment and cured for 20 seconds; subsequently, the next increment was placed and similarly cured. (3) Cavities were filled with resin, short of the occlusal surface; two cuts (mesiodistal and buccolingual) were made through the condensed resin and cured for 20 seconds, followed by addition of resin in the gaps created by the cuts and additional curing for 20 seconds. The specimens were stored in distilled water for three months and then subjected to thermocycling, followed by immersion in 0.5% methylene blue dye for 24 hours. The teeth were sectioned longitudinally and evaluated for microleakage under stereomicroscope, and the scores obtained were analysed with Fisher Exact test and Kruskal-Wallis nonparametric test. Results: There was no statistically significant difference among three groups. Conclusion: None of the techniques was capable of eliminating the microleakage in preparations with a high C-factor.
Collapse
Affiliation(s)
- Lekha Santhosh
- The Oxford Dental College and Hospital, Bommanahalli, Bangalore, Karnataka, India
| | | | | |
Collapse
|
47
|
Wood JD, Sobolewski P, Thakur V, Arola D, Nazari A, Tay FR, Pashley DH. Measurement of microstrains across loaded resin-dentin interfaces using microscopic moiré interferometry. Dent Mater 2007; 24:859-66. [PMID: 18045678 DOI: 10.1016/j.dental.2007.10.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 10/10/2007] [Accepted: 10/13/2007] [Indexed: 10/22/2022]
Abstract
UNLABELLED Little is known about the mechanical behavior of resin-dentin interfaces during loading. The presence of relatively compliant hybrid and adhesive layers between stiffer dentin and resin composite should deform more during compressive loading. OBJECTIVE The objective of this study was to measure changes in microstrain across bonded dentin interfaces in real time using a recently developed microscope moiré interferometer. METHOD This system used a miniature moiré interferometer, using two CCD cameras for simultaneous recording of longitudinal and transverse deformation fields, a piezotransducer for fringe shifting and use of a microscope objective with magnification up to 600 x. Small beams (1 mm x 2 mm x 6 mm) of moist resin-bonded dentin covered with cross-lined diffraction grating replica were placed in a miniature compression tester to allow controlled loading from 2 to 37 N while imaging the interference fringe patterns. RESULTS Resin-dentin interfaces created by bonding dentin with Single Bond/Z100, under compressive loading, exhibited comparatively large strains across the adhesive-hybrid interface. When the wrapped phase maps were unwrapped to permit conversion of fringe order to displacements, the 2-D profiles of strain fields revealed non-uniform strains across the adhesive interface. In the adhesive/hybrid layer zone, the negative strain was larger (i.e. -6000 mu epsilon) than that seen in the adjacent resin composite or underlying mineralized dentin. The changes were elastic because they disappeared when the load was removed. SIGNIFICANCE Microscopic moiré interferometry can be very useful in revealing real-time strain across bonded interfaces under load.
Collapse
Affiliation(s)
- Judy D Wood
- Mechanical Engineering Department, Clemson University, Clemson, SC, USA
| | | | | | | | | | | | | |
Collapse
|
48
|
Anchieta RB, Rocha EP, Ko CC, Sundfeld RH, Martin M, Archangelo CM. Localized mechanics of dentin self-etching adhesive system. J Appl Oral Sci 2007. [PMID: 19089152 PMCID: PMC4327437 DOI: 10.1590/s1678-775720070004000015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The bond strength of composite resins (CRs) to dentin is influenced by the interfacial microstructure of the hybrid layer (HL) and the resin tags (TAG). The contemporary self-etching primer adhesive systems overcame the inconvenient of the etch-and-rinse protocol. Studies, however, have demonstrated that HL thickness and TAG length vary according to the wetting time and additional use of acid-etching prior to self-etching primers. This study investigated the localized stress distribution in the HL and the dentin/adhesive interface. Two HL thicknesses (3 or 6 microm), two TAG lengths (13 or 17 microm) and two loading conditions (perpendicular and oblique-25 degrees) were investigated by the finite element (FE) analysis. Five two-dimensional FE models (M) of a dentin specimen restored with CR (38 x 64 microm) were constructed: M1 - no HL and no TAG; M2 - 3 microm of HL and 13 microm of TAG; M3 - 3 microm of HL and 17 microm of TAG; M4 - 6 microm of HL and 13 microm of TAG; and M5 - 6 microm of HL and 17 microm of TAG. Two distributed loadings (L) (20N) were applied on CR surface: L1 - perpendicular, and L2 - oblique (25 masculine). Fixed interfacial conditions were assigned on the border of the dentin specimen. Ansys 10.0 (Ansys, Houston, PA, USA) software was used to calculate the stress fields. The peak of von Mises (sigma(vM)) and maximum principal stress (sigma(max)) was higher in L2 than in L1. Microstructures (HL and TAG) had no effect on local stresses for L1. Decreasing HL decreased sigma(vM) and sigma(max) in all structures for L2, but the TAG length had influence only on the peributular dentin. The thickness of HL had more influence on the sigma(vM) and sigma(max) than TAG length. The peritubular dentin and its adjacent structures showed the highest sigma(vM) and sigma(max), mainly in the oblique loading.
Collapse
Affiliation(s)
| | - Eduardo Passos Rocha
- Ph.D, Department of Dental Materials and Prosthodontics, Dental School of Araçatuba, São Paulo State University, Araçatuba, SP, Brazil,Corresponding address: Prof. Eduardo Passos Rocha - Departamento de Materiais Dentários e Prótese - Rua Jose Bonifacio, 1193 - 16015-050 Aracatuba, Sao Paulo, Brazil - Phone/Fax number: +55 18 3636-3245 - e-mail:
| | - Ching-Chang Ko
- Ph.D, Department of Orthodontics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Renato Herman Sundfeld
- Ph.D, Department of Restorative Dentistry, Dental School of Araçatuba, São Paulo State University, Araçatuba, SP, Brazil
| | - Manoel Martin
- MS, Ph.D student, Department of Dental Materials and Prosthodontics, Dental School of Araçatuba, São Paulo State University, Araçatuba, SP, Brazil
| | - Carlos Marcelo Archangelo
- MS, Ph.D student, Department of Dental Materials and Prosthodontics, Dental School of Araçatuba, São Paulo State University, Araçatuba, SP, Brazil
| |
Collapse
|
49
|
Moreira da Silva E, dos Santos GO, Guimarães JGA, Barcellos ADAL, Sampaio EM. The Influence of C-factor, Flexural Modulus and Viscous Flow on Gap Formation in Resin Composite Restorations. Oper Dent 2007; 32:356-62. [PMID: 17695608 DOI: 10.2341/06-104] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinical Relevance
Resin composites with high viscous flow and low flexural modulus may reduce gap formation in resin composite restorations.
Collapse
Affiliation(s)
- Eduardo Moreira da Silva
- Department of Restorative Dentistry, School of Dentistry, Federal Fluminense University, Rio De Janeiro, Brazil.
| | | | | | | | | |
Collapse
|
50
|
Katz JL, Misra A, Spencer P, Wang Y, Bumrerraj S, Nomura T, Eppell SJ, Tabib-Azar M. Multiscale mechanics of hierarchical structure/property relationships in calcified tissues and tissue/material interfaces. MATERIALS SCIENCE & ENGINEERING. A, STRUCTURAL MATERIALS : PROPERTIES, MICROSTRUCTURE AND PROCESSING 2007; 27:450-468. [PMID: 18270549 PMCID: PMC2239254 DOI: 10.1016/j.msec.2006.05.055] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This paper presents a review plus new data that describes the role hierarchical nanostructural properties play in developing an understanding of the effect of scale on the material properties (chemical, elastic and electrical) of calcified tissues as well as the interfaces that form between such tissues and biomaterials. Both nanostructural and microstructural properties will be considered starting with the size and shape of the apatitic mineralites in both young and mature bovine bone. Microstructural properties for human dentin and cortical and trabecular bone will be considered. These separate sets of data will be combined mathematically to advance the effects of scale on the modeling of these tissues and the tissue/biomaterial interfaces as hierarchical material/structural composites. Interfacial structure and properties to be considered in greatest detail will be that of the dentin/adhesive (d/a) interface, which presents a clear example of examining all three material properties, (chemical, elastic and electrical). In this case, finite element modeling (FEA) was based on the actual measured values of the structure and elastic properties of the materials comprising the d/a interface; this combination provides insight into factors and mechanisms that contribute to premature failure of dental composite fillings. At present, there are more elastic property data obtained by microstructural measurements, especially high frequency ultrasonic wave propagation (UWP) and scanning acoustic microscopy (SAM) techniques. However, atomic force microscopy (AFM) and nanoindentation (NI) of cortical and trabecular bone and the dentin-enamel junction (DEJ) among others have become available allowing correlation of the nanostructural level measurements with those made on the microstructural level.
Collapse
Affiliation(s)
- J. Lawrence Katz
- School of Computing and Engineering, University of Missouri-Kansas City, Kansas City, MO, USA
- School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Anil Misra
- School of Computing and Engineering, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Paulette Spencer
- School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Yong Wang
- School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | | | | | - Steven J. Eppell
- Case School of Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Massood Tabib-Azar
- Case School of Engineering, Case Western Reserve University, Cleveland, OH, USA
| |
Collapse
|