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Marques JA, Falacho RI, Santos JM, Ramos JC, Palma PJ. Effects of endodontic irrigation solutions on structural, chemical, and mechanical properties of coronal dentin: A scoping review. J ESTHET RESTOR DENT 2024; 36:606-619. [PMID: 37698359 DOI: 10.1111/jerd.13135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/13/2023]
Abstract
OBJECTIVE This review aims to assess structural, chemical, and mechanical properties of coronal dentin after endodontic irrigation. MATERIALS AND METHODS Reporting followed the PRISMA extension for scoping reviews. An electronic search was carried out in PubMed, Embase, and Cochrane Library. Records filtered by language and published up to November 4, 2022 were independently screened by two researchers. Studies evaluating structural, chemical, or mechanical properties of human permanent coronal dentin after irrigation within the scope of nonsurgical root canal treatment were included. Data were extracted regarding study type, sample description and size, experimental groups, outcome, evaluation method, and main findings. RESULTS From the initial 1916 studies, and by adding 2 cross-references, 11 in vitro studies were included. Seven studies provide ultrastructural and/or chemical characterization, and six assessed microhardness and/or flexural strength. One percent to 8% sodium hypochlorite (NaOCl) and 1%-17% ethylenediaminetetraacetic acid (EDTA) were the most commonly tested solutions, with contact times of 2-240 min (NaOCl) and 1-1440 min (EDTA) being evaluated. CONCLUSIONS Overall, the literature is consensual regarding the inevitable impact of NaOCl and chelating agents on coronal dentin, with both deproteinizing and decalcifying effects being concentration- and time-dependent. The alteration of mechanical parameters further confirmed the surface and subsurface ultrastructural and chemical changes. CLINICAL SIGNIFICANCE Endodontic treatment success highly depends on restorative sealing. Understanding the result of exposing coronal dentin, the main substrate for bonding, to irrigants' action is crucial. The deproteinizing and decalcifying effects of NaOCl and chelating agents are both concentration- and time-dependent, causing surface and subsurface ultrastructural, chemical, and mechanical alterations.
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Affiliation(s)
- Joana A Marques
- Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rui I Falacho
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Institute of Oral Implantology and Prosthodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - João Miguel Santos
- Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Coimbra Institute for Clinical and Biomedical Research (iCBR) and Center of Investigation on Environment Genetics and Oncobiology (CIMAGO), Faculty of Medicine and Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
| | - João Carlos Ramos
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Institute of Operative Dentistry, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Paulo J Palma
- Institute of Endodontics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Yi Q, Feng X, Zhang C, Wang X, Wu X, Wang J, Cui F, Wang S. Comparison of dynamic mechanical properties of dentin between deciduous and permanent teeth. Connect Tissue Res 2021; 62:402-410. [PMID: 32308055 DOI: 10.1080/03008207.2020.1758684] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose: Even though differences between deciduous and permanent dentin have been widely studied, their dynamic mechanical behavior has never been compared. The objective of the present study was to quantify the differences between deciduous and permanent dentin under cyclic mechanical loading, which is similar to masticatory stress.Materials and Methods: Deciduous and permanent teeth, respectively from children (9 ~ 12 years old) and young people (18 ~ 25 years old), were wet-sectioned perpendicular to the longitudinal axis and the central specimens of coronal dentin were evaluated by nanoscopic dynamic mechanical analysis (nanoDMA).Results: The average storage, loss, and complex moduli, as well as the hardness of deciduous dentin were significantly (p < 0.05) lower than those of permanent dentin. Moreover, the tan δ value of permanent dentin was significantly (p < 0.05) lower than that of deciduous dentin across the loading frequency range, indicating that viscoelastic behavior and loss of elastic energy were significantly reduced in the stiffer permanent dentin. All the nanoDMA responses showed a significant influence of the dynamic loading frequency (p < 0.05): Both deciduous and permanent dentin showed reduced viscoelasticty with increased loading frequencies.Conclusions: Compared with deciduous dentin, permanent dentin exhibits higher stiffness with reduced energy loss during deformation, and therefore superior mechanical characteristics for the mastication process.
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Affiliation(s)
- Qiao Yi
- Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, P. R. China
| | - Xiaoyu Feng
- Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, P. R. China
| | - Chunmei Zhang
- Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, P. R. China
| | - Xiumei Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, P. R. China
| | - Xiaoshan Wu
- Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, P. R. China.,Department of Oral and Maxillofacial Surgery, Xiangya Hospital, Central South University, Shangsha, China
| | - Jingsong Wang
- Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, P. R. China.,Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, Beijing, P. R. China
| | - Fuzhai Cui
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, P. R. China
| | - Songlin Wang
- Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, P. R. China.,Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, Beijing, P. R. China
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Maghami E, Pejman R, Najafi AR. Fracture micromechanics of human dentin: A microscale numerical model. J Mech Behav Biomed Mater 2020; 114:104171. [PMID: 33218927 DOI: 10.1016/j.jmbbm.2020.104171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/17/2020] [Accepted: 10/23/2020] [Indexed: 11/25/2022]
Abstract
In the present study, we investigate the effects of microstructural morphology and heterogeneity on the initiation and propagation of microcracks in dentin. We create 2D pre-cracked models of human dentin at the microscale level and use a brittle fracture framework of the phase-field method to analyze the crack growth. We discuss the influence of the microstructural features on crack deflection, microcracking, and uncracked ligament bridging through various regions in dentin. The results demonstrate that the difference between the critical energy release rates of peritubular (PTD) and intertubular dentin (ITD) has considerable impacts on microcracking. Our simulations reveal that tubules surrounded by PTDs play an important role in the crack deflection. Our results also indicate that the toughness of dentin increases from the inner to outer dentin. In conclusion, the findings in our study provide valuable insights into the fracture behavior in various regions of dentin.
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Affiliation(s)
- Ebrahim Maghami
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, 19104, USA
| | - Reza Pejman
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, 19104, USA
| | - Ahmad R Najafi
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, 19104, USA.
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4
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Thompson VP. The tooth: An analogue for biomimetic materials design and processing. Dent Mater 2020; 36:25-42. [DOI: 10.1016/j.dental.2019.08.106] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 08/21/2019] [Accepted: 08/28/2019] [Indexed: 01/05/2023]
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Pedersen ND, Uzunoglu-Özyürek E, Dogan Buzoglu H. Influence of different irrigation protocols on microhardness and flexural strength values of young and aged crown dentin. Gerodontology 2019; 37:53-58. [PMID: 31746036 DOI: 10.1111/ger.12444] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 08/26/2019] [Accepted: 10/18/2019] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate the effect of different irrigation protocols on microhardness (MH) and flexural strength (FS) values of young and aged crown dentin. BACKGROUND In addition to ageing, root canal irrigation might also affect the mechanical properties of coronal dentin walls. MATERIALS AND METHODS One hundred and twenty dentin bars (2 mm × 2 mm × 8 mm) were obtained from the crowns of extracted, non-caries, human molars of young and older patients (n = 60 bars; average patient ages: 16.7 and 65.4, respectively). Subgroups were formed as follows: 2.5%NaOCl(sodium hypochlorite)+5%EDTA(ethylenediaminetetraacetic acid), 2.5%NaOCl + 15%EDTA, 2.5%NaOCl, 5%EDTA, 15%EDTA and Saline. NaOCl and saline were used for 20 minutes and EDTA solutions for 1 minute. MH values of each sample were measured before and after the irrigation protocols. The same samples were also submitted for FS analysis. The data were statistically analysed. RESULTS Young samples had lower MH values at pre- and post-treatment compared to aged samples (P < .05). A significant decrease was observed in MH values of aged samples exposed to 2.5%NaOCl and both NaOCl + EDTA combinations (P < .05). FS values of the young saline-treated group were statistically higher than aged ones (P < .05). Both NaOCl + EDTA combinations caused a significant decrease in FS values of young samples compared to saline (P < .05). CONCLUSION Ageing has a significant effect on the MH and FS values of crown dentin samples. 5% EDTA solutions revealed similar results to 15%EDTA regarding MH and FS values of crown dentin in both age groups. The NaOCl + EDTA combination had a prominent effect than EDTA alone, on MH values of young-, and FS values of aged dentin samples.
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Affiliation(s)
- Nurab Deniz Pedersen
- Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey
| | - Emel Uzunoglu-Özyürek
- Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey
| | - Hatice Dogan Buzoglu
- Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey
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Cochrane S, Burrow MF, Parashos P. Effect on the mechanical properties of human and bovine dentine of intracanal medicaments and irrigants. Aust Dent J 2018; 64:35-42. [DOI: 10.1111/adj.12655] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2018] [Indexed: 11/28/2022]
Affiliation(s)
- S Cochrane
- The Melbourne Dental School; Faculty of Medicine; Dentistry and Health Sciences; The University of Melbourne; Melbourne Victoria Australia
| | - MF Burrow
- The Melbourne Dental School; Faculty of Medicine; Dentistry and Health Sciences; The University of Melbourne; Melbourne Victoria Australia
| | - P Parashos
- The Melbourne Dental School; Faculty of Medicine; Dentistry and Health Sciences; The University of Melbourne; Melbourne Victoria Australia
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Alonso JRL, Basso FG, Scheffel DLS, de-Souza-Costa CA, Hebling J. Effect of crosslinkers on bond strength stability of fiber posts to root canal dentin and in situ proteolytic activity. J Prosthet Dent 2017; 119:494.e1-494.e9. [PMID: 29195822 DOI: 10.1016/j.prosdent.2017.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 08/01/2017] [Accepted: 08/01/2017] [Indexed: 10/18/2022]
Abstract
STATEMENT OF PROBLEM Improved stability of the adhesive interface can be obtained using crosslinkers. However, research on the use of crosslinkers in root dentin is lacking. PURPOSE The purpose of this in vitro study was to evaluate the effect of crosslinkers on the proteolytic activity of root dentin and on the bond strength of resin-cemented fiber posts. MATERIAL AND METHODS Single root canals were obtained from premolars (n=48) and endodontically treated before being divided into 4 groups: deionized water (control), 0.5 mol/L carbodiimide, 5% proanthocyanidin, or 5% glutaraldehyde. After removing the canal sealer, the dentin was etched with phosphoric acid, followed by water rinsing and the application of the crosslinkers for 60 seconds. Fiber posts were cemented using an adhesive (Single Bond 2) and resin cement (RelyX ARC). The roots were then transversally sectioned to obtain 1 mm thick specimens from the cervical, middle, and apical thirds and then aged for 24 hours or 9 months. Nine roots per group were used for the push-out test and 3 for determining the proteolytic activity of the root dentin by in situ zymography. Bond strength data were submitted to a mixed-model ANOVA and Bonferroni tests (α=.05). RESULTS Only proanthocyanidin negatively affected the 24-hour bond strength. After 9 months, a significant decrease in bond strength was seen for all groups, except for the crosslinked treated specimens from the cervical third of the root canal. Intense gelatinolytic activity was detected in the control group after 24 hours but was inhibited in the crosslinker-treated groups. Proteolytic activity was also not detected after 9 months for the groups treated with the crosslinkers, irrespective of the root canal third. Conversely, proteolytic activity increased for the specimens from the control group. CONCLUSIONS Although no proteolytic activity was detected in the hybrid layers along the entire root canal, dentin biomodification with crosslinkers was effective in preventing bond strength loss only in the cervical third.
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Affiliation(s)
- Juliana R L Alonso
- Assistant researcher, Department of Oral Rehabilitation, São Paulo State University (UNESP), School of Dentistry, São Paulo, Brazil
| | - Fernanda G Basso
- Postdoctoral researcher, Department of Physiology and Pathology, São Paulo State University (UNESP), School of Dentistry, São Paulo, Brazil
| | - Débora L S Scheffel
- Postdoctoral researcher, Department of Pediatric Dentistry and Orthodontics, São Paulo State University (UNESP), School of Dentistry, São Paulo, Brazil
| | - Carlos Alberto de-Souza-Costa
- Professor, Department of Physiology and Pathology, São Paulo State University (UNESP), School of Dentistry, São Paulo, Brazil
| | - Josimeri Hebling
- Professor, Department of Pediatric Dentistry and Orthodontics, São Paulo State University (UNESP), School of Dentistry, São Paulo, Brazil.
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The Elasticity Coefficients Measurement of Human Dentin Based on RUS. BIOMED RESEARCH INTERNATIONAL 2017; 2017:7852971. [PMID: 28540302 PMCID: PMC5429957 DOI: 10.1155/2017/7852971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 04/05/2017] [Indexed: 11/19/2022]
Abstract
This paper proposed to take advantages of resonant ultrasound spectroscopy (RUS) to measure the mechanical properties of human dentin specimen. The resonant spectroscopy of the dentin specimen was obtained between the frequency bands 155 and 575 kHz, and resonant frequencies were extracted by linear predictive filter and then by Levenberg-Marquardt method. By inverse problem approach, 13 experimental resonant frequencies progressively matched to the first 30 orders of theoretical resonant frequencies calculated by Lagrangian variational method. The full second-order elastic tensor of dentin specimen was adjusted. The whole set of human dentin engineering moduli, including Young's moduli (E11 = 22.641 GPa, E33 = 13.637 GPa), shear moduli (G12 = 10.608 GPa, G23 = 7.742 Gpa), and Poisson's ratios (ν12 = 0.067, ν31 = 0.378), were finally calculated. This study demonstrates that RUS can be successfully adapted to measure the mechanical properties of low quality factor biomaterials.
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Basting RT, Leme AA, Bridi EC, Amaral FLBD, França FMG, Turssi CP, Bedran-Russo AK. Nanomechanical properties, SEM, and EDS microanalysis of dentin treated with 2.5% titanium tetrafluoride, before and after an erosive challenge. J Biomed Mater Res B Appl Biomater 2014; 103:783-9. [DOI: 10.1002/jbm.b.33254] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 06/29/2014] [Accepted: 07/15/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Roberta Tarkany Basting
- Department of Restorative Dentistry; São Leopoldo Mandic School of Dentistry and Research Institute; Campinas São Paulo Brazil
| | - Ariene Arcas Leme
- Department of Restorative Dentistry; College of Dentistry, University of Illinois at Chicago; Chicago Illinois
| | - Enrico Coser Bridi
- Department of Restorative Dentistry; São Leopoldo Mandic School of Dentistry and Research Institute; Campinas São Paulo Brazil
| | | | - Fabiana Mantovani Gomes França
- Department of Restorative Dentistry; São Leopoldo Mandic School of Dentistry and Research Institute; Campinas São Paulo Brazil
| | - Cecília Pedroso Turssi
- Department of Cariology ans Statistics; São Leopoldo Mandic Dental School and Research Center; Campinas São Paulo Brazil
| | - Ana Karina Bedran-Russo
- Department of Restorative Dentistry; College of Dentistry, University of Illinois at Chicago; Chicago Illinois
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Yassen GH, Chu TMG, Gallant MA, Allen MR, Vail MM, Murray PE, Platt JA. A novel approach to evaluate the effect of medicaments used in endodontic regeneration on root canal surface indentation. Clin Oral Investig 2013; 18:1569-75. [DOI: 10.1007/s00784-013-1125-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 09/30/2013] [Indexed: 11/28/2022]
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11
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Eltit F, Ebacher V, Wang R. Inelastic deformation and microcracking process in human dentin. J Struct Biol 2013; 183:141-8. [DOI: 10.1016/j.jsb.2013.04.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/16/2013] [Accepted: 04/01/2013] [Indexed: 11/28/2022]
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12
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Barón M, Llena C, Forner L, Palomares M, González-García C, Salmerón-Sánchez M. Nanostructural changes in dentine caused by endodontic irrigants. Med Oral Patol Oral Cir Bucal 2013; 18:e733-6. [PMID: 23524430 PMCID: PMC3731106 DOI: 10.4317/medoral.18713] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 12/08/2012] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To study nanostructural dentinal changes produced by endodontic irrigants. STUDY DESIGN Experimental study. Nanoindentations were performed on peritubular (PD) and intertubular dentine (ID) with an atomic force microscopy. Stiffness and adhesion force were determined before and after application of 5.25% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA). Normalized differences before and after treatment for stiffness and adhesion forces were calculated. A paired T-test was used to compare stiffness and adhesion force before and after irrigants application. RESULTS After treatment with EDTA there was a 29.80% reduction in stiffness in ID and a 63.53% reduction in PD. Adhesion force was reduced by 21.22% and 8.21% respectively. After treatment with 5.25% NaOCI stiffness was reduced by 2.49% in ID and increased by 15.01% in PD. Adhesion force increased by 25.11% and 23.97% respectively. CONCLUSIONS 17% EDTA reduced stiffness and adhesion force in ID and PD. Treatment with NaOCI at 5.25% had no significant effect on stiffness but did affect adhesion force in ID and PD.
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Affiliation(s)
- Marta Barón
- Department of Stomatology, Universitat de València, Valencia, Spain
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Ryou H, Pashley DH, Tay FR, Arola D. A characterization of the mechanical behavior of resin-infiltrated dentin using nanoscopic Dynamic Mechanical Analysis. Dent Mater 2013; 29:719-28. [PMID: 23639453 DOI: 10.1016/j.dental.2013.03.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 01/28/2013] [Accepted: 03/22/2013] [Indexed: 11/19/2022]
Abstract
UNLABELLED This study explored the spatial variations in mechanical behavior of resin-infiltrated dentin using nanoscopic Dynamic Mechanical Analysis (DMA). OBJECTIVE The objectives were to: (1) evaluate the mechanical behavior of resin-infiltrated dentin using a scanning-based approach to nanoindentation, (2) identify contributions of the collagen matrix to time-dependent deformation of the hybrid layer, and (3) assess the importance of specimen hydration on the nanoDMA response. METHODS Specimens of completely demineralized dentin infiltrated with commercial resin adhesive and control samples of resin adhesive were evaluated using a nanoindenter in scanning mode. The load and displacement responses were used to perform DMA and to estimate the complex (E*), storage (E') and loss (E″) moduli over selected regions of evaluation. The importance of hydration on the mechanical behavior was also examined from a comparison of responses in the hydrated and dehydrated conditions. RESULTS In the hydrated state the apparent complex, storage and loss moduli for the resin-infiltrated dentin samples were 3.5±0.3GPa, 3.4±0.2GPa and 0.9±0.3GPa, respectively. Those values for the resin adhesive control were 2.7±0.3GPa, 2.7±0.3GPa and 0.2±0.02GPa, respectively. Viscoelastic deformation of the resin-infiltrated collagen exceeded that occurring in regions of uniform resin adhesive. Though dehydration resulted in a significant increase in both the complex and storage moduli of the macro hybrid layer, the largest changes occurred to the resin adhesive. SIGNIFICANCE The microstructure and hydration play critical roles on the mechanical behavior of the hybrid layer and nanoDMA provides a potent measurement tool for identifying the spatial variations.
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Affiliation(s)
- Heonjune Ryou
- Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD, USA
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Ryou H, Romberg E, Pashley DH, Tay FR, Arola D. Nanoscopic dynamic mechanical properties of intertubular and peritubular dentin. J Mech Behav Biomed Mater 2011; 7:3-16. [PMID: 22340680 DOI: 10.1016/j.jmbbm.2011.08.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 08/11/2011] [Accepted: 08/17/2011] [Indexed: 10/17/2022]
Abstract
An experimental evaluation of intertubular and peritubular dentin was performed using nanoindentation and Dynamic Mechanical Analysis (DMA). The objective of the investigation was to evaluate the differences in dynamic mechanical behavior of these two constituents and to assess whether their response is frequency dependent. Specimens of hydrated coronal dentin were evaluated by DMA using single indents over a range of parametric conditions and using scanning probe microscopy. The complex (E∗), storage (E') and loss moduli (E″) of the intertubular and peritubular dentin were evaluated as a function of the dynamic loading frequency and static load in the fully hydrated condition. The mean complex E∗ (19.6 GPa) and storage E' (19.2 GPa) moduli of the intertubular dentin were significantly lower than those for peritubular dentin (E∗ = 31.1 GPa, p < 0.05; E' = 30.3 GPa, p < 0.05). There was no significant influence of dynamic loading frequency on these measures. Although there was no significant difference in the loss modulus (E″) between the two materials (p > 0.05), both constituents exhibited a significant increase in E″ with dynamic load frequency and reduction in the quasi-static component of indentation load. The largest difference in dynamic behavior of the two tissues was noted at small quasi-static indentation loads and the highest frequency.
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Affiliation(s)
- Heonjune Ryou
- Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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Inoue T, Nishimura F, Debari K, Kou K, Miyazaki T. Fatigue and tensile properties of radicular dentin substrate. J Biomech 2011; 44:586-92. [DOI: 10.1016/j.jbiomech.2010.11.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 11/14/2010] [Accepted: 11/17/2010] [Indexed: 11/27/2022]
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Deymier-Black A, Almer J, Stock S, Haeffner D, Dunand D. Synchrotron X-ray diffraction study of load partitioning during elastic deformation of bovine dentin. Acta Biomater 2010; 6:2172-80. [PMID: 19925891 DOI: 10.1016/j.actbio.2009.11.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 11/25/2022]
Abstract
The elastic properties of dentin, a biological composite consisting of stiff hydroxyapatite (HAP) nano-platelets within a compliant collagen matrix, are determined by the volume fraction of these two phases and the load transfer between them. We have measured the elastic strains in situ within the HAP phase of bovine dentine by high energy X-ray diffraction for a series of static compressive stresses at ambient temperature. The apparent HAP elastic modulus (ratio of applied stress to elastic HAP strain) was found to be 18+/-2GPa. This value is significantly lower than the value of 44GPa predicted by the lower bound load transfer Voigt model, using HAP and collagen volume fractions determined by thermo-gravimetric analysis. This discrepancy is explained by (i) a reduction in the intrinsic Young's modulus of the nano-size HAP platelets due to the high fraction of interfacial volume and (ii) an increase in local stresses due to stress concentration around the dentin tubules.
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