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Chai H. Edge chipping patterns in posterior teeth of hominins and apes. J Mech Behav Biomed Mater 2024; 156:106582. [PMID: 38781774 DOI: 10.1016/j.jmbbm.2024.106582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/11/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024]
Abstract
Chip scars in fossil teeth are a lasting evidence that bears on human evolution. Chip dimensions in posterior teeth of hominins, apes and white-lipped peccary (Tayassu pecari) are measured from published occlusal images. The results are plotted as D/Dm vs. h/Dm, where h, D and Dm denote indent distance, chip width and mean tooth crown diameter. The hominin species follow a similar pattern where D/Dm monotonically increases up to h/Dm ≈ 0.3. The behavior for the apes is characterized by two phases. In the first, h/Dm monotonically increases up to h/Dm ≈ 0.26 while in the second (h/Dm ≈ 0.26 to 0.42), D/Dm experiences a drastic change in behavior. The interpretation of chip morphology is assisted by results from controlled spherical indentation tests on extracted human molars. This study shows that in addition to the commonly recognized chipping due to cusp loading, a chip may also initiate from the inner wall of the tooth's central fossa. Accordingly, it is suggested that the chipping in hominins generally initiates from a (worn) cusp while that in apes involves cusp loading up to h/Dm ≈ 0.26 and fossa loading thereafter. The behavior for T. pecari is much similar to that of the apes. The fossa chipping is facilitated by a consumption of hard, large-size diet (e.g., plants, roots, barks and nuts) and presence of broad central fossa, conditions that are met in apes. Finally, a simple expression for the critical chipping force Pch due to fossa loading is developed.
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Affiliation(s)
- Herzl Chai
- School of Mechanical Engineering, Tel-Aviv University, Tel-Aviv, Israel.
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2
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Broll A, Goldhacker M, Hahnel S, Rosentritt M. Generative deep learning approaches for the design of dental restorations: A narrative review. J Dent 2024; 145:104988. [PMID: 38608832 DOI: 10.1016/j.jdent.2024.104988] [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: 01/23/2024] [Revised: 03/13/2024] [Accepted: 04/03/2024] [Indexed: 04/14/2024] Open
Abstract
OBJECTIVES This study aims to explore and discuss recent advancements in tooth reconstruction utilizing deep learning (DL) techniques. A review on new DL methodologies in partial and full tooth reconstruction is conducted. DATA/SOURCES PubMed, Google Scholar, and IEEE Xplore databases were searched for articles from 2003 to 2023. STUDY SELECTION The review includes 9 articles published from 2018 to 2023. The selected articles showcase novel DL approaches for tooth reconstruction, while those concentrating solely on the application or review of DL methods are excluded. The review shows that data is acquired via intraoral scans or laboratory scans of dental plaster models. Common data representations are depth maps, point clouds, and voxelized point clouds. Reconstructions focus on single teeth, using data from adjacent teeth or the entire jaw. Some articles include antagonist teeth data and features like occlusal grooves and gap distance. Primary network architectures include Generative Adversarial Networks (GANs) and Transformers. Compared to conventional digital methods, DL-based tooth reconstruction reports error rates approximately two times lower. CONCLUSIONS Generative DL models analyze dental datasets to reconstruct missing teeth by extracting insights into patterns and structures. Through specialized application, these models reconstruct morphologically and functionally sound dental structures, leveraging information from the existing teeth. The reported advancements facilitate the feasibility of DL-based dental crown reconstruction. Beyond GANs and Transformers with point clouds or voxels, recent studies indicate promising outcomes with diffusion-based architectures and innovative data representations like wavelets for 3D shape completion and inference problems. CLINICAL SIGNIFICANCE Generative network architectures employed in the analysis and reconstruction of dental structures demonstrate notable proficiency. The enhanced accuracy and efficiency of DL-based frameworks hold the potential to enhance clinical outcomes and increase patient satisfaction. The reduced reconstruction times and diminished requirement for manual intervention may lead to cost savings and improved accessibility of dental services.
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Affiliation(s)
- Alexander Broll
- Department of Prosthetic Dentistry, University Hospital Regensburg, Regensburg, Germany
| | - Markus Goldhacker
- Faculty of Mechanical Engineering, OTH Regensburg, Regensburg, Germany
| | - Sebastian Hahnel
- Department of Prosthetic Dentistry, University Hospital Regensburg, Regensburg, Germany
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, University Hospital Regensburg, Regensburg, Germany
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Broll A, Rosentritt M, Schlegl T, Goldhacker M. A data-driven approach for the partial reconstruction of individual human molar teeth using generative deep learning. Front Artif Intell 2024; 7:1339193. [PMID: 38690195 PMCID: PMC11058210 DOI: 10.3389/frai.2024.1339193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 03/19/2024] [Indexed: 05/02/2024] Open
Abstract
Background and objective Due to the high prevalence of dental caries, fixed dental restorations are regularly required to restore compromised teeth or replace missing teeth while retaining function and aesthetic appearance. The fabrication of dental restorations, however, remains challenging due to the complexity of the human masticatory system as well as the unique morphology of each individual dentition. Adaptation and reworking are frequently required during the insertion of fixed dental prostheses (FDPs), which increase cost and treatment time. This article proposes a data-driven approach for the partial reconstruction of occlusal surfaces based on a data set that comprises 92 3D mesh files of full dental crown restorations. Methods A Generative Adversarial Network (GAN) is considered for the given task in view of its ability to represent extensive data sets in an unsupervised manner with a wide variety of applications. Having demonstrated good capabilities in terms of image quality and training stability, StyleGAN-2 has been chosen as the main network for generating the occlusal surfaces. A 2D projection method is proposed in order to generate 2D representations of the provided 3D tooth data set for integration with the StyleGAN architecture. The reconstruction capabilities of the trained network are demonstrated by means of 4 common inlay types using a Bayesian Image Reconstruction method. This involves pre-processing the data in order to extract the necessary information of the tooth preparations required for the used method as well as the modification of the initial reconstruction loss. Results The reconstruction process yields satisfactory visual and quantitative results for all preparations with a root mean square error (RMSE) ranging from 0.02 mm to 0.18 mm. When compared against a clinical procedure for CAD inlay fabrication, the group of dentists preferred the GAN-based restorations for 3 of the total 4 inlay geometries. Conclusions This article shows the effectiveness of the StyleGAN architecture with a downstream optimization process for the reconstruction of 4 different inlay geometries. The independence of the reconstruction process and the initial training of the GAN enables the application of the method for arbitrary inlay geometries without time-consuming retraining of the GAN.
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Affiliation(s)
- Alexander Broll
- Department of Prosthetic Dentistry, University Hospital Regensburg, Regensburg, Germany
- Faculty of Mechanical Engineering, Ostbayerische Technische Hochschule Regensburg, Regensburg, Germany
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, University Hospital Regensburg, Regensburg, Germany
| | - Thomas Schlegl
- Faculty of Mechanical Engineering, Ostbayerische Technische Hochschule Regensburg, Regensburg, Germany
| | - Markus Goldhacker
- Faculty of Mechanical Engineering, Ostbayerische Technische Hochschule Regensburg, Regensburg, Germany
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Gierthmuehlen PC, Spitznagel FA, Koschate M, Bonfante EA, Prott LS. Influence of ceramic thickness and dental substrate on the survival rate and failure load of non-retentive occlusal veneers after fatigue. J ESTHET RESTOR DENT 2024; 36:373-380. [PMID: 37605963 DOI: 10.1111/jerd.13103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 04/26/2023] [Accepted: 06/27/2023] [Indexed: 08/23/2023]
Abstract
OBJECTIVE To investigate the effect of ceramic thickness and dental substrate (enamel vs. dentin/enamel) on the survival rate and failure load of non-retentive occlusal veneers. MATERIALS AND METHODS Human maxillary molars (n = 60) were divided into five test-groups (n = 12). The groups (named DE-1.5, DE-1.0, DE-0.5, E-1.0, E-0.5) differed in their dental substrate (E = enamel, DE = dentin/enamel) and restoration thickness (standard: 1.5 mm, thin: 1.0 mm, ultrathin: 0.5 mm). All teeth were prepared for non-retentive monolithic lithium-disilicate occlusal veneers (IPS e.max Press, Ivoclar). Restorations were adhesively cemented (Syntac Classic/Variolink II, Ivoclar) and exposed to thermomechanical fatigue (1.2 million cycles, 1.6 Hz, 49 N/ 5-55°C). Single load to failure was performed using a universal testing-machine. A linear-regression model was applied, pairwise comparisons used the Student-Newman-Keuls method (p < 0.05). RESULTS Three dentin-based occlusal veneers (one DE-1.0, two DE-0.5) revealed cracks after fatigue exposure, which corresponds to an overall-survival rate of 95%. Load to failure resulted in the following ranking: 2142 N(DE-0.5) > 2105 N(E-1.0) > 2075 N(E-0.5) > 1440 N(DE-1.5) > 1430 N(DE-1.0). Thin (E-1.0) and ultrathin enamel-based occlusal veneers (E-0.5) revealed high failure loads and surpassed the standard thickness dentin-based veneers (DE-1.5) significantly (p = 0.044, p = 0.022). CONCLUSION All tested monolithic lithium disilicate occlusal veneers obtained failure loads above physiological chewing forces. Thin and ultrathin enamel-based occlusal veneers outperformed the standard thick dentin-based occlusal veneers. CLINICAL SIGNIFICANCE Minimally invasive enamel-based occlusal veneer restorations with non-retentive preparation design may serve as a conservative treatment option.
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Affiliation(s)
- Petra C Gierthmuehlen
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - Frank A Spitznagel
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | | | - Estevam A Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, SP, Brazil
| | - Lea S Prott
- Department of Prosthodontics, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
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Chai H. On edge chipping in molar teeth from blunt occlusal contact. J Mech Behav Biomed Mater 2023; 148:106206. [PMID: 37944225 DOI: 10.1016/j.jmbbm.2023.106206] [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: 09/20/2023] [Revised: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023]
Abstract
Edge chipping is a leading failure mode in dental teeth. Virtually all chipping studies are limited to Vickers indentation on polished cusps of molar teeth. Such works are here extended to spherical contact. Occlusal loads are applied on the tooth's central fossa or a polished cusp using ball radii ranging from 0.4 to 5.16 mm. The chip dimensions are characterized by h/Dm and D/Dm, where h, D and Dm denote indent distance, chip size and tooth crown diameter. For the fossa loading, h/Dm, D/Dm and the least chipping force Pch are virtually independent of ball radius r for r < ≈ 4 mm. In this range, h/Dm and D/Dm lie between ≈0.30 to 0.36 and 0.51 to 0.69, respectively, while Pch equals ≈1330 N. For r > ≈ 4 mm, the failure occurs by debonding of enamel sectors from the dentin core. In the case of cusp loading, h/Dm < ≈ 0.3 while D/Dm and Pch vary with r. For relatively small h or large r, the failure occurs as soon as radial cracks initiate under the loading point. For a load applied near a cusp tip, the failure occurs by enamel debonding. Finally, the present work is easily extendable to fossil teeth of hominins and apes as well as prosthetic teeth. The morphological features obtained in such studies should provide quantitative means to assess the relationships between chip dimensions, chipping force and diet characteristics.
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Affiliation(s)
- Herzl Chai
- School of Mechanical Engineering, Tel-Aviv University, Tel-Aviv, Israel.
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Strasser T, Wertz M, Koenig A, Koetzsch T, Rosentritt M. Microstructure, composition, and flexural strength of different layers within zirconia materials with strength gradient. Dent Mater 2023; 39:463-468. [PMID: 36907821 DOI: 10.1016/j.dental.2023.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 02/01/2023] [Accepted: 03/03/2023] [Indexed: 03/12/2023]
Abstract
OBJECTIVES The aim of this study was to compare composition, microstructure, and mechanical strength of current multilayer zirconia blanks. METHODS Bar shaped specimens were made from several layers of multilayer zirconia blanks (Cercon ht ML, Dentsply Sirona, US; Katana Zirconia YML, Kuraray, J;SHOFU Disk ZR Lucent Supra, Shofu, J; priti multidisc ZrO2 Multi Translucent, Pritidenta, D; IPS e.max ZirCAD Prime, Ivoclar Vivadent, FL). Flexural strength was determined in a three-point bending test on extra-thin bars. X-ray diffraction (XRD) with Rietveld refinement was used to assess crystal structure and scanning electron microscopy (SEM) imaging to visualize the microstructure of each material and layer. RESULTS Mean flexural strength varied between 467.5 ± 97.5 MPa (top layer, IPS e.max ZirCAD Prime) and 898.0 ± 188.5 MPa (bottom layer, Cercon ht ML) with significant (p ≤ 0.055) differences between the individual layers. XRD indicated 5Y-TZP for enamel-layers, 3Y-TZP for dentine-layers, individual mixtures of 3Y-TZP, 4Y-TZP, or 5 Y-TZP for intermediate layers. SEM analysis showed grain sizes between approx. 0.15 and 4 µm. Grain size tended to decrease from top to bottom layers. SIGNIFICANCE The investigated blanks differ predominantly in the intermediate layers. In addition to dimensioning of restorations, the milling position in the blanks must also be taken into account when using multilayer zirconia as restorative material.
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Affiliation(s)
- Thomas Strasser
- Department of Prosthetic Dentistry, University Hospital of Regensburg, 93053 Regensburg, Germany.
| | - Markus Wertz
- Department of Prosthodontics and Material Sciences, Leipzig University, 04103 Leipzig, Germany
| | - Andreas Koenig
- Department of Prosthodontics and Material Sciences, Leipzig University, 04103 Leipzig, Germany
| | - Torsten Koetzsch
- Institute of Mineralogy, Crystallography and Materials Science, Leipzig University, 04275 Leipzig, Germany
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, University Hospital of Regensburg, 93053 Regensburg, Germany
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Shelar P, Abdolvand H, Butler S. On the behaviour of zirconia-based dental materials: A review. J Mech Behav Biomed Mater 2021; 124:104861. [PMID: 34600431 DOI: 10.1016/j.jmbbm.2021.104861] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 11/28/2022]
Abstract
Zirconia-based dental materials are extensively used in clinical practice due to their tooth-like appearance, biofunctionality, biocompatibility, and affordability. However, premature clinical failures of veneering porcelains raise a concern about their integrity. Extensive studies have been performed over a decade to resolve this issue, but it is challenging to reference all information effectively. A single source identifying the significance of potential parameters on material performance has not previously been available. An evidence-based meta-narrative review technique was used to review the characteristic parameters that can affect the overall behaviour of zirconia-based materials. Keywords were chosen to assess manuscripts based on scientific coherence with this paper's research objective. Online keyword searches were carried out on ScienceDirect, PubMed, and SAGE databases for relevant published manuscripts from year 1985-2020.261 out of 3170 identified manuscripts were included. A total of 10 parameters were identified and classified into the material, manufacturing, and geometric aspects. The effect of every parameter was reviewed on the performance of the material. A discrepancy in findings was observed and is attributed to the fact that there is no standard methodology. This review acts as a single source that summarizes various parameters' contribution to zirconia-based dental materials' performance. This review facilitates manufacturing improvements by accounting for every parameter's effect on overall performance.
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Affiliation(s)
- Prashant Shelar
- Department of Mechanical & Materials Engineering, Western University, London, Ontario, Canada
| | - Hamidreza Abdolvand
- Department of Mechanical & Materials Engineering, Western University, London, Ontario, Canada
| | - Sheila Butler
- Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
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Rosentritt M, Preis V, Behr M, Strasser T. Fatigue and wear behaviour of zirconia materials. J Mech Behav Biomed Mater 2020; 110:103970. [DOI: 10.1016/j.jmbbm.2020.103970] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 01/10/2023]
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Shahmoradi M, Wan B, Zhang Z, Wilson T, Swain M, Li Q. Monolithic crowns fracture analysis: The effect of material properties, cusp angle and crown thickness. Dent Mater 2020; 36:1038-1051. [DOI: 10.1016/j.dental.2020.04.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 04/18/2020] [Accepted: 04/30/2020] [Indexed: 11/29/2022]
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Xinggang L, Xiaoxian C. [Reliability study in the measurement of the cusp inclination angle of a chairside digital model]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2018; 36:56-59. [PMID: 29594997 DOI: 10.7518/hxkq.2018.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE This study aims to evaluate the reliability of the software Picpick in the measurement of the cusp inclination angle of a digital model. METHODS Twenty-one trimmed models were used as experimental objects. The chairside digital impression was then used for the acquisition of 3D digital models, and the software Picpick was employed for the measurement of the cusp inclination of these models. The measurements were repeated three times, and the results were compared with a gold standard, which was a manually measured experimental model cusp angle. The intraclass correlation coefficient (ICC) was calculated. RESULTS The paired t test value of the two measurement methods was 0.91. The ICCs between the two measurement methods and three repeated measurements were greater than 0.9. The digital model achieved a smaller coefficient of variation (9.9%). CONCLUSIONS The software Picpick is reliable in measuring the cusp inclination of a digital model.
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Affiliation(s)
- Liu Xinggang
- Dept. of Prosthodontics, Beijing Stomatological Hospital, Capital Medical University, Beijing 100050, China
| | - Chen Xiaoxian
- First Dental Center, Peking University Hospital of Stomatology, Beijing 100034, China
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Al-Akhali M, Chaar MS, Elsayed A, Samran A, Kern M. Fracture resistance of ceramic and polymer-based occlusal veneer restorations. J Mech Behav Biomed Mater 2017. [DOI: 10.1016/j.jmbbm.2017.06.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Elshiyab SH, Nawafleh N, George R. Survival and testing parameters of zirconia-based crowns under cyclic loading in an aqueous environment: A systematic review. ACTA ACUST UNITED AC 2017; 8. [DOI: 10.1111/jicd.12261] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 01/07/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Shareen Hayel Elshiyab
- School of Dentistry and Oral Health; Griffith University; Gold Coast Qld Australia
- Faculty of Applied Medical Sciences; Jordan University of Science and Technology; Irbid Jordan
| | - Noor Nawafleh
- School of Dentistry and Oral Health; Griffith University; Gold Coast Qld Australia
- Faculty of Applied Medical Sciences; Jordan University of Science and Technology; Irbid Jordan
| | - Roy George
- School of Dentistry and Oral Health; Griffith University; Gold Coast Qld Australia
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Rocha CODM, Longhini D, Pereira RDP, Arioli JN. Influence of Cusp Inclination and Type of Retention on Fracture Load of Implant-Supported Crowns. Braz Dent J 2017; 28:92-96. [PMID: 28301025 DOI: 10.1590/0103-6440201701342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 11/25/2016] [Indexed: 11/22/2022] Open
Abstract
There are few informations about the influence of cusp inclination on the fracture strength of implant-supported crowns. The study aimed to evaluate the influence of cusp inclination and retention type on fracture load in implant-supported metal-ceramic single crowns. Sixty crowns were made, classified as cemented and screw-retained with screw access hole (SAH) sealed or not. Standard (33°) and reduced (20°) cusp inclinations were tested for each group (n=10). To support crowns of a mandibular second molar, analogs of external hexagon implants 5.0 were used. The fracture load was measured in a universal testing machine EMIC DL2000 (10 kN load cell; 0.5 mm/min). Two-way ANOVA (retention and cusp inclination) followed by post hoc Tukey's honest significant difference test was used for the statistical analyses (a=0.05). Crowns with reduced cusp inclination exhibited significantly higher fracture load (p<0.01) than crowns with standard cusp inclination. Cemented crowns showed significantly higher fracture load (p<0.01) than screw-retained crowns. The interaction among these factors was not significant (p>0.05) for the fracture load. The sealing of SAH did not influence the fracture load of screw-retained crowns (p>0.05). In conclusion, fracture load of implant-supported metal-ceramic crowns was influenced by retention and cusp inclination, and there was no influence of the sealing of SAH.
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Affiliation(s)
- Cibele Oliveira de Melo Rocha
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - Universidade Estadual Paulista, Araraquara, SP, Brazil
| | - Diogo Longhini
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - Universidade Estadual Paulista, Araraquara, SP, Brazil
| | - Rodrigo de Paula Pereira
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - Universidade Estadual Paulista, Araraquara, SP, Brazil
| | - João Neudenir Arioli
- Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - Universidade Estadual Paulista, Araraquara, SP, Brazil
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Guo J, Li D, Wang H, Yang Y, Wang L, Guan D, Qiu Y, He L, Zhang S. Effect of contact stress on the cycle-dependent wear behavior of ceramic restoration. J Mech Behav Biomed Mater 2017; 68:16-25. [PMID: 28135638 DOI: 10.1016/j.jmbbm.2017.01.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/14/2017] [Accepted: 01/20/2017] [Indexed: 11/18/2022]
Abstract
AIM Ceramic restoration experiences the non-linear wear process during the chewing simulation, which contains running-in, steady and severe wear stages. However since various levels of contact stress may be applied on the occlusal surface during chewing, the cycle-dependent wear behaviors of ceramic crowns may differ. The aim of this study was to investigate the effect of contact stress on the development of wear behavior, as tested in a chewing simulator. MATERIALS AND METHODS Thirty-six anatomical metal-ceramic crowns using Ceramco III as the veneering porcelain were randomly assigned to two groups based on the contact stress applied in the wear testing. Stainless steel balls served as antagonists. The specimens were dynamically loaded in a chewing simulator up to 2.4×106 loading cycles, with additional thermal cycling between 5 and 55℃. For each group, several checkpoints were employed to measure the substance loss of the crowns' occlusal surfaces and to evaluate the microstructure of the worn areas. RESULTS After 2.4×106 cycles, the ceramic restorations with lower contact stress demonstrated a long steady wear stage following the running-in, but without the severe wear stage. And a slowly microstructural degradation was observed that the subsurface defect could not be seen until final. With higher contact stress, however, the ceramic restorations experienced a faster transition from running-in to severe wear stage that the steady wear stage nearly disappeared. And an early formation of subsurface defects and the deterioration of microstructure were observed. CONCLUSIONS Contact stress is a key factor affecting the wear development of ceramic restoration. The higher contact stress promotes the veneering porcelain to evolve into severe wear stage. In contrast, lower contact stress is prone to keep the veneering porcelain operating in steady wear stage, which delays the arrival of severe wear region.
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Affiliation(s)
- Jiawen Guo
- Department of Stomatology, Lanzhou General Hospital, Lanzhou Command of PLA, Lanzhou, Gansu, China
| | - Ding Li
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, China
| | - Haijing Wang
- Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Sai Ying Pun, Hong Kong
| | - Yanwei Yang
- Department of Stomatology, Lanzhou General Hospital, Lanzhou Command of PLA, Lanzhou, Gansu, China
| | - Liying Wang
- Department of Stomatology, Lanzhou General Hospital, Lanzhou Command of PLA, Lanzhou, Gansu, China
| | - Delin Guan
- Department of Stomatology, Lanzhou General Hospital, Lanzhou Command of PLA, Lanzhou, Gansu, China
| | - Yinong Qiu
- Department of Stomatology, Lanzhou General Hospital, Lanzhou Command of PLA, Lanzhou, Gansu, China
| | - Lin He
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, China.
| | - Shaofeng Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
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Rosentritt M, Heidtkamp F, Hösl H, Hahnel S, Preis V. In vitro comparison of implant- versus gingiva-supported removable dentures in anterior and posterior applications. Clin Oral Investig 2016; 20:275-81. [DOI: 10.1007/s00784-015-1502-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
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Kanat-Ertürk B, Çömlekoğlu EM, Dündar-Çömlekoğlu M, Özcan M, Güngör MA. Effect of Veneering Methods on Zirconia Framework-Veneer Ceramic Adhesion and Fracture Resistance of Single Crowns. J Prosthodont 2014; 24:620-8. [DOI: 10.1111/jopr.12236] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Burcu Kanat-Ertürk
- Department of Prosthodontics; Kocaeli University School of Dentistry; Kocaeli Turkey
| | - Erhan M. Çömlekoğlu
- School of Dentistry, Department of Prosthodontics; Ege University; Izmir Turkey
| | | | - Mutlu Özcan
- Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science; University of Zurich; Zurich Switzerland
| | - Mehmet Ali Güngör
- School of Dentistry, Department of Prosthodontics; Ege University; Izmir Turkey
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