Assuming that a bridge is the right alternative for restoring your missing tooth, how do you decide which type of bridge is best?
Well luckily, when it comes to treatment planning, the dentist is a professional used to making these decisions, so don’t feel overwhelmed; they will present you with the different options.
Fixed bridgework is essentially crowns holding a fake tooth or teeth. As such the dentist must take into account all of the information we discussed when 'choosing a crown
There are some additional considerations to appreciate that are specific to bridges. These factors are weighted differently and your dentist will put them in the context of your desired outcome, timing, expectations and finances in helping you to make the right decision.
Factor to consider include:
- The state of the abutment teeth
These are the teeth to be used to support the bridge. Are they healthy and untouched by dentist hands, or are they heavily restored and filled, or even crowned?
If they are untouched, the more conservative a bridge the better- an all-porcelain fixed-fixed bridge would involve a lot of drilling down of your tooth and would be better avoided in favour of an implant.
The more heavily filled teeth are, the more having crowns on them, as part of the bridge will have a protective role rather than a destructive one. Small fillings can sometimes be replaced and incorporated into an inlay bridge or used to gain extra surface area for bonding-in a 'sticky type' bridge.
Glass fibre re-inforced composite bridges are not very widely performed, but if your dentist does them, they can be a good option when you have largely healthy teeth that you want to protect.
- The position of the tooth
(i) For front teeth, these are suitable options:
-Resin retained or bonded bridges.
(ii) For back teeth,
all bridge designs are possible- it just depends on the situation as to whether they are appropriate. The vast majority of the time- the extra forces that need to be absorbed at the back of the mouth from chewing make the resin-retained bridge unsuitable.
The best aesthetic bridges are unarguably the fixed-fixed type bridge or single fixed cantelever. The metal wings of a resin-retained bridge (RRB) which bond it to the teeth next door, can cause some greying of the holding teeth. Porcelain bonded bridges can now be made which act on the same principle (still minimal drilling), but they do away with any metal and its associated problems.
A single cantelever is commonly used to replace a lateral incisor using the canine as the abutment. Canine teeth have very long strong roots, so it is not always necessary to prepare the central incisor as well- unless there is a problem with it avoiding the need and extra expense of a fixed-fixed design. The lateral incisor, (one of the most common teeth to be lost) is also replaced fairly well with a RRB if the conditions in your mouth (bite etc.) are favourable.
The further back in your mouth that you go, the less a small amount of metal work matters- that said you may insist, for aesthetic reasons, you would like an all porcelain bridge to be made.
- If an abutment tooth has had root canal treatment
If one of the supporting teeth has had a root canal filling
, protecting it with a crown is a good idea anyway. So a fixed-fixed or fixed movable design would be ideal. However, if it also has a post into the root canal, this tends not to be regarded as the most ideal situation for supporting a bridge. Pressures on the bridge can risk the post fracturing the root- this would cause the tooth to be lost and a major rethink would be needed.
When I say it is not ideal, I mean, we (dentists) still have to do it in many situations when our options are limited, but it is a risk you need to be aware of. A post crown as part of a bridge, in say a bruxist with a heavy grinding habit, would not be the best idea.
- How long you want it to last
There are many factors that will determine the success of each individual bridge
. Generally speaking, resin-retained bridges are regarded as the least reliable because they involve the least tooth preparation and rely entirely on the strength of the cement.
If this was to fail, it can probably be stuck back in, though the length of time it would be expected to last generally wouldn't be as long as before. The other types of bridge and alternatives do however still remain open if it fails and can be progressed to if need be.
Fixed-fixed and fixed-movable are both very reliable bridges and have excellent long- term outcomes. They are both most consistent and predictable.
Dentists will have treated cases similar to yours before, (although not exactly the same). They will therefore have a good idea as to what is most likely to work in your given situation and they can share their experiences to help you make a decision.
If a patient asked for a particular type of bridge and I felt it wouldn’t work, or was not in their best interests, then I would politely say- "No!" If I felt that it might work, I would just need to make sure they understood the limitations of that option, even if it was not the choice I would have made!
Whatever work you have done at the dentist, your bite is a key factor in its success. You can bite on a fixed- fixed bridge as you would normally, but a resin-retained bridge-bridge would need to be kept out of the bite, if it was to stand any real chance of lasting. You would also need to be careful when biting and chewing hard foods.
The cost of the bridge
may also narrow down or dictate your options, including reconsidering a partial denture
, until you have saved enough money for a bridge or implant if that's what you decide to do.