Turky Mohammed, Plotino Gianluca, Mahmoud Nermin Alsayed
Department of Endodontics, Faculty of Dentistry, Minia University, Minia, Egypt.
Department of Endodontics, Faculty of Dentistry, Sphinx University, Assiut, Egypt.
BMC Oral Health. 2024 Dec 27;24(1):1562. doi: 10.1186/s12903-024-05180-y.
To compare the mechanical performance of partially replaced (repaired) intra-coronal restorations to totally replaced ones in root canal-treated teeth.
Thirty maxillary second premolars were selected according to strict criteria, mounted on moulds, and had mesio-occluso-distal (MOD) cavities prepared. Resin composite restorative material was used to perform the initial restoration, followed by aging procedures using thermo-mechanical cycling fatigue to replicate six months of intraoral aging. The specimens were then randomly divided into two groups: a totally replaced restoration (TR) group (n = 15), which involved the preparation of a traditional endodontic access cavity after the complete removal of the pre-existing coronal filling; and a partially replaced restoration (PR) group (n = 15), which involved accessing the tooth through the pre-existing restoration without completely removing it. Root canal preparation and filling procedures were conducted, and the access cavity was sealed with a new resin composite restoration, followed by a new thermo-mechanical cycling aging procedure. Finally, the specimens were submitted to a static fracture test to measure specimen fracture strength and determine the failure mode pattern (repairable fracture or irreparable fracture). Chi-square and t-tests were used for statistical analysis.
Significant differences between the groups regarding their mechanical resistance were found. The average failure load of the TR group was 1115.13 N and 1330.23 N in the PR group (p = 0.002). Regarding the failure modes, the TR group exhibited eight irreparable fractures, while the PR group had four (p = 0.136).
Partially replaced restorations presented higher fracture strength and led to fewer irreparable fractures when compared to totally replaced restorations in root canal-treated teeth.
比较根管治疗牙齿中部分替换（修复）的冠内修复体与完全替换的冠内修复体的力学性能。
根据严格标准选择30颗上颌第二前磨牙，安装在模型上，并制备近中-咬合-远中（MOD）洞形。使用树脂复合修复材料进行初始修复，然后采用热机械循环疲劳进行老化处理，以模拟六个月的口腔内老化。然后将标本随机分为两组：完全替换修复（TR）组（n = 15），在完全去除先前的冠部充填物后制备传统的根管入口洞形；部分替换修复（PR）组（n = 15），通过先前的修复体进入牙齿而不完全去除它。进行根管预备和充填操作，并用新的树脂复合修复体封闭入口洞形，随后进行新的热机械循环老化处理。最后，对标本进行静态断裂试验，以测量标本的断裂强度并确定失效模式类型（可修复断裂或不可修复断裂）。采用卡方检验和t检验进行统计分析。
发现两组之间在力学抗力方面存在显著差异。TR组的平均失效载荷为1115.13 N，PR组为1330.23 N（p = 0.002）。关于失效模式，TR组出现8例不可修复断裂，而PR组有4例（p = 0.136）。
与根管治疗牙齿中的完全替换修复体相比，部分替换修复体具有更高的断裂强度，并且导致的不可修复断裂更少。
