中文摘要：

目的 对比分析复合树脂与聚合瓷在牙体缺损修复术中对牙体抵抗力的影响.方法 选取48颗正畸拔除且无龋坏的单根上颌前磨牙,将所有样本按随机数法分为A、B、C、D四组,每组均为12颗.A组不给予处理,B组接受单纯复合树脂填充修复,C组接受复合树脂覆盖牙尖填充修复,D组接受聚合瓷嵌体覆盖牙尖修复.完成修复后测试不同组别的抵抗力,并根据牙体的劈裂情况对其进行分类.结果 ①抗折强度：A组（1010.31±292.81）N,B组（809.62±205.37）N,C组（1109.47±298.74）N,D组（1140.58±285.26）N,其中C组与D组的抗折能力均优于B组（q=3.802、4.197,P＜0.05）,C组与D组间的差异比较无统计学意义（q=0.394,P＞ 0.05）.②劈裂形式：A组Ⅰ型2颗,Ⅱ型10颗;B组Ⅰ型1颗,Ⅱ型11颗;C组Ⅰ型1颗,Ⅱ型11颗;D组Ⅰ型6颗,Ⅱ型6颗.D组的劈裂形式明显优于B、C组（x2=5.042,P=0.025）.结论 复合树脂与聚合瓷嵌体均有利于提高牙体缺损修复术中牙齿的抗折强度,而采用聚合瓷牙齿的劈裂形式要优于采用复合树脂.

英文摘要：

Objective To compare the effect of composite resin and polymer ceramic onlay on fracture resistance of endodontically treated teeth.Methods 48 noncarious single-rooted maxillary premolars extracted for orthodontic reason with smature apice were randomly divided into group A,group B,group C,group D with 12 samples in each group.Group A was treated as control group; group B was treated with composite resin restoration without cusp capping; group C was treated with composite resin restoration with cusp capping; group D was treated with ceramage ceramic onlay restoration with cusp capping.Fracture resistance and failure mode were compared between the 4 groups.Results ①The fracture resistance：group A were （1010.31 ±292.81） N; group B were （809.62±205.37） N; group C was （1109.47±298.74） N; group D were （1140.58±285.26） N.The fracture resistance of group C and group D was better than that of the group B （q =3.802,4.197,P ＜ 0.05）,while the difference of group C and group D was not statistically significant （q =0.394,P ＞ 0.05）.②Patterns of fracture：2 teeth of type Ⅰ and 10 teeth of type Ⅱ were found in group A; 1 tooth of type Ⅰ,11 teeth of type Ⅱ were found in group B; 1 tooth of type Ⅰ,11 teeth of type Ⅱ were found in group C; 6 teeth of type Ⅰ,6 teeth of type Ⅱ were found in group D.The fracture of group D was obviously better than that of group B and group C,the differences were statistically significant （x2 =5.042,P =0.025）.Conclusion Cuspal coverage with composite resin restoration or polymer ceramic onlay is in favor of fracture resistance of endodontically treated teeth while polymer ceramic onlay restoration is superior to composite resin restoration in fracture pattern.