残根牙体剩余量对铸造桩修复后牙根抗力的影响

EFFECTS OF AMOUNT OF RESIDUAL TOOTH ON THE ANTIFRACTURE PROPERTY AFTER THE REPAIR OF CAST POST

目的研究下颌前磨牙残根牙体不同剩余量对铸造桩修复后牙根抗力的影响。方法选取48颗下颌第一前磨牙,根据牙本质肩领的不同分为6组。第1组:根管治疗后全冠修复;第2组:具有1mm的360°包绕的牙本质肩领;第3组:仅颊侧有1mm的牙本质肩领;第4组:仅舌侧有1mm的牙本质肩领;第5组:颊、舌侧有1mm的牙本质肩领;第6组:无牙本质肩领。所有离体牙均用铸造桩及烤瓷熔附金属全冠修复,并以1mm/min的速率加载压缩力,直到出现断裂。结果第2组折裂值为(1383.3±187.6)N,高于其它各组(F=9.33,P<0.01),第1组与第6组间比较亦有统计学意义(P<0.05),其余组间无统计学意义(P>0.05)。结论铸造桩可用于具有牙本质肩领的前磨牙残根的修复。

Objective To evaluate the fracture resistance of endodontically treated mandibular premolars restored with cast posts when different types of ferrule designs were incorporated.Methods Forty-eight mandibular premolars were divided into six groups according to ferrule.In Group 1（control）,the teeth with root canal treatments had a full crown prosthesis.In Group 2,the teeth had 1mm circumferential ferrule.In Group 3,the teeth had a 1mm ferrule only in the buccal region.In Group 4,the teeth had 1mm ferrule only in the lingual region.In Group 5,the teeth had 1mm ferrule in the buccal and lingual region.In Group 6,the teeth had no ferrule.All extracted teeth were restored with cast post and cores and porcelain fused to metal crowns.All experimental teeth were subjected to an increasing compressive force with a crosshead speed of 1mm/min,until fracture occurred.Results The loading force value in the second group was 1383.3±187.6N,which is significantly higher than other groups（P0.01）.The Group One of（1067.6±234.3）N and the Group Six of（718.8±176.3）N showed significant differences（P0.05）.The differences in other groups were not statistically significant.Conclusion Cast post and core can be used to restore the ferrule premolar residual roots.