Jagdish S K, Eazhil Rajamony, Kaviya Karnan Vijila, Imra Kaleel, Sarathchandra Govinda Raj
Department of Prosthodontics and Implantology, Chettinad Dental College and Research Institute, Kelambakkam, IND.
Department of Prosthodontics, Rajas Dental College and Hospital, Kavalkinaru, IND.
Cureus. 2024 Nov 11;16(11):e73447. doi: 10.7759/cureus.73447. eCollection 2024 Nov.
The biologically oriented preparation technique (BOPT) is a conservative tooth preparation method with no defined finish lines. Studies comparing the fracture resistance of endodontically treated teeth (ETT) prepared using BOPT or horizontal finish lines are lacking. The primary objective of this study was to compare the fracture resistance of ETT prepared using BOPT, chamfer finish line, or shoulder finish line and restored with monolithic zirconia (MZ) crowns. The secondary objective was to determine the modes of fracture of ETT with different finish lines.
Forty-five maxillary premolar teeth were endodontically treated and randomly allotted to three tooth preparation methods: Group 1, BOPT; Group 2, chamfer finish line; and Group 3, shoulder finish line. MZ crowns were milled and cemented on their respective tooth preparations. The fracture resistance was tested using a universal testing machine. Maximum fracture load was recorded in Newtons (N). The fracture modes were classified using Burkey's codes and a newly proposed fracture grading.
The highest fracture resistance was seen in samples from Group 1, followed by Group 2, and the least in Group 3. Tukey's post hoc test showed a significant difference between Group 1 and Group 3 (p<0.05) and between Group 2 and Group 3 (p<0.05). No significant differences were found between Group 1 and Group 2 (p>0.05). Code V and Grade 3B fractures were highest in Group 3 samples.
Within the limitations of the present study, it can be concluded that ETT prepared with BOPT and chamfer finish lines had the greatest fracture resistance compared to shoulder finish lines. Teeth prepared with shoulder finish lines had more non-restorable fractures compared to BOPT or chamfer preparations.
生物导向性预备技术（BOPT）是一种无明确边缘线的保守性牙齿预备方法。目前缺乏比较采用BOPT或水平边缘线预备的根管治疗后牙齿（ETT）抗折性能的研究。本研究的主要目的是比较采用BOPT、肩台边缘线或斜面边缘线预备并用整块氧化锆（MZ）全冠修复的ETT的抗折性能。次要目的是确定不同边缘线的ETT的折裂模式。
45颗上颌前磨牙进行根管治疗，并随机分为三种牙齿预备方法：第1组，BOPT；第2组，斜面边缘线；第3组，肩台边缘线。在各自的牙齿预备体上制作并粘结MZ全冠。使用万能试验机测试抗折性能。以牛顿（N）记录最大抗折载荷。采用Burkey编码和新提出的折裂分级对折裂模式进行分类。
第1组样本的抗折性能最高，其次是第2组，第3组最低。Tukey事后检验显示第1组和第3组之间存在显著差异（p<0.05），第2组和第3组之间也存在显著差异（p<0.05）。第1组和第2组之间未发现显著差异（p>0.05）。第3组样本中V型编码和3B级折裂最多。
在本研究的局限性范围内，可以得出结论，与肩台边缘线相比，采用BOPT和斜面边缘线预备的ETT具有最大的抗折性能。与BOPT或斜面预备相比，采用肩台边缘线预备的牙齿出现更多不可修复的折裂。
