sorry can't type Chinese.

A. based on what you said, I guess the decay you had now was caused by the wisdom tooth which might not erupt in the right place and the decay has been progressed for more than 2 years. Now it's too deep to keep the pulp (basiclly the nerve) intact.

exactly, 昨天那医生就是这么和我说的~ 不过我觉得就算早发现也没有办法补牙阿，因为decay在牙龈以下，对吗？

B. the decay is below the gum margin which will cause any treatment difficult. The small surgery your dentist talked about is not to extend the gum, but it's called crown lengthening--cut off some gum tissue to make the defect area exposed better. This is not for the root canal therapy but for the crown after the therapy.

所以我应该先做根管，再做这个“crown lengthening”,如果它的目的是为了重建crown,那么每个根管术之后都需要它了? 除非不加冠？那么我们学校的dentist就需要refer我两次，一次是去做根管，一次是去做crown lengthening,他好像和我说牙冠重建学校自己能做。

有没有可能做普通的补牙呢？还是因为decay在牙龈以下根本没办法补？所以必须得做根管？

C. If you are not sure about it, get a consultation from an endodontic specialist. You may ask your dentist to refer you one. This is somewhat a complicated case and specialists are better for handling it.

D. personally I don't suggest you go back to do it. I'm not implying anything. You now have a pulpitis and it's better to get treated asap. Second, the quality of RCT and the crown here can be guaranteed if you find a good specialist or even general dentist.

Just my two cents. Good luck.

谢谢mm~