根管治疗后前磨牙用新型根管全冠系统修复的生物力学行为：三维有限元与威布尔分析。

Biomechanical behavior of endodontically treated premolar teeth restored with novel endocrown system: 3D Finite Element and Weibull analyses.

机构信息

Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Egypt.

Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Egypt; Fixed Prosthodontics Department, Faculty of Dentistry, Horus University, Egypt.

出版信息

J Mech Behav Biomed Mater. 2021 Dec;124:104853. doi: 10.1016/j.jmbbm.2021.104853. Epub 2021 Sep 23.

DOI:10.1016/j.jmbbm.2021.104853

PMID:34600429

Abstract

OBJECTIVE

To date, there is no clear consensus in the literature which endocrown design with which material is the most effective treatment option to restore endodontically treated maxillary premolars with extensive loss of tooth structure. The aim of this study was to evaluate the stress distribution pattern and failure probability of maxillary first premolars restored with a novel endocrown system compared to the conventional one by means of Finite Element and Weibull analyses.

MATERIALS AND METHODS

Two finite element (FE) models representing two endocrown systems used for restoration of severely-destructed endodontically treated maxillary first premolar tooth were generated: model C for the conventional monolithic IPS e.max CAD endocrown and model P for the novel bi-layered endocrown (PEKKTON ivory coping veneered with cemented IPS e.max CAD). A static occlusal compressive load was axially and centrally-applied. Modified von Mises and maximum principal stress values on the remaining tooth structure, cement lines and restorative materials were evaluated separately. Weibull function was incorporated with FE analysis to calculate the long term failure probability.

RESULTS

Regarding stresses occurred in the remaining tooth structure (enamel and dentin), model P transmitted less stresses than model C. The individual enamel of model C showed about 5% and 40% risk of failure at normal and maximum occlusal load values, respectively, while for model P, it had no failure risk at both values. For dentin, model C showed about 13% failure risk at the normal masticatory force, while model P showed only 2%. At clenching value, model C dentin showed about 44% failure risk, while only 9% was resulted for model P.

CONCLUSIONS

Compared to the conventional endocrown system, the positive impact of the studied novel endocrown system on the stress distribution pattern and also on the survival/failure probability of the restored severely-destructed endodontically treated maxillary first premolar teeth was reflected (more tooth-friendly), not only at normal masticatory forces but also at the maximum functional loads.

CLINICAL SIGNIFICANCE

The novel endocrown system using a PEKK coping veneered with cemented IPS e.max CAD can be considered a favorable option for restoration of severely-destructed endodontically treated premolar teeth, with more protection for residual tooth structure. Despite the conventional endocrown system may benefit the durability of tooth bonding, it should not be selected for restoration of clenching cases because of the too high overall failure risk.

摘要

目的

迄今为止，文献中尚无明确共识，即哪种 endocrown 设计与哪种材料是修复广泛牙体结构丧失的根管治疗上颌前磨牙最有效的治疗选择。本研究的目的是通过有限元分析和威布尔分析来评估新型 endocrown 系统修复上颌第一前磨牙的应力分布模式和失效概率，并与传统系统进行比较。

材料和方法

生成了两种代表两种用于修复严重破坏的根管治疗上颌第一前磨牙的 endocrown 系统的有限元（FE）模型：模型 C 用于传统的整体式 Ips e.max CAD endocrown，模型 P 用于新型的双层 endocrown（PEKKTON 象牙覆盖层，用粘结 Ips e.max CAD 贴面）。轴向和中央施加静态的咬合压缩载荷。分别评估剩余牙体结构、粘结线和修复材料上的修正的 von Mises 和最大主应力值。威布尔函数与 FE 分析相结合，以计算长期失效概率。

结果

关于剩余牙体结构（牙釉质和牙本质）中发生的应力，模型 P 传递的应力小于模型 C。模型 C 的个体牙釉质在正常和最大咬合载荷值下分别有 5%和 40%的失效风险，而模型 P 在这两个值下均无失效风险。对于牙本质，模型 C 在正常咀嚼力下有 13%的失效风险，而模型 P 只有 2%。在咬牙合值时，模型 C 牙本质的失效风险约为 44%，而模型 P 仅为 9%。