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Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar

BACKGROUND: The purpose of this study was to investigate the fracture strength and stress distribution of four ceramic restorations. METHODS: Forty human mandibular first molars were collected and randomized into four groups after establishing the distal defect: full crown group with 4 mm axial wall...

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Autores principales: Luo, Bin, Sun, Xiaolu, He, Lin, Zhao, Lidan, Liu, Xinggang, Jiang, Qingsong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9714140/
https://www.ncbi.nlm.nih.gov/pubmed/36456942
http://dx.doi.org/10.1186/s12903-022-02577-5
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author Luo, Bin
Sun, Xiaolu
He, Lin
Zhao, Lidan
Liu, Xinggang
Jiang, Qingsong
author_facet Luo, Bin
Sun, Xiaolu
He, Lin
Zhao, Lidan
Liu, Xinggang
Jiang, Qingsong
author_sort Luo, Bin
collection PubMed
description BACKGROUND: The purpose of this study was to investigate the fracture strength and stress distribution of four ceramic restorations. METHODS: Forty human mandibular first molars were collected and randomized into four groups after establishing the distal defect: full crown group with 4 mm axial wall height (AWH) (FC4); short AWH crown group with 2 mm AWH (SC2); occlusal veneer group with 0 mm AWH (OV0); occlusal distal veneer group with only the distal surface prepared, and 4 mm AWH (OD4). The teeth were prepared according to the groups and the ceramic restorations were completed using celtra duo ceramic blocks. The ceramic thickness of the occlusal surface is about 1.5 mm and the edge is about 1 mm. The failure load values and fracture modes of each group were detected by mechanical test in vitro. According to the groups to establish three-dimensional finite element analysis (FEA) models, a 600 N loading force was applied vertically using a hemispherical indenter with a diameter of 6 mm. and compare the stress distribution under the condition of different restorations. RESULTS: In vitro mechanical tests showed that the failure load values were SC2 (3232.80 ± 708.12 N) > OD4 (2886.90 ± 338.72 N) > VO0 (2133.20 ± 376.15 N) > FC4(1635.40 ± 413.05 N). The failure load values of the short AWH crown and occlusal distal veneer were significantly higher than that of occlusal veneer and full crown (P<0.05). The fracture modes of the full crown and occlusal veneer groups were mainly ceramic fractures and some were restorable tooth fractures. The short AWH crown and occlusal distal veneer groups presented with three fracture modes, the proportion of non-restorable tooth fracture was higher. The results of FEA show that under the spherical loading condition, the stress of ceramic was concentrated in the contact area of the loading head, the maximum von Mises stress values were FC4 (356.2 MPa) > VO0 (214.3 MPa) > OD4 (197.9 MPa) > SC2 (163.1 MPa). The stress of enamel was concentrated in the area where the remaining enamel was thinner, the maximum von Mises stress values was OD4 (246.2 MPa) ≈ FC4 (212.4 MPa) > VO0 (61.8 MPa) ≈ SC2 (45.81 MPa). The stress of dentin is concentrated in the root furcation and the upper third region of the root. However, stress concentration was observed at the tooth cervix in the full crown. CONCLUSION: Under certain conditions, the occlusal distal veneer shows better performance than the full crown.
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spelling pubmed-97141402022-12-02 Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar Luo, Bin Sun, Xiaolu He, Lin Zhao, Lidan Liu, Xinggang Jiang, Qingsong BMC Oral Health Research BACKGROUND: The purpose of this study was to investigate the fracture strength and stress distribution of four ceramic restorations. METHODS: Forty human mandibular first molars were collected and randomized into four groups after establishing the distal defect: full crown group with 4 mm axial wall height (AWH) (FC4); short AWH crown group with 2 mm AWH (SC2); occlusal veneer group with 0 mm AWH (OV0); occlusal distal veneer group with only the distal surface prepared, and 4 mm AWH (OD4). The teeth were prepared according to the groups and the ceramic restorations were completed using celtra duo ceramic blocks. The ceramic thickness of the occlusal surface is about 1.5 mm and the edge is about 1 mm. The failure load values and fracture modes of each group were detected by mechanical test in vitro. According to the groups to establish three-dimensional finite element analysis (FEA) models, a 600 N loading force was applied vertically using a hemispherical indenter with a diameter of 6 mm. and compare the stress distribution under the condition of different restorations. RESULTS: In vitro mechanical tests showed that the failure load values were SC2 (3232.80 ± 708.12 N) > OD4 (2886.90 ± 338.72 N) > VO0 (2133.20 ± 376.15 N) > FC4(1635.40 ± 413.05 N). The failure load values of the short AWH crown and occlusal distal veneer were significantly higher than that of occlusal veneer and full crown (P<0.05). The fracture modes of the full crown and occlusal veneer groups were mainly ceramic fractures and some were restorable tooth fractures. The short AWH crown and occlusal distal veneer groups presented with three fracture modes, the proportion of non-restorable tooth fracture was higher. The results of FEA show that under the spherical loading condition, the stress of ceramic was concentrated in the contact area of the loading head, the maximum von Mises stress values were FC4 (356.2 MPa) > VO0 (214.3 MPa) > OD4 (197.9 MPa) > SC2 (163.1 MPa). The stress of enamel was concentrated in the area where the remaining enamel was thinner, the maximum von Mises stress values was OD4 (246.2 MPa) ≈ FC4 (212.4 MPa) > VO0 (61.8 MPa) ≈ SC2 (45.81 MPa). The stress of dentin is concentrated in the root furcation and the upper third region of the root. However, stress concentration was observed at the tooth cervix in the full crown. CONCLUSION: Under certain conditions, the occlusal distal veneer shows better performance than the full crown. BioMed Central 2022-12-01 /pmc/articles/PMC9714140/ /pubmed/36456942 http://dx.doi.org/10.1186/s12903-022-02577-5 Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research
Luo, Bin
Sun, Xiaolu
He, Lin
Zhao, Lidan
Liu, Xinggang
Jiang, Qingsong
Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar
title Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar
title_full Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar
title_fullStr Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar
title_full_unstemmed Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar
title_short Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar
title_sort impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9714140/
https://www.ncbi.nlm.nih.gov/pubmed/36456942
http://dx.doi.org/10.1186/s12903-022-02577-5
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