A few years ago I had a metal crown put on a molar. What can happen to a tooth if the crown remains on but a hole in it remains?

Hello Don,The hole in your crown will most certainly lead to decay.  I would recommend having your crown replaced sooner rather than later.  Also, grinding your teeth can cause tooth mobility, tooth sensitivity,
tooth fracture and jaw problems. I would strongly recommend a custom fitted
nightguard to prevent further damage to your teeth and gums. Good luck and I hope this
helps. Follow me if you have more questions.
Sarah
Thompson, DMD
St.
Louis, MO area (O'Fallon, IL)
Real Self
100

Yes, the hole in the crown is a direct pathway to the tooth, which will lead to decay formation. Its important that it be comprehensively examined by your dentist and cared for. Keep in mind that the wear on your old crowns is an indication of heavy trauma caused by your occlusion, or bite. It is important the this will be taken into account by your dentist and addressed as well.All the best,

The hole in your dental crown will definitely lead to decay. Sugar and acid (the things that cause decay) will get under the crown via this hole.  This decay may be more extensive the longer that the hole has been there (or the longer you wait to fix it). If the tooth under the crown is too short, then you many need to have an additional procedure called crown lengthening to provide more tooth structure for a new crown to be cemented to. If the crown keeps coming off or wearing down due to grinding, then you may eventually need to have the tooth extracted and a dental implant placed to replace it. Another option would be to treat your teeth grinding with either TMJ therapy and/or a TMJ appliance or night guard. 

You are correct, a hole will lead to decay.  I have replaced crowns with holes and the decay was much more than expected due to the fact that we can't see inside crowns to see where the decay goes. But insanity is doing the same thing over and expecting a different result.  If you are grinding holes, then the bite should be addressed.  If the tooth is too short for a crown to stay on, then treatment should be done to create more room (osseous crown lengthening) or remove the tooth and place an implant.