Q: I have a cavity under my cap and my dentist says he’ll need to make me a new cap. Why can’t he just use the old one?
A: Great question! Utilizing an existing crown or cap (same thing just different terms) when there is a cavity around it is possible in only the best of circumstances.
Your dentist cannot see the extent of the decay under the crown. Also, in most cases an x-ray is not diagnostic because the crown will obscure the tooth.
In order for decay to show up on an x-ray there has to be extensive destruction of the natural tooth. If the decay is below the crown area then a filling can usually be placed leaving the crown intact. If the decay extends underneath the crown then your dentist will most likely need to remove the crown by sectioning it in order to get access to the decay.
If the crown is loose it is sometimes possible to remove it without damaging it or the tooth underneath. However, once the decay has been removed and the decayed portion is replaced and built back up the shape of the tooth has been altered and the original crown won’t fit. At this point trying to retrofit it is not advisable as it will never be the same as before the tooth was altered. In addition, because the tooth has been altered you will always be susceptible to decay again.
It’s similar to a lock and a key. The key that was made for your car won’t open your house. The crown is precisely constructed to fit just that tooth and that tooth only. It is better to follow your dentists advice and begin the process anew. That way you can be sure that the new crown will be solid and long lasting and the tooth underneath it is strong and healthy.
Questions can be sent to Fred Eck, D.D.S. at Marco Dental Care, 950 N. Collier Blvd., Suite 305, Marco Island; call 389-9400 or visit marcodentalcare.com. He received his Doctor of Dental Surgery at the University of Detroit Mercy and is licensed by the Florida State Board of Dentistry.