Mondelli José, Rizzante Fabio Antonio Piola, Valera Fabiano Bassalobre, Roperto Renato, Mondelli Rafael Francisco Lia, Furuse Adilson Yoshio
Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Dentística, Endodontia e Materiais Odontológicos, Bauru, São Paulo, Brasil.
Case Western Reserve University, School of Dental Medicine, Cleveland, Ohio, United States of America.
J Appl Oral Sci. 2019 Aug 12;27:e20180631. doi: 10.1590/1678-7757-2018-0631.
Extensive restorations in posterior teeth always bring doubts to the clinicians regarding the best protocol, mainly when structures of reinforcement were lost.
This study aimed to evaluate the effect of beveling on the fracture resistance and pattern of class II (MOD) restored teeth.
Ninety human premolars were randomly assigned into 9 groups: CTR (control/sound); NC (cavity preparation, non-restored); RU (restored, unbeveled); RTB (restored, entire angle beveling); RPB (restored, partial/occlusal beveling); EC (endodontic access/EA, non-restored); EU (EA, unbeveled); ETB (EA, entire angle beveling); EPB (EA, partial/occlusal beveling). Teeth were restored with Esthet X resin composite and stored in distilled water for 24 h before the inclusion in PVC cylinders. The axial loading tests were performed with 500 kgF at 0.5 mm/min crosshead speed until fracture of the specimens. Fracture resistance and pattern were accessed and data were analyzed using one-way ANOVA and Tukey's HSD test (α=0.05).
Mean (±SD) failure loads ranged from 136.56 (11.62) to 174.04 (43.5) kgF in the groups tested without endodontic access. For endodontically accessed teeth, fracture resistance ranged from 95.54 (13.05) to 126.51 (19.88) kgF. Beveling of the cavosurface angle promoted the highest fracture resistance values (p<0.05) and prevented catastrophic fractures.
Cavosurface angle beveling is capable of improving fracture resistance and pattern for both endodonticaly accessed and non-accessed teeth.
后牙的大面积修复总是让临床医生对最佳方案心存疑虑，尤其是在失去增强结构时。
本研究旨在评估倒凹对Ⅱ类（MOD）修复牙的抗折性和折裂模式的影响。
将90颗人前磨牙随机分为9组：CTR（对照组/完好）；NC（制备洞形，未修复）；RU（修复，无倒凹）；RTB（修复，全角倒凹）；RPB（修复，部分/咬合面倒凹）；EC（开髓，未修复）；EU（开髓，无倒凹）；ETB（开髓，全角倒凹）；EPB（开髓，部分/咬合面倒凹）。用Esthet X树脂复合材料修复牙齿，并在放入PVC圆柱体之前在蒸馏水中储存24小时。以500 kgF的轴向载荷、0.5 mm/min的十字头速度进行轴向加载试验，直至试件断裂。记录抗折性和折裂模式，并使用单因素方差分析和Tukey's HSD检验（α=0.05）对数据进行分析。
在未开髓的测试组中，平均（±标准差）破坏载荷范围为136.56（11.62）至174.04（43.5）kgF。对于开髓的牙齿，抗折性范围为95.54（13.05）至126.51（19.88）kgF。洞缘斜面倒凹可提高抗折性值（p<0.05）并防止灾难性折裂。
洞缘斜面倒凹能够提高开髓和未开髓牙齿的抗折性和折裂模式。
