Altamimi Mohamed Gomaa, Mahallawi Omaima El, Lukomska-Szymanska Monika, Turky Mohammed
Department of Fixed Prosthodontics, Faculty of Dentistry, Minia University, Minia, Egypt.
Ministry of Health and Population, Kafr El Sheikh, Desouk, Egypt.
BMC Oral Health. 2025 Jul 19;25(1):1214. doi: 10.1186/s12903-025-06586-y.
Root canal-treated teeth often exhibit significant structural loss, necessitating effective and conservative restorative techniques. The present study aimed to assess the effect of cavity design on the fracture resistance of endo-crown restorations.
Thirty human mandibular first molars were carefully chosen based on a sample size estimation. All teeth underwent root canal treatment and were allocated into three groups (n = 10 each) according to the cavity design; conventional cavity design (group 1), conventional cavity design with a root canal extension (group 2), and conventional cavity design with a buccal groove (group 3). Following cementation of the endo-crown restorations and submission to thermo-mechanical fatigue, each group was subjected to fracture resistance testing and failure mode analysis. A one-way ANOVA and Tukey's post hoc tests were conducted to compare the mean fracture load values, while the Chi-square test was used to compare failure modes among the study groups. The significance was set at 5% with a confidence interval (CI) of 95%.
The conventional design demonstrated the highest fracture resistance, significantly outperforming the other designs (P < 0.0001). The root canal extension design showed the lowest resistance, while the buccal groove design exhibited intermediate results (P < 0.0001). Failure mode analysis revealed distinct patterns, indicating that the conventional design with root canal extension fractured under the lowest loads, yielded the most favorable outcomes (P < 0.0001).
The choice of cavity design significantly impacts the mechanical performance of endo-crown restorations. Endo-crown restorations exhibited the highest fracture resistance in the conventional cavity design. Moreover, the design extending into a buccal groove can be preferred over the extension into the root canals.
The findings support using conventional designs to boost the longevity and effectiveness of restorations in root canal-treated teeth. When additional extensions are required, a buccal groove extension is suggested rather than an extension into the root canal. This study contributes valuable insights for clinicians in selecting optimal restorative strategies for root canal-treated teeth.
Non-applicable. Conducting the current experiment was limited to the approval by the local Research Ethics Committee at the Faculty of Dentistry, Minia University, Egypt (committee no. 94, registration no. 705, dated 28 February 2023).
根管治疗后的牙齿通常会出现明显的结构缺损，因此需要有效且保守的修复技术。本研究旨在评估洞型设计对内冠修复体抗折性能的影响。
根据样本量估算精心挑选30颗人类下颌第一磨牙。所有牙齿均接受根管治疗，并根据洞型设计分为三组（每组n = 10）；传统洞型设计（第1组）、带有根管延伸的传统洞型设计（第2组）和带有颊沟的传统洞型设计（第3组）。在内冠修复体粘结并进行热机械疲劳试验后，对每组进行抗折性能测试和失败模式分析。采用单因素方差分析和Tukey事后检验比较平均抗折载荷值，同时采用卡方检验比较各研究组之间的失败模式。显著性设定为5%，置信区间（CI）为95%。
传统设计表现出最高的抗折性能，显著优于其他设计（P < 0.0001）。根管延伸设计的抗折性能最低，而颊沟设计的结果居中（P < 0.0001）。失败模式分析显示出不同的模式，表明带有根管延伸的传统设计在最低载荷下发生折断，产生了最有利的结果（P < 0.0001）。
洞型设计的选择显著影响内冠修复体的力学性能。传统洞型设计的内冠修复体表现出最高的抗折性能。此外，延伸至颊沟的设计可能比延伸至根管更可取。
研究结果支持使用传统设计来提高根管治疗后牙齿修复体的使用寿命和有效性。当需要额外延伸时，建议采用颊沟延伸而非根管延伸。本研究为临床医生选择根管治疗后牙齿的最佳修复策略提供了有价值的见解。
不适用。进行当前实验仅限于获得埃及米尼亚大学牙科学院当地研究伦理委员会的批准（委员会编号94，注册号705，日期为2023年2月28日）。
