Hi BDM,
First, don't sweat the small stuff. In a well fabricated crown or bridge abutment, the "space" is between 10-50 microns. This space is filled in with cement and no air space remains. There are millions of units of crown and bridge going diving and not causing a problem.
We actually try to increase this space with the use of die spacer to allow room for the cement. If the space under the crown is too small, then the cement's film thickness may hold up the bite. Using the spacer actually helps the bridge to fit "tighter".
What your dentist told you can indeed be true. The loss of a tooth that would normally be in a functional position very commonly leads to extrusion of the tooth opposite the space and tipping and movement of the tooth/teeth behind the space.
As the opposite tooth begins to extrude, the part of that tooth within the gum is narrower. When the more narrow portions of the tooth begin to come into the mouth, the teeth surrounding that extruded tooth will drift and tip into the narrower space.
Finally, there is tipping, extrusion and migration of both the teeth next to the edentulous site and opposite the site with teeth tipping and migrating next to the extruded tooth. This is called "Posterior Collapse" and can cause many bite and hygiene problems.
This collapse can also create an uneven contour to the gums and periodontal problems may develope.
All this being said, some patients are lucky and have teeth that manage to migrate to a "stable" position. If that occurs and there has been no change in tooth position no periodontal changes, etc., then sometimes the space can be left as is. Only someone who has examined the site can make this call.
Fixed bridges are recommended for this situation. Implants and partial denture can also be used. When appropriate, implants are wonderful. They don't require that additional teeth be prepared. Unfortunately, in cases where there has been movement, there may not be enough room left for either surgery or restoration of the implants.
Partial dentures are the least advantageous treatment. They are removable, they may trap food and they are a mouthfull.
Another consideration in your case is the use of a wisdom tooth as a bridge abutment. They tend to be small teeth and sometimes have short or tapered roots. This makes them less useful for a bridge abutment but may be the only game in town. Again, implants can help avoid using a small bridge abutment.
Finally, the extruded tooth may have to prepared as well to "level" the bite. Without shortening the extruded tooth, you must restore the bite to a less desirable position.
So, if you are a candidate for fixed bridges, don't worry too much about the "space" under the bridge abutments.
Laurence Stein, DDS
:doctor:
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(No representations are made that in any way offer a diagnosis, treatment or cure for any illness or condition, either discussed or implied. Answers to questions are offered as information only and should always be used in conjunction with advice from your personal diving physician/dentist. I take no responsibility for any conceivable consequence, which might be related to any visit to this site.)
