纤维桩不同修复方法对薄弱根管抗折性能影响的实验研究

Fracture resistance of maxillary anterior teeth with flared root canals restored with fiber posts by 3 methods

目的:探讨纤维桩不同修复方法对薄弱根管抗折性能的影响。方法:将32颗离体上颌中切牙随机分为A、B、C、D4组(n=8)。将A、B、C组牙预备成漏斗状薄弱根管,采用纤维桩3种不同的修复方法修复;D组为对照组,采用正常根管预备,用单根纤维桩复合树脂核修复。桩核修复后,4组均行铸造金属全冠修复。在电子万能试验机上持续加载至试样牙发生折裂。记录折裂时的加载载荷和折裂模式。结果:A、B、C、D组的断裂载荷(N)分别为295.94±69.11、450.51±54.68、479.37±77.81、618.51±87.42(F=118.127,P=0.000),B组与C组比较,P>0.05,其余组间比较,P<0.05。各组间可修复性折裂模式差异无统计学意义(P>0.05)。结论:复合树脂重塑根管后应用纤维桩树脂核和纤维桩主桩加辅桩复合树脂核能显著提高薄弱根管的抗折性能,折裂模式有利于二次修复。

Objective： To investigate the influence of 3 methods of fiber posts on fracture resistance of maxillary anterior teeth with flared root canals. Methods ： 32 human maxillary central incisors were assigned randomly to 4 groups （ n = 8 ）. The crowns of the teeth were removed at a level 2 mm incisal to the cementoenamel junction（CEJ）. After root canal therapy, flared canals were simula- ted in 3 groups. The flared canals were reinforced with resin cement （ group A ） , resin composite （ group B ） and accessory posts （ group C） respectively. In group D flared canals were not created. The same size fiber posts were cemented with resin cement in all groups. After posts cementation and composite resin core formation, all teeth were restored with metal crowns. Then the roots of the teeth were embedded in acrylic resin blocks up to 2 mm below the CEJ. The samples were loaded in a testing machine until failure occurred. Results： The maximum load value （N） for fracture of group A, B, C and D was 295.94 ± 69. 11, 450.51 ± 54.68, 479.37 ± 77.81 and 618.51±87.42 respectively（ F = 118. 127, P = 0.000） ; group B vs C, P 〉 0.05, between each 2 of the other groups, P 〈 0.05. No significant differences were found among the groups in the number of repairable fracture patterns （ P 〉 0.05 ）. Conclusion： Reinforcement of flared canal with resin composite and accessory posts can increase the fracture restance of the tooth root and the most of fracture patterns are beneficial for the second repair.