摘要
目的研究单壁箍结构的位置和高度对牙根抗力的影响。方法将35颗离体完整下颌第一前磨牙随机分为7组。第1～3组:分别仅保留颊侧、舌侧、邻面高度1 mm的箍结构;第4～6组:分别仅保留颊侧、舌侧、邻面高度2 mm的箍结构;第7组:无箍结构。所有离体牙均用纤维桩、树脂核、Ni-Cr合金全冠修复。电子万能实验机以与牙长轴成135°于颊尖顶加载、横梁位移速度1.0 mm/min,直至试件出现断裂,并对折裂强度进行统计分析。结果箍结构的位置对牙齿抗力存在明显影响(P<0.025),颊侧组抗力大于舌侧组(P<0.025)。第4组的折裂强度最高(395.06±50.17)N,明显高于第2、3、5、7组(P<0.025),其余组间未见统计学差异。所有试件均未发生不可再修复性破坏。结论单壁箍结构的位置离受力侧越近,牙齿的抗力越大;主要受力侧保留至少2 mm高度的单壁箍结构,相比无箍结构者可明显提高牙齿抗力。
Objective To evaluate the effect of one-wall ferrule in different location and heights on fracture resistance of tooth roots.Methods Thirty-five intact extracted mandibular first premolars were randomly divided into seven groups： Group 1 to Group 3： teeth with 1 mm ferrule only in the buccal,lingual or proximal region separately;Group 4 to Group 6： teeth with 2 mm ferrule only in the buccal,lingual or proximal region separately;Group 7： teeth with no ferrule.All the extracted teeth were restored with fiber posts,composite cores and metal full crowns.Each specimen was subjected to an increasing compressive force at buccal spire at 135 degrees from the long axis in a universal testing machine with a crosshead speed of 1.0 mm/min until fracture.Fracture resistance was analyzed statistically.Results The fracture resistance of teeth was significantly affected by the location of ferrule（P＆lt;0.025）,and the mean failure strength of the buccal group was significantly higher than that of the lingual group（P＆lt;0.025）.Group 4 demonstrated the highest mean failure strength value among all groups,and the value was significantly higher than that of group 2,group 3,group 5,and group 7（P＆lt;0.025）.The remaining groups showed no statistical difference.All the fracture modes of specimens were repairable.Conclusions The fracture strength is higher when the dentin wall of ferrule was closer to the side loading force.Compared with teeth with no ferrule,to provide a one-wall ferrule at least 2 mm high on the main loading force side can improve the fracture strength of teeth.
出处
《口腔医学》
CAS
2013年第5期303-306,共4页
Stomatology
基金
江苏高校优势学科建设工程资助项目
关键词
箍结构
抗力
桩核
ferrule
fracture resistance
post and core
作者简介
通信作者：吴凤鸣Tel：（025）85031831 E—mail：wudent@sina．com
