Fouda Shaimaa M, Ellakany Passent, Gad Mohammed M, Bahgat Hala A, Ayad Neveen M, Ateeq Ijlal Shahrukh, Dehailan Laila Al, Mahrous Amr A
Department of Substitutive Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia.
Department of Removable Prosthodontics, College of Dentistry, Al-Ahram Canadian University, 6th of October 3221405, Egypt.
Materials (Basel). 2023 Jul 5;16(13):4830. doi: 10.3390/ma16134830.
Occlusal rest provides support for removable partial dentures (RPD). Rest seats are ideally prepared in enamel, but the abutment teeth might be restored or need restorations. This study compared the fracture strength of abutments restored with composite to amalgam restorations after rest seat preparation. Disto-occlusal cavities were prepared in 30 extracted human maxillary premolars. The specimens were allocated in three groups (n = 10) based on the type of restoration. All the specimens were exposed to thermomechanical aging followed by cycling loading. Fracture strength was tested using a universal testing machine, and then, the fracture mode was recorded. The data were analyzed using Kruskal-Wallis test with a significance level set at 0.05. The fracture mode was recorded as catastrophic or non-catastrophic. The fracture strength between all tested groups showed no significant difference. The highest and lowest fracture strength were recorded on amalgam and Tetric N-Ceram groups, respectively. Composite Tetric N-Ceram showed equal distribution of fracture sites on the restorative materials and teeth, it also displayed the highest number of non-catastrophic fractures unlike other groups where the fracture occurred more within the restorations. The fracture strength of composite was comparable to that of amalgam restorations with prepared rest seats.
牙合支托为可摘局部义齿（RPD）提供支持。理想情况下，支托窝应预备在牙釉质内，但基牙可能已进行修复或需要修复。本研究比较了在预备支托窝后，用复合树脂修复与用汞合金修复的基牙的断裂强度。在30颗拔除的人上颌前磨牙上制备远中牙合面洞。根据修复类型将标本分为三组（n = 10）。所有标本先进行热机械老化，然后进行循环加载。使用万能试验机测试断裂强度，然后记录断裂模式。使用Kruskal-Wallis检验分析数据，显著性水平设定为0.05。将断裂模式记录为灾难性或非灾难性。所有测试组之间的断裂强度没有显著差异。汞合金组和Tetric N-Ceram复合树脂组分别记录到最高和最低的断裂强度。Tetric N-Ceram复合树脂在修复材料和牙齿上的断裂部位分布均匀，与其他组相比，它还显示出非灾难性骨折的数量最多，其他组的骨折更多发生在修复体内。复合树脂的断裂强度与预备支托窝后的汞合金修复体相当。
