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目的 对离体磨牙磨制四种洞型模拟干髓术进行抗折裂负荷测试。方法 取离体完整后磨牙分成5组,每组32颗,A组为对照组(完整牙),B组、C组、D组和E组分别制备成抬面洞、邻(牙合)洞、颊面洞和邻颊(舌)洞,模拟干髓术后进行银汞充填术,然后在10吨液压式万能试验机进行折裂负荷测试。结果 其抗折力分别为:完整牙4324.17N(441.26kgf)、(牙合)面洞型2023.41N9(206.48kgf)。邻(牙合)洞型1873.33N(191.16kgf)、颊面洞型3957.24N(403.81kgf)和邻颊(舌)洞型3103.57N(316.70kgf)。经统计学分析,邻(牙合)洞型和(牙合)面洞型抗折力明显低于完整牙抗折力(P<0.01),其次是邻颊(舌)洞型抗折力也低于完整牙抗折力(P<0.05)但颊面洞型抗折力与完整牙抗折力又无明显差异(P>0.05),邻颊(舌)洞型抗折力又明显高于邻(牙合)洞型抗折力(P<0.05)。结论 颊面洞抗折力最好,邻颊(舌)洞型抗折力优于邻(牙合)洞型。
OBJECTIVE To test the anti-cracking load of four kinds of mothods in vitro grinding. Methods The intact molars were divided into 5 groups (32 in each group). Group A was the control group (intact teeth). Group B, group C, group D and group E , Buccal cavity and buccal cavity (tongue), amalgamation was performed after simulating dry-marrow operation, and then the stress test was carried out on a 10-ton hydraulic universal testing machine. The results of their resistance to fracture were: complete teeth 4324.17N (441.26kgf), (occlusal) face hole 2023.41N9 (206.48kgf). 1873.33N (191.16kgf), 3957.24N (403.81kgf) for buccal cavity and 3103.57N (316.70kgf) for buccal cavity. The statistical analysis showed that the fracture resistance of orthodontic and occlusal cavities was significantly lower than that of intact teeth (P <0.01), followed by that of the adjacent buccal and lingual cavities (P <0.05). However, there was no significant difference in the bending strength between buccal cavities and intact teeth (P> 0.05). The bending resistance of the buccal cavity was significantly higher than that of the adjacent cavities (Occlusal) hole type of anti-stress (P <0.05). Conclusions The buccal cavity is the best in terms of the bending resistance, and the bending strength of the buccal cavity is superior to the orthodontic cavity.