您說的是一種情形，

A dentist will often recommend crowns for teeth that they see are at risk for fracture, such as teeth that have very large fillings, or teeth that show fracture lines (especially if the patient has a history of grinding or clenching).

所有跟帖： 

• 看來你也沒搞懂，你光看definition有什麽用？ -goingplace- ♀ (0 bytes) () 06/21/2019 postreply 17:21:47

• 用處是因為我自己有過不需要root canal， 隻加crown的經曆 -Angel06- ♀ (0 bytes) () 06/21/2019 postreply 17:32:46

• 當牙齒碰到冷熱都會疼痛時，說明牙齒蛀到牙髓了，這時醫生做root canal弄幹淨神經，之後的牙齒雖然仍然好用， -goingplace- ♀ (210 bytes) () 06/21/2019 postreply 17:41:16