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Bassiouny D, Petersmann S, Zohdy M, Morsi T, Taha D. Trueness and intaglio fit of custom-made polyetheretherketone post-and-cores fabricated using different techniques. J Prosthet Dent 2024:S0022-3913(24)00457-8. [PMID: 39089926 DOI: 10.1016/j.prosdent.2024.06.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 06/28/2024] [Accepted: 06/28/2024] [Indexed: 08/04/2024]
Abstract
STATEMENT OF PROBLEM Applications of polyetheretherketone (PEEK) as a promising alternative to ceramic materials have extended to include post-and-cores. However, information regarding the available fabrication techniques for producing custom-made PEEK post-and-cores and their effect on accuracy is still scarce. PURPOSE The purpose of this in vitro study was to evaluate the trueness and intaglio fit of custom-made PEEK post-and-cores fabricated using different techniques. MATERIAL AND METHODS Ten mandibular second premolars were collected, decoronated, and endodontically treated. For the fabrication of custom-made post-and-cores, each post space was prepared, scanned, and designed by using the exocad software program. Each reference design was used to fabricate PEEK post-and-cores with 3 different techniques (N=30): group P, heat pressing; group S, subtractive manufacturing, and group A, additive manufacturing. All the fabricated restorations were scanned, providing the test data as standard tessellation language (STL) files, which were imported with the reference data into a reverse engineering software program to evaluate the 3D trueness of each fabrication technique. To evaluate the intaglio fit, restorations coated with silicone material were scanned to provide the test data as STL files, which were superimposed on the STL files of the scanned restorations. One-way analysis of variance (ANOVA) and 2-way mixed model ANOVA tests were used to analyze the data (α=.05). RESULTS For 3D trueness, root mean square (RMS) values representing the deviations between the scans of the fabricated restorations and the reference designs varied significantly among different groups (P<.001), with the highest mean deviation found in group A (102.8 ±31 µm), while the lowest mean deviation was found in group S (42.2 ±11 µm). For the intaglio fit, the deviations between the scans of the fabricated restorations and the scans of the coated restorations varied significantly among different groups (P<.001), with the highest mean deviation found in group A (228.4 ±47 µm), while the lowest mean deviation was found in group S (96.2 ±14 µm). Simple effects comparisons showed the highest value of deviation in the apical area in group A (P<.001). CONCLUSIONS Custom-made PEEK post-and-cores fabricated by using subtractive manufacturing and heat pressing techniques showed better trueness and intaglio fit compared with additively manufactured restorations. Before printed PEEK restorations can be considered a suitable alternative to pressed or milled ones, improvements are required to confirm their reliability.
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Affiliation(s)
- Dina Bassiouny
- Assistant Lecturer, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
| | - Sandra Petersmann
- Senior Researcher, DMiRE Research Center, Carinthia University of Applied Sciences, Villach, Austria
| | - Maged Zohdy
- Professor, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
| | - Tarek Morsi
- Professor, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt; and Vice Dean of Postgraduate Affairs, Faculty of Oral and Dental Medicine, Misr International University, Cairo, Egypt
| | - Doaa Taha
- Associate Professor, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt; Associate Professor, Department of Fixed Prosthodontics, School of Dentistry, Newgiza University, Giza, Egypt; and Visiting Researcher, Section Medical Materials Science & Technology, University Hospital Tübingen, Tübingen, Germany.
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Tribst JPM, Dal Piva AMDO, Muris J, Kleverlaan CJ, Feilzer AJ. One-piece endodontic crown fixed partial denture: Is it possible? J Prosthet Dent 2024; 131:1118-1125. [PMID: 36801103 DOI: 10.1016/j.prosdent.2023.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 02/18/2023]
Abstract
STATEMENT OF PROBLEM Whether the replacement of a missing tooth with a fixed partial denture supported by an endodontically treated abutment could be improved with 1-piece endodontic crowns is unclear. PURPOSE The purpose of the study was to evaluate the mechanical behavior of a fixed partial denture (FPD) according to the preparation of the abutment teeth (1-piece endodontic crown or complete crown) in terms of stress magnitude in the prosthesis, cement layer, and tooth. MATERIAL AND METHODS A posterior model with 2 abutment teeth (first molar and first premolar) was modeled with a computer-aided design (CAD) software program for conducting a 3-dimensional finite element analysis (FEA). To replace the missing second premolar, the model was replicated in different possible FPDs according to the abutment preparation design (complete crown [Conventional], 2 1-piece endodontic crowns [EC]) or a 1-piece endodontic crown on one of the abutment teeth (first molar [ECM] and first premolar [ECP]) for a total of 4 designs. All FPDs were in lithium disilicate. The solids were imported to an analysis software program (ANSYS 19.2) in the standard for the exchange of product data (STEP) format. The mechanical properties were considered isotropic and the materials to show linear elastic and homogeneous behavior. An axial load (300 N) was applied at the occlusal surface of the pontic. The results were evaluated by colorimetric stress maps of von Mises and maximum principal stress in the prosthesis, maximum principal stress and shear stresses on the cement layer, and maximum principal stress in the abutment teeth. RESULTS The von Mises stresses revealed that all FPD designs behaved similarly and that, considering the maximum principal stress criteria, the pontic was the most stressed region. For the cement layer, the combined designs presented an intermediate behavior, with the ECM more suitable to reducing the stress peak. The conventional preparation allowed less stress concentration in both teeth, and higher stress concentration in the premolar was observed with a 1-piece endodontic crown. The 1-piece endodontic crown decreased the risk of fracture failure. Considering the risk of debonding failure for the prosthesis, the 1-piece endodontic crown preparation was only able to decrease the failure risk when the EC design was used and when only the shear stress was considered. CONCLUSIONS Performing 1-piece endodontic crown preparations to retain a 3-unit lithium disilicate FPD is an alternative to conventional complete crown preparations.
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Affiliation(s)
- João Paulo M Tribst
- Assistant Professor, Department of Oral Regenerative Medicine, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, the Netherlands
| | - Amanda Maria de O Dal Piva
- Assistant Professor, Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, the Netherlands.
| | - Joris Muris
- Assistant Professor, Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, the Netherlands
| | - Cornelis J Kleverlaan
- Professor, Department of Dental Materials Science, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam & Vrije Universiteit, Amsterdam, the Netherlands
| | - Albert J Feilzer
- Professor, Department of Oral Regenerative Medicine, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam & Vrije Universiteit, Amsterdam, the Netherlands
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Yamakami SA, Gallas JA, Petean IBF, Souza-Gabriel AE, Sousa-Neto M, Macedo AP, Palma-Dibb RG. Impact of Endodontic Kinematics on Stress Distribution During Root Canal Treatment: Analysis of Photoelastic Stress. J Endod 2021; 48:255-262. [PMID: 34699903 DOI: 10.1016/j.joen.2021.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 10/09/2021] [Accepted: 10/14/2021] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Structural defects created by endodontic treatment are the most common cause of major dental failures. This study analyzed levels of stress produced by endodontic instruments during the root canal treatment by photoelastic analysis of stress. METHODS Twenty-four human premolars were randomly divided into 4 groups (n = 6) according to instrumentation protocol: ProTaper Next (GPT), One Shape (GOS), Wave One Gold (GWO), and TF Adaptive (GTF). The evaluation of the photoelastic model was performed at 4 dental zones: dental-crown region, cervical third of root, middle third of root, and apical third of root. Silicone molds were prepared (2 × 15 mm), and pinjets were used inside the root canals to fixate teeth. Photoelastic resin (2:1 ratio) was poured into the silicone molds to form photoelastic models. A transmission polariscope was used to analyze the positions of interest and recorded with a digital camera. Tardy's method was used to quantify the fringe order (n) and calculate the maximum stress value (τ) at each selected point. Data were analyzed with two-way analysis of variance, Tukey test (P < .05), fringe descriptive analysis. RESULTS All groups showed a significant increase in the level of stress created during biomechanical preparation of the root canals. In the quantitative analysis, there was no statistically significant difference among the groups (P > .05). In the qualitative analysis, GPT and GTF instruments achieved greater levels of stresses compared with GWO and GOS instruments. At the beginning of instrumentation, stresses were concentrated at the coronary level and the end of instrumentation at the middle and apical root level. CONCLUSIONS All endodontic systems resulted in accumulation of stress along the dental structure. Stress was found in different concentrations along the tooth and at different levels.
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Affiliation(s)
- Shelyn Akari Yamakami
- Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Julia Adornes Gallas
- Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Igor Bassi Ferreira Petean
- Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Aline Evangelista Souza-Gabriel
- Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Manoel Sousa-Neto
- Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ana Paula Macedo
- Department of Dental Materials and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Regina Guenka Palma-Dibb
- Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil.
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Jafari S, Alihemmati M, Ghomi AJ, Shayegh SS, Kargar K. Stress distribution of esthetic posts in the restored maxillary central incisor: Three-dimensional finite-element analysis. Dent Res J (Isfahan) 2021; 18:10. [PMID: 34084297 PMCID: PMC8122688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/13/2020] [Accepted: 09/19/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Glass fiber posts, along with their esthetic properties, may have a better stress distribution than cast posts, Therefore, the aim of the present study was to investigate the effect of glass fiber, casting, titanium, and zirconia posts on stress distribution in maxillary central tooth treated with different amounts of ferrule using finite-element analysis. MATERIALS AND METHODS In this experimental study, three-dimensional models of maxillary central incisors that have undergone root canal treatment were designed. Then, the models were divided into four groups according to the type of post (Ni-Cr casting, glass fiber, titanium, and zirconia) used. Zirconia monolithic crowns were used in all the four groups. Ferrule heights were repeated at 0 and 2 mm in all models. Models were entered into COMSOL Metaphysics software. Then, the force of 100 N with the angle of 135° on the palatal surface was applied to the longitudinal axis of the tooth, and the stress distribution in the models was investigated. RESULTS Maximum stress was observed in the middle third of posts. Stress distribution in glass fiber post was better than zirconia and casting posts. Stress accumulation in models with zirconia, titanium, and casting posts was also found in the site between the middle third and coronal third, whereas in models with glass fiber post, stress accumulation was found between the crown and the cemento-enamel junction. In models without ferrule, stress accumulation was observed in one-third of the coronal, especially in glass fiber posts. CONCLUSION The post material and ferrule height affected stress concentration. The stress in the cervical area of the dentin was more for glass fiber post when compared to other posts. The use of glass fiber post in teeth with no ferrule results in lower stress along the post, but greater stress in the simulated tooth region.
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Affiliation(s)
- Sina Jafari
- Department of Prosthodontics, Faculty of Dentistry, Shahed University, Tehran, Iran
| | - Mohammad Alihemmati
- Department of Prosthodontics, Faculty of Dentistry, Shahed University, Tehran, Iran,Address for correspondence: Dr. Mohammad Alihemmati, Faculty of Dentistry, Shahed University, 1417755351, West Italia St., Vesal Shirazi St., Tehran, Iran. E-mail:
| | - Ali Jamali Ghomi
- Department of Prosthodontics, Faculty of Dentistry, Shahed University, Tehran, Iran
| | | | - Kamran Kargar
- Department of Prosthodontics, Faculty of Dentistry, Shahed University, Tehran, Iran
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Pereira R, Lins RBE, Rodrigues VC, Lima DANL, Martins LRM, Aguiar FHB. Glass fiber posts. BRAZILIAN JOURNAL OF ORAL SCIENCES 2020. [DOI: 10.20396/bjos.v19i0.8657508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Aim: Glass fiber posts are indicated in the rehabilitation of extensively damaged teeth; their cementation represents a critical step in restorative dentistry. The aim of this study was to quantify and compare the push-out bond strength of glass fiber posts cemented by conventional technique, two-step technique with luting agent and two-step technique associating bulk-fill composite and luting agent. Methods: Eighty maxillary bovine incisors were endodontically treated and divided into eight groups (n = 10) according to the luting agent (Rely X ARC and Duo-link) and cementation technique (conventional technique; two-step technique with luting agent; and two-step technique associating bulk-fill composite – Filtek Bulk-fill flow or Surefil SDR flow – and luting agent). Samples were submitted to pushout bond strength test, and the fracture pattern was evaluated through scanning electron microscope. Data were submitted to two-way ANOVA and Tukey’s test (α = 0.05). Results: When Rely X ARC was used, the conventional cementation technique obtained higher bond strength values than the twostep technique associated with Filtek Bulk-fill flow. When Duolink was used, the two-step technique associated with Filtek Bulk-fill flow presented higher bond strength values than the conventional technique. The most prevalent fracture patterns were adhesive between luting agent and dentin, and adhesive between bulk-fill composite and dentin. Conclusion: Two-step cementation technique associated with bulk-fill composite may be promising depending on the luting agent used.
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Hakim MAA, Khatab NMA, Mohamed KMG, Elheeny AAH. A Comparative Three-Dimensional Finite Element Study of Two Space Regainers in the Mixed Dentition Stage. Eur J Dent 2020; 14:107-114. [PMID: 32168538 PMCID: PMC7069744 DOI: 10.1055/s-0040-1702254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Objectives
This study aims to compare the stress distribution and displacement that resulted from the use of a Gerber space regainer and sagittal distalizer using three-dimensional finite element analysis.
Materials and Methods
Three-dimensional simulated models of the appliances were developed using a software. The forces applied by the two appliances were 3N (tipping) and 15N (bodily), respectively. Displacement and von Mises stress on the compact and cancellous bone, periodontal ligament (PDL), crowns of the mandibular first, second permanent molars, and deciduous canines were calculated. Stress distribution and displacement values were measured via linear static analysis.
Results
Gerber space regainer showed greater displacement than that produced by the sagittal distalizer at the first permanent molar. However, such displacement was less at the other tested points when compared with that delivered by sagittal distalizer. The stresses created by Gerber appliance were higher in the crown and PDL of the deciduous canine than the crown of the first permanent molar crown.
Conclusions
Gerber appliance generates more distal force and less stress concentration on the crown of the mandibular first permanent molar than that created by the sagittal distalizer. On the other hand, stress concentrations produced by Gerber space regainer are found to be more on the crown and PDL of the deciduous canine. Therefore, it can be concluded that the use of Gerber appliance needs more anchorage.
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Affiliation(s)
| | - Nagwa Mohamed Ali Khatab
- Department of Paediatric and Community Dentistry, Faculty of Dentistry, Minia University, Minya, El Minia, Egypt
| | | | - Ahmad Abdel Hamid Elheeny
- Department of Paediatric and Community Dentistry, Faculty of Dentistry, Minia University, Minya, El Minia, Egypt
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Correia AMDO, Tribst JPM, Matos FDS, Platt JA, Caneppele TMF, Borges ALS. Polymerization shrinkage stresses in different restorative techniques for non-carious cervical lesions. J Dent 2018; 76:68-74. [DOI: 10.1016/j.jdent.2018.06.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 06/14/2018] [Accepted: 06/19/2018] [Indexed: 10/28/2022] Open
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Richert R, Robinson P, Viguie G, Farges JC, Ducret M. Multi-Fiber-Reinforced Composites for the Coronoradicular Reconstruction of Premolar Teeth: A Finite Element Analysis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4302607. [PMID: 29984233 PMCID: PMC6011147 DOI: 10.1155/2018/4302607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/08/2018] [Indexed: 11/17/2022]
Abstract
A coronoradicular reconstruction (CRR) has conventionally used a metallic inlay core (MIC) or a single-fiber-reinforced composite (sFRC) but extensive dentin removal can lead to root fracture. We propose herein a multi-fiber-reinforced composite (mFRC) based on a bundle of thin flexible fibers that can be adapted to the root anatomy without removing additional dentin. The aim of this study was to compare the mechanical behavior of the root reconstructed with mFRC, MIC, or sFRC using a finite element analysis (FEA). Models with or without a ferrule effect were created using Autodesk© software and divided into four parts: root, post, bonding composite or cement, and zirconia crown. For both models, extreme stress values (ESV), stress distribution, and risk of fracture were calculated for an oblique force (45°) of 100 N applied to the top of the buccal cusp. Results indicated that mFRC and mFRCG present a lower risk of fracture of the root and of the CRR without ferrule and thus could be valuable alternatives for premolar CRR. Further studies are necessary to evaluate the clinical success of these CRR.
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Affiliation(s)
- Raphaël Richert
- Université de Lyon, Université Lyon 1, Faculté d'Odontologie, Lyon, France
- Hospices Civils de Lyon, Service de Consultations et Traitements Dentaires, Lyon, France
| | | | - Gilbert Viguie
- Université de Lyon, Université Lyon 1, Faculté d'Odontologie, Lyon, France
- Hospices Civils de Lyon, Service de Consultations et Traitements Dentaires, Lyon, France
| | - Jean-Christophe Farges
- Université de Lyon, Université Lyon 1, Faculté d'Odontologie, Lyon, France
- Hospices Civils de Lyon, Service de Consultations et Traitements Dentaires, Lyon, France
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMR5305 CNRS/Université Lyon 1, UMS3444 BioSciences Gerland-Lyon Sud, Lyon, France
| | - Maxime Ducret
- Université de Lyon, Université Lyon 1, Faculté d'Odontologie, Lyon, France
- Hospices Civils de Lyon, Service de Consultations et Traitements Dentaires, Lyon, France
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMR5305 CNRS/Université Lyon 1, UMS3444 BioSciences Gerland-Lyon Sud, Lyon, France
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HATAYAMA T, CHIBA A, KAINOSE K, NAKAJIMA M, HOSAKA K, WAKABAYASHI N, FOXTON RM, TAGAMI J. Stress distribution in tooth resin core build-ups with different post-end positions in alveolar bone level under two kinds of load directions. Dent Mater J 2018; 37:474-483. [DOI: 10.4012/dmj.2017-160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Takashi HATAYAMA
- Cariology and Operative Dentistry, Oral Restitution Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Ayaka CHIBA
- Cariology and Operative Dentistry, Oral Restitution Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Kimisuke KAINOSE
- Cariology and Operative Dentistry, Oral Restitution Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masatoshi NAKAJIMA
- Cariology and Operative Dentistry, Oral Restitution Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Keiichi HOSAKA
- Cariology and Operative Dentistry, Oral Restitution Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Noriyuki WAKABAYASHI
- Removable Partial Prosthodontics Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Richard M. FOXTON
- Division of Conservative Dentistry, King’s College London Dental Institute at Guy’s, King’s and St Thomas’ Hospitals, King’s College London
| | - Junji TAGAMI
- Cariology and Operative Dentistry, Oral Restitution Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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Effect of Anatomical Customization of the Fiber Post on the Bond Strength of a Self-Adhesive Resin Cement. Int J Dent 2017; 2017:5010712. [PMID: 28785281 PMCID: PMC5530420 DOI: 10.1155/2017/5010712] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/08/2017] [Indexed: 11/18/2022] Open
Abstract
AIM The aim of the study was to evaluate, by means of the push-out test, the effect of the anatomical customization of the fiber post on the bond strength of a self-adhesive resin cement. METHODS Twelve endodontically treated, human, upper central incisors were randomly divided into two groups (n = 6): control (glass fiber posts cemented with Relyx® U200) and customized (glass fiber posts anatomically customized with translucent composite resin cemented with Relyx U200). The roots were sectioned into three slices, cervical, middle, and apical, and photographed with a digital camera attached to a stereomicroscopic loupe. The images were analyzed by software, for evaluation of the cement line. The slices were subsequently submitted to the push-out test until the post had completely extruded, and the fracture mode was analyzed with a stereomicroscopic loupe. RESULTS The results showed significant differences between the groups in the different root thirds in relation to the area occupied by air bubbles (p < 0.05). Bond strength, when all the thirds are considered, was 8.77 ± 4.89 MPa for the control group and 16.96 ± 4.85 MPa for the customized group. CONCLUSION The customized group showed greater bond resistance than the control group and a more uniform cement layer.
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Mamoun J. Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages. J Adv Prosthodont 2017; 9:232-237. [PMID: 28680556 PMCID: PMC5483411 DOI: 10.4047/jap.2017.9.3.232] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 11/17/2016] [Accepted: 12/07/2016] [Indexed: 12/01/2022] Open
Abstract
Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.
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Affiliation(s)
- John Mamoun
- Sunbeam Dental - General Dentistry, Manalapan, NJ, USA
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Dal Piva AMDO, Tribst JPM, Souza RODAE, Borges ALS. Influence of Alveolar Bone Loss and Cement Layer Thickness on the Biomechanical Behavior of Endodontically Treated Maxillary Incisors: A 3-dimensional Finite Element Analysis. J Endod 2017; 43:791-795. [DOI: 10.1016/j.joen.2016.11.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/15/2016] [Accepted: 11/24/2016] [Indexed: 10/19/2022]
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Influence of remaining tooth structure and restorative material type on stress distribution in endodontically treated maxillary premolars: A finite element analysis. J Prosthet Dent 2016; 117:646-655. [PMID: 27881319 DOI: 10.1016/j.prosdent.2016.08.023] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 08/06/2016] [Accepted: 08/08/2016] [Indexed: 10/20/2022]
Abstract
STATEMENT OF PROBLEM How tooth preparation and material type affect the stress distribution of endodontically treated teeth restored with endocrowns remains unclear. PURPOSE The purpose of this finite element (FE) study was to determine the influence of the quantity of remaining dental tissues and material type on stress distribution in endodontically treated maxillary premolars using 3-dimensional FE analysis. MATERIAL AND METHODS Five 3-dimensional FE models were constructed on the basis of the restorative methods used and the quantity of preserved tooth tissues: a sound maxillary premolar, an endodontically treated maxillary premolar restored with composite resin, and endodontically treated maxillary premolars restored with endocrowns with thicknesses of 1.0 mm, 2.0 mm, and 3.0 mm. The following endocrown materials were used: Paradigm MZ100, IPS Empress, IPS e.max CAD, and In-Ceram Zirconia. Stress distributions were analyzed under vertical and oblique loads. RESULTS As the quantity of preserved dental tissues increased, the von Mises stress in dentin decreased, and the peak von Mises strain value of the cement layer increased. When the elastic modulus of the endocrown material increased, the von Mises stress in endocrown and dentin increased, and the peak von Mises strain value of the cement layer decreased. CONCLUSIONS Although the conservative preparation of teeth for endocrowns is likely to protect the residual tooth structure, it may cause future cohesive bonding failure. An increase in the elastic modulus of the material may benefit the durability of bonding between the endocrown and the abutment tooth; however, it may cause fracture of the residual tooth structure.
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