Faculty of Medicine, University of Ulm, Albert-Einstein-Allee 7, 89081, Ulm, Germany.
Dentsply Sirona, DeTrey-Strasse 1, 78467, Konstanz, Germany.
Sci Rep. 2024 Jun 8;14(1):13205. doi: 10.1038/s41598-024-63396-y.
The evidence base on minimally invasive endodontic (MIE) treatment is limited. This study investigated the influence of MIE shaping on vertical root fracture (VRF) resistance and crack formation of root canal filled teeth. Human maxillary central incisors were randomized into six groups (n = 18, power = 0.9) and embedded in acrylic blocks with artificial periodontal ligaments. The root canals were either instrumented to size #40 and 0.04 taper (+MIE) or enlarged to ISO size #80 (-MIE). The canals were filled with cement-based (C) or adhesive resin-based (A) sealers in single-cone technique. The controls received no treatment or were left unfilled. After chewing simulation (staircase method, 25-150 N, 120,000×), the crack formation on the root surface was analyzed using stereomicroscope/digital imaging and classified (no defect, craze line, vertical crack, horizontal crack). Subsequently, the samples were loaded until fracture. The incidence of defects (56% vertical cracks) was not significantly different between the groups (p ≥ 0.077). VRF resistance was significantly higher in untreated teeth than in +MIE/C (p = 0.020) but did not significantly differ between the other groups (p ≥ 0.068). Minimal canal shaping did not reduce the risk of vertical root fracture and defects of root canal filled teeth.
微创牙髓治疗（MIE）的证据基础有限。本研究调查了 MIE 成形对根管充填牙垂直根裂（VRF）抵抗力和裂纹形成的影响。将上颌中切牙随机分为六组（n=18，功率=0.9）并嵌入带有人工牙周韧带的丙烯酸块中。根管要么用 #40 和 0.04 锥度的器械扩大（+MIE），要么用 ISO #80 扩大（-MIE）。根管用水泥基（C）或黏附树脂基（A）密封剂进行单锥技术充填。对照组未接受治疗或未填充。咀嚼模拟（楼梯法，25-150 N，120,000×）后，使用立体显微镜/数字成像分析根表面的裂纹形成情况，并进行分类（无缺陷、微裂纹、垂直裂纹、水平裂纹）。随后，对样品进行加载直至断裂。各实验组之间的缺陷发生率（56%的垂直裂纹）无显著差异（p≥0.077）。未处理的牙齿的 VRF 抵抗力明显高于+MIE/C（p=0.020），但与其他组之间无显著差异（p≥0.068）。最小的根管成形并不能降低根管充填牙的垂直根裂和缺陷风险。
