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CROWNS, IMPLANTS, TOOTH BRIDGES
tooth bridges, dentist bridges, dentist implants, dentist crowns
Replacing Missing Teeth
Picture courtesy of Stephen F. Gordon, 1993
Usually done in two appointments, the preparation appointment, then the seating appointment. The crown will be made on a model in a LAB (this is the reason for the 2 appointments). Some dental offices have CEREC milling machines, in which case your crown can be done in a single visit. This is not available in the majority of dental offices at this time, although the technology points towards this in the future. Teeth are crowned for a number of reasons... most often being because of INSUFFICIENT TOOTH STRUCTURE.
When a tooth BREAKS, IF there is not enough tooth structure to SUPPORT A FILLING, you may need a crown. HOW MUCH TOOTH IS NOT ENOUGH?? In POSTERIOR teeth (in the back), if part of it fractures, a crown would be the next logical step. Large fillings can sometimes be placed, but if the tooth has fractured once already, most likely if you put a larger filling in a tooth, it will fracture again.
WHY ELSE are teeth crowned?? Many dentists will have you believe that teeth NEED to be crowned to PREVENT fracture. This IS TRUE in BACK TEETH that have had ROOT CANALS done. Large amalgam fillings can cause fractures in teeth over time. More and more dental offices are equipped with intraoral cameras (cameras which take pictures of your teeth from inside your mouth), and it is very common to see fracture lines on teeth with large amalgams. Once the dentist can detect the fracture with his or her instruments, it is likely that that tooth will fracture at some point. Doing a crown can prevent that from happening. Yes, crowns are expensive, but if it is not done and the tooth fractures, it is possible that that tooth may be lost, or need to be root canaled , or even extracted . Both of which would be much more expensive than that single crown.
Patients who have bad PERIODONTAL DISEASE may not be the ideal situation to place a crown, but if the tooth is going to break without one, just be aware that your tooth is compromised so the long term prognosis is decreased. If you CLENCH OR GRIND YOUR TEETH , you are more likely to FRACTURE teeth. So crowns MAY BE necessary.
IS IT POSSIBLE TO PREDICT WHICH TEETH WILL FRACTURE AND WHEN?? Unfortunately not, but if there are existing fractures in a tooth, it is like playing Russian Roulette with your teeth. CROWNS can be GOLD, PROCELAIN, or PORCELAIN FUSED TO GOLD/METAL (PFM/PFG). WHY GOLD? The hardness of gold is very close to natural tooth hardness, therefore it does not wear against the opposing tooth. PORCELAIN is much harder than natural tooth structure, therefore can wear down the opposing tooth/teeth. WHY NOT GOLD? ESTHETICS. In the current day of everyone wanting whiter teeth and looking more natural, gold is esthetically less acceptable, unless it is in the back of your mouth. PORCELAIN vs PORCELAIN FUSED TO METAL? Like gold, the metal hardness is closer to that of natural tooth structure, so part of the tooth can be PORCELAIN (for esthetics) and part of it can be metal/gold (part that hits the opposing tooth). The metal is normally an alloy of gold, with the amount of gold and other metals varying depending on the type of crown. Because of the metal substructure, the esthetics of PFM crowns can be close to your natural tooth, but not normally as good as the following 2 options. LAVA CROWNS: Lava crowns are like PFM crowns, except the metal substructure is primarily cubic zirconia, which has a white appearance rather than a silver or gold appearance. This allows for much better esthetics, but may still not be suitable for all posterior teeth under high stress. WHY 100% PORCELAIN?? ESTHETICS. Full porcelain crowns look very good and natural, but they do not tend to hold up too well in the posterior region. In the anterior region, if they are not subjected to too much force, they should be ok.
After a crown is placed, the tooth still needs to be flossed and brushed, because it is still possible to get cavities under a crown. There are other issues that can arise after crown placement.
REPLACING MISSING TEETH: In general, there are 3 ways to replace your missing teeth.
Each area has POSITIVES and NEGATIVES. We’ll start at the top. Implants are a very good way to replace missing teeth. They function as individual teeth, and do not need to be supported by adjacent teeth. Basically what the procedure consists of is SCREW(S) surgically placed into your jaw bone, the bone is allowed to heal around the screw(s)- called osseointegration, and then a CROWN is attached to the screw!
They are also very VERSATILE, and can function alone, or can be used to anchor both FIXED and or REMOVABLE prosthetics. For example, below is an illustration of implants used to retain a lower partial denture.
Not all people can have implants. Patient selection and site (in the mouth) selection is very important.
Dental Implant Uses:
Implants bridges are NOT done from implant to natural tooth. Teeth have a periodontal ligament, which allow some (normally undetectable) movement, whereas implants do not move.
These are possible ways they do/can fail.
Fortunately, most of these can be avoided by proper placement and knowing their limitations.
TOOTH BRIDGES are multiple crowns fused together. For example, if you were missing one tooth, the teeth on either side of the space would be prepared for crowns, and 3 crowns fused together (the 2 anchor crowns plus the crown to fill the space) would be cemented into place.
The other drawback is that you are CROWNING teeth that may not necessarily NEED to be crowned. WHAT ARE THE RISKS OF CROWNING TEETH THAT DO NOT NEED TO BE CROWNED?? If the teeth have fillings on them already, probably not too much. If the teeth are UNCUT, there is a RISK of SENSITIVITY to elements such as HOT AND COLD, or even the possibility of ROOT CANAL THERAPY. It is UNLIKELY, but POSSIBLE.
The two (or more) teeth on either side of the space that are crowned, are called, abutments. Because these teeth are going to be assuming a heavier load from the missing tooth or teeth, the abutment teeth need to be very strong, and in good condition. If they have periodontal disease for example, that is not an ideal situation. THE PONTICS: The fake tooth that is going over the space where the missing tooth is, is called the pontic. If the tooth bridge is long span, there can be more than one pontics.
A bone graft is a surgical procedure where bone is added to an area to try and build up the ridge, in order to help support the teeth or provide better esthetics when trying to restore an area. When a tooth is removed, the gum and bone will normally shrink in that area. Sometimes a bone graft needs to be done during the extraction in order to preserve the bone from shrinking too much. Bone grafts can also be done as a seperate procedure.
This is a type of bridge that is usually only done in the front of the mouth., and to replace ONLY ONE tooth. Instead of putting full crowns on the two adjacent teeth, a false tooth is attached to two metal wings which are glued to the adjacent teeth. Because of the limited strength, they are not the best options for all patients. In those who grind or have inappropriate bites, MARYLAND BRIDGES will not be successful.
CANTILEVER BRIDGES:
This is sort of like holding a fishing pole over the water, in that you are holding the pole on one side but the tip/end of the pole is not supported by anything. Because it is not supported on both sides, the tooth that is supporting it on the one side, is overloaded, and this is not an ideal situation. On the other hand, there are some cases when this is acceptable.
tooth bridges, dentist bridges, dentist implants tooth bridges, dentist bridges, dentist implants
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