不同修复方式对前磨牙根管治疗后抗折性的影响

Influence of different restorations on the fracture resistance of endodontically treated premolars with minor loss of dental defect

目的 :研究不同修复方式对缺损前磨牙抗折性的影响,为临床选择合适的修复方式提供参考。方法 :收集因正畸拔除的离体下颌单根前磨牙72颗,随机分为3组,每组24颗,分别制备成面1/3缺损(A组)、面1/2缺损(B组)、邻1/3缺损(C组)模型,每组再随机分为3组,分别采用光固化树脂充填修复(A1/B1/C1)、光固化树脂充填+金属全冠修复(A2/B2/C2)和玻璃纤维桩核+金属全冠修复(A3/B3/C3),各8例。在电子万能实验机上进行静态加载,记录牙体折裂时的载荷值,观察折裂模式,采用SPSS17.0软件包对数据进行统计学分析。结果:在A组中,A2组的折裂载荷最大,且与A1组、A3组的差异显著(P<0.05);B组和C组中,B2、B3组和C2、C3组的折裂载荷均大于B1组和C1组,且差异显著(P<0.05);A、B、C组中,3种修复方式之间的折裂模式无显著差异(P>0.05)。结论 :前磨牙根管治疗后面缺损未超过1/2及邻缺损1/3时,树脂充填后全冠修复可作为优选修复方式。

PURPOSE： To evaluate the influence of 3 different restorations on the fracture resistance of endodontically treated premolars with minor loss of dental defect in order to direct clinical design. METHODS： Seventy-two recently extracted intact and single-rooted human mandibular premolars for orthodontic reason were collected and randomly divided into 3 groups （group A, B, C, n=24）. Each group was respectively prepared into 1/3 defect of occlusal surface （group A）, 1/2 defect of oeclusal surface （group B） and 1/3 defect of proximal-occlusal surface model （group C）. Then each group was divided into 3 subgroups with one restored with a light-curing composite resin （group AI, B1, C1）, one restored with east metal full crowns following a light-curing composite resin （group A2, B2, C2）, and one restored with fiber posts and resin cores and cast full crowns after teeth preparations （group A3, B3, C3, n=8）. Static loading tests were performed on each specimen until cracked.Fracture strength was tested and fracture patterns were examined. The data was analyzed using SPSS17.0 software package. RESULTS： The fracture resistance of subgroup A2 was different when compared with subgroup A1 and subgroup A3. In group B and C, the fracture resistance of teeth in subgroup B2, B3, C2 and C3 were significantly higher than that in subgroup B1 and C1. There was no significant difference in the fracture mode of 3 restorations in group A, B and C. CONCLUSIONS： A composite resin combined with cast metal full crowns can be used as the first choice to restore endodontieally treated premolars with proximal-occlusal 1/3 defects and occlusal defects that do not surpass 1/2 dimension of occlusion.