复合树脂直接与间接修复后的牙体抗力实验研究

In vitro study on fracture resistance of teeth restored with direct and indirect composite resin

目的了解牙齿直接和间接用树脂修复后的牙体的抗力特性。方法40颗无龋前磨牙,制成MOD洞,然后分成4组,分别以Renew树脂直接充填,Renew直接嵌体修复,Tescera间接嵌体修复,制洞后不加修复。另以10颗完整前磨牙为对照。对上述所有牙齿采用力学模型静态力学加载实验,并进行对比分析研究。结果备洞未修复组牙齿的断裂载荷最小,与Renew树脂充填、Renew直接嵌体修复、Tescera间接嵌体修复及完整牙组有显著性差异(P<0.05);Renew树脂充填、Renew直接嵌体修复、Tescera间接嵌体修复和完整牙组之间抗断裂载荷无显著性差异(P>0.05)。在断裂模式上,Renew树脂充填组、Renew直接嵌体修复组和Tescera间接嵌体修复组分别出现9、3和1个样本树脂断裂。结论复合树脂充填和嵌体修复都能提高缺损牙齿的牙体抗力,复合树脂经过复合固化处理后力学性能有所提高。复合树脂不同固化处理对牙体抗力无明显影响。

Objective：To evaluate the fracture resistance of teeth restored with direct and indirect restorations of composite resin. Method：Fifty maxillary premolars were divided at random into five groups with ten teeth in each group. Standardized MOD cavities were prepared in the teeth of group 1,2,3 and 4 ,and then restored with ：①direct filling composite resin（ Renew, Bisco USA ）, ②direct composite inlay （ Renew Bisco USA ）, ③indirect composite resin inlay（Tescera Biseo, USA）, and ④ unrestored. Intact teeth（ group ⑤） were served as the control. The fracture resistance of the specimens was tested by loading compressive force at 1 mm/min using a universal testing machine. Result：The breaking load （ kN ） in group ①, ②, ③, ④ and ⑤ was 2. 06 ± 0.76,2. 30 ±0.49, 2.62 ±0.68,1.24 ±0.44 and 2.40±0.71 respectively. There was no significant difference among group ①,②, ③ and ⑤（P 〉 0.05 ）. Significant difference was found between group ④ and ①, ②,③ or ⑤（P 〈 0.05 ）. Conclusion：Both direct and indirect composite resin can strengthen the fracture resistance of restored teeth.