Conclusion: Metronidazole Tablets placed into the extraction wound of impacted teeth and pulpless teeth may provide prevention against dry socket.

结论：甲硝唑片置入阻生齿或无髓牙拔牙窝内可以起到预防干槽症的作用。

Objective: To sum up and analysis the causes of failure about treating pulpless and discolored anterior teeth with the method of interior tooth bleaching.

目的：总结和分析用内漂白方法治疗无髓变色前牙的失败原因。