Dental updates from Dr. Mckeever.

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"WHITE FILLING FAILURE"

Dentists are now placing more resin-based composites in posterior teeth (molars and bicuspids) than silver amalgams. I've gone through this before but it needs to be repeated because many, if not most, patients are not made aware of the difference in longevity of each of these materials.

For many years, resin-based composites have been used to restore cavities in the front (six) teeth and on the cheek side of posterior teeth. This type of filling material is esthetically pleasing and, if done correctly, can last a long time. And, this material has gotten stronger and better as time goes by. As the strength improves, more and more dentists have started placiing this type of restoration on the bitiing surfaces of the posterior teeth instead of the silver amalgam fillings many of us have had inserted over the years. This can be an O.K. procedure - I do some of these - but, it takes at least twice as long to fill a tooth with composite as it does with silver amalgam (making them more expensive to the patient).

When the longevity of these fillings was evaluated in a group of navy and marine recruits, the silver fillings won out hands down. Restoration longevity is critical to the military as well as to any other public health care system because a significant increase in the risk of failure could impose a substantial increase in overall treatment requirements and subsequent costs. Of even more importance to the military is the possibility of restoration failure during operational deployments which has been shown to be a significant problem in all services. Defective fillings accounted for 23 percent of all dental emergencies among U.S. Army personnel deployed to Bosnia in 2000 and 2001. Cavities and defective restorations accounted for 39 percent of all dental emergencies experienced byy Marines ashore during Operationn Desert Storm in 1990 and 1991. Military personned often are placed in hostile environents where dental care may not be available or is available only by traveling into potentially dangerous areas. For obvious reasons, minimizing the risks of such dental emergencies is paramount.

The main reason for the failure of most fillings is due to recurrent (new) decay especially under the gumline between the teeth. Dr. Karl Leinfelder, a noted dental materials expert, reported that amalgam restorations are expected to be clinically servicable for ten to twelve years while resin-based composites are expected to last only half that long. He states that one reason for the greater risk of secondary (new) decay in composites is their lack of bacteriostic (germ retardiing) elements such as the silver in dental amalgam. Not only is there no element to retard bacterial growth, but the constituents of resin-based composite actually may encourage the growth of these germs (germs, by the way, are the cause of cavities). This phenomanon is particularly destructive in patients that are highly susceptable to cavity formation. In the Marine study, this held true; the greater the risk of getting cavities the greater the risk of restoration re-treatment whether the teeth had been filled with composite or silver amalgam. However, there was a higher risk of replacement for resin-based composite restorations than for amalgam fillings.

This informations is not to discourage the placement of composite fillings because they can serve the patient quite well. However, the use of composite in patients that have a high caries rate should be discouraged. Some dentists do not use silver amalgam fillings any more because, for some reason, they have been convinced that composite materials will last longer. Since almost all studies that have been done on these two materials over the years have shown just the opposite, it does not serve the patients well for them not to be aware of the research and not to have a choice in the material selection especially since the composites cost quite a bit more.
posted by Steve at 3:57 PM