Department of Operative and Esthetic Dentistry, Faculty of Dentistry, University of Szeged, Szeged, Hungary.
Department of Periodontology, Faculty of Dentistry, University of Szeged, Szeged, Hungary.
J Mech Behav Biomed Mater. 2022 May;129:105143. doi: 10.1016/j.jmbbm.2022.105143. Epub 2022 Mar 4.
The aim of this study was to evaluate the effect of the amount of periodontal support and the presence or absence of root amputation on the fracture resistance of intracoronally splinted maxillary molar teeth.
48 extracted human upper first molars and 48 s premolars were included in the study. All teeth underwent standard mesio-occluso-distal (MOD) (molars) and standard occluso-distal (OD) (premolars) cavity preparation. After the preparation, all molars were root canal treated, and 48 molar-premolar units were created by intracoronal splinting. The units were randomly divided into 4 groups (Groups A-D, 12 units per group): in Groups C and D, the disto-buccal (DB) roots of the molars were amputated, while in Groups A and B, no root amputation was performed. All units were embedded in methacrylate resin at different levels: in Groups A and C, at 4 mm apically from the cemento-enamel junction (CEJ), while in Groups B and D, at 6 mm apically from the CEJ, mimicking the different stages of furcation involvement. All units were submitted first to dynamic and then to static, load-to-fracture mechanical testing. Fracture resistance values were recorded fracture mode was analysed.
During the load-to-facture test, Groups A and B (without root amputation) were characterized by significantly higher fracture resistance values compared to Groups C and D (with root amputation) (p < 0.05). Regarding fracture mode, irreparable fracture was more frequent in Group D (with root amputation and advanced furcation involvement) than in any other group (n = 8).
Root amputation has a negative effect on the fracture resistance of intracoronally splinted upper first molar-second premolar units with modeled furcation involvement.
本研究旨在评估牙周支持量的多少以及是否进行根截断对根管内夹板上颌磨牙抗折能力的影响。
本研究纳入了 48 颗人上颌第一磨牙和 48 颗第二前磨牙。所有牙齿均进行了标准的近中-颊舌-远中（MOD）（磨牙）和标准的颊舌-远中（OD）（前磨牙）洞型制备。制备完成后，所有磨牙均进行根管治疗，48 个磨牙-前磨牙单位通过根管内夹板连接。将这些单位随机分为 4 组（A-D 组，每组 12 个单位）：C 组和 D 组磨牙的颊侧远中根被截断，而 A 组和 B 组磨牙未进行根截断。所有单位均用甲基丙烯酸树脂包埋，包埋高度分别为：A 组和 C 组距离釉牙骨质界（CEJ） 4mm 处，B 组和 D 组距离 CEJ 6mm 处，模拟不同的分根病变阶段。所有单位首先进行动态加载，然后进行静态加载，直至发生断裂。记录抗折强度值，并分析断裂模式。
在加载至断裂试验中，未进行根截断的 A 组和 B 组（无根截断）的抗折强度值明显高于进行了根截断的 C 组和 D 组（有根截断）（p<0.05）。关于断裂模式，D 组（有根截断和晚期分根病变）的不可修复性断裂比其他任何组都更常见（n=8）。
根截断对建模有分根病变的根管内夹板上颌第一磨牙-第二前磨牙单位的抗折能力有负面影响。
