Kuşuçar Ayşe Nur, Kırıcı Damla
Department of Endodontics, Faculty of Dentistry, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey.
Department of Endodontics, Faculty of Dentistry, Akdeniz University, Antalya, Turkey.
BMC Oral Health. 2025 Mar 27;25(1):443. doi: 10.1186/s12903-025-05757-1.
This study used micro-computed tomography (µCT) to assess the post space preparation systems [Rebilda (VOCO), RelyX (3M)] and preparations of varying lengths to create root dentin cracks.
Forty extracted maxillary first premolars with two roots were randomly divided into four groups. Teeth were decoronated to a length of 18 mm. Following root canal treatment, first µCT scans were performed. Post spaces were prepared with Rebilda post drills at 1/2 of the working length (WL) in Group 1 and at 2/3 of the WL in Group 2, while post spaces were prepared with RelyX post drills at 1/2 of the WL in Group 3 and at 2/3 of the WL in Group 4. After post space preparation, second µCT scans were performed. Dentinal cracks were detected by comparing the first and second µCT scan images, which were classified as "newly formed cracks", "advanced cracks" and "completed cracks". The chi-square test was used to compare among the groups, with a p-value of < 0.05 considered statistically significant.
No statistically significant differences were observed between the groups for completed and advanced cracks (P > 0.05). In terms of newly formed cracks, the Rebilda-2/3 group showed more cracks than the RelyX-1/2 group, and the RelyX-2/3 group had more cracks than the RelyX-1/2 group (P < 0.05).
Completed and advanced cracks were observed in all groups, while no newly formed cracks were detected in the RelyX-1/2 group. The type of post drill and the preparation length are crucial factors in preventing the development of root dentinal cracks. Preparing 1/2 of the canal length may be a safer preparation length, and the RelyX drill may pose less risk of inducing root dentinal cracks.
本研究使用显微计算机断层扫描（µCT）来评估桩道预备系统[Rebilda（VOCO）、RelyX（3M）]以及不同长度的预备对牙根牙本质产生裂纹的影响。
将40颗拔除的上颌第一前磨牙随机分为四组。将牙齿截短至18毫米长。进行根管治疗后，首先进行µCT扫描。第1组使用Rebilda桩钻在工作长度（WL）的1/2处预备桩道，第2组在WL的2/3处预备；第3组使用RelyX桩钻在WL的1/2处预备桩道，第4组在WL的2/3处预备。桩道预备后，进行第二次µCT扫描。通过比较第一次和第二次µCT扫描图像来检测牙本质裂纹，这些裂纹被分类为“新形成的裂纹”“进展性裂纹”和“完全裂纹”。采用卡方检验对各组进行比较，p值<0.05被认为具有统计学意义。
在完全裂纹和进展性裂纹方面，各组之间未观察到统计学上的显著差异（P>0.05）。在新形成的裂纹方面，Rebilda - 2/3组的裂纹比RelyX - 1/2组更多，且RelyX - 2/3组的裂纹比RelyX - 1/2组更多（P<0.05）。
所有组均观察到完全裂纹和进展性裂纹，而RelyX - 1/2组未检测到新形成的裂纹。桩钻类型和预备长度是防止牙根牙本质裂纹形成的关键因素。预备根管长度的1/2可能是更安全的预备长度，且RelyX钻诱发牙根牙本质裂纹的风险可能较小。
