The Importance of Properly Adjusting Crowns (Porcelain, Gold and Zirconium)
When a dentist is ready to cement a crown it is important to verify the fit of the crown first. First of all the prepared tooth must be thoroughly cleaned of any debris from left over temporary cement particles that may remain on the prepared tooth. This can only be accomplished well with magnification through the use of special glasses called loupes. Without the use of magnification, one cannot be sure that all of the debris is gone. A small particle of temporary cement can prevent the permanent crown from fully seating to its intended position and lead to decay and food getting between teeth.
Another thing that can prevent the crown from seating completely is the presence of gum tissue that tends to grow over the prepared tooth quickly. When the crown is seated over the tooth it is highly recommended to place retraction cord in order to displace the gum tissue in order to prevent the gum tissue from getting pinched between the prepared tooth and the crown. Tissue which becomes pinched between the crown and the tooth will become necrotic and cause a gap around the whole crown, opening the door to decay and sensitivity.
Once the tooth is cleaned well and the tissue is managed, the crown can be tried on and adjusted to fine tune the fit. The first step is to adjust the contacts the crown makes with the tooth in front of it and the tooth behind it. This is done using a very thin floss which is not waxed. Using a floss that is too thick during this step will lead to over adjustment of these contacts allowing food to get in between the teeth where it can cause inflammation, decay and bad breath. Once again it is important to use magnification to do these adjustments properly. The crown is carefully adjusted until the contact between the teeth allows the thin floss to pass through without shredding but still with noticeable resistance.
The last step in the adjustment process is to make sure the crown meets the teeth that oppose it well. When the patient bites down on the crown, the tooth that it chews against should not touch the crown any harder that the other teeth touch each other. It is not enough to check for this in only a center biting position. The crown must be checked in sideways chewing or grinding movements as well. Back teeth are not designed to bump into each other in lateral or grinding movements. If they do this can lead to TMJ problems and muscle splinting. Therefore, the dentist must check for these potential interferences.
All of the above items need to be double checked after the cementation of the crown as well. When done well, crowns are the strongest and one of the most durable restorations dentists can provide.
At Springs Dental in Saratoga Springs, NY, we use surgical loupes to magnify what Dr. Stanley J. Lis and Dr. Joshua S. Bronner examine so that things appear four times larger and they can be four times more precise and four times more thorough. Our doctors make sure that dental patients who come to our practice in Saratoga Springs will benefit from this thoroughness and accuracy.