柱形和锥形纤维桩修复离体上前牙抗折性的比较

Comparison of the fracture resistance of pulpless upper anterior teeth restored with tapered and parallelsided fiber posts

目的探讨柱形和锥形纤维桩修复对根管治疗前牙的抗折强度和折裂喇的影响。方法24颗上前牙随机分成3组．每组8颗。A组：柱形纤维桩-树脂核-全瓷冠；B组：锥形纤维桩-树脂核-全瓷冠；C组：直接全瓷冠修复。测定各样本的抗折载倚值．并观察折裂型。SPSS软件行统计学分析。结果各组样本的平均抗折载荷值分别为：（468．8±142．5）、（440．2±202．7）、（159．0±147．6）N。对各组样本的抗折载荷值进行随机区组设计的方差分析．差异无统计学意义（P〉0．05）。对各组样本的折裂型进行Fisher确切概率法检验，组间差异有统计学意义（P〈0．05）．A纰小利型牙折发生率为75％．大于B组12．5％及C组12．5％。结论柱形及锥形纤维桩修复刈。根箭治疗牙的抗折强度无显著影响。但一旦发生牙折，锥形纤维桩修复牙较柱形纤维桩修复牙不利型牙折发生率小．临床再次修复概率大．提示相对于柱形纤维桩，锥形纤维桩更有利于保存余留牙体组织。

Objective To investigate fracture resistance and fracture patterns of maxillary ante riot endodontically treated teeth restored with two different shapes of glass fiber post systems. Methods Twenty-four human sound nlaxillary anterior teeth of similar size were collected, and randomly divided into 3 groups, 8 teeth each. After endodontical treatment, they were given tbe follow ing treatments： Group A： parallel glass fiber posts （cohene parapost fiber lux） and composite core; Croup B： taper glass fiber posts （coltene parapost taper lux） and composite core; （;roup C （control group）： intact endodonticdly treated teeth. Teeth in （;roups A and B reserved 2 mm dentin ferrule. Then the teeth were ,repared and restored with IPS e. max Press all ceramic crowns. All the teeth were emhedded in acrylic resin 2 mm below the cementoenamel junction （CEJ）, with the silicon impression material stimulating periodontal membrane. All the specimen were loaded under a universal testing machine, at the palatal junction of incisor third and middle third, with an angle of 135 degree to the longitudinal axis of the tooth until fracture occurred, at a cross-head speed of 1. 0 mm/min. Fracture loads and patterns were recorded. Statistical analysis was performed using SPSS software. Results The mean fracture loads in the three groups were as follows： （468.8±142.5） N, （440.2± 202.7） N, and （.159.0 ±147.6） N, respectively. There was no significant difference in fracture loads among groups （P〉0.05）. The incidence of unfavorable fracture in Group A was higher than C-roups 13 and C. Conclusions There is no significant difference in fracture strength between parallel and taper fiber post grc,mps. However, the group with parallel fiher posts demonstrates a higher risk of unfavorable fracture than the group with taper fiber posts, which indicates that ta,oer fiber posts are more favorable to preserve the remaining tooth structure.