Bonded fillings for back teeth. / Factors to consider.

When is it an acceptable choice?

Dental composite (the plastic compound used with tooth-bonding technique) is not always an appropriate restorative to use to make fillings for back teeth.

Your dentist will need to take the following factors into consideration before they can decide that it makes a suitable choice for your tooth.

A) Size limitations.

Dental composite fillings do not have the combined strength and wear characteristics that dental amalgam fillings or other types of dental restorations do. And for this reason most dentists would probably feel that dental bonding is best suited for use in those circumstances where the filling being placed is somewhat on the small or conservative side.

One school of thought is that the width of a composite filling should be less than about one third of the distance between the tooth's cusps. And no tooth to filling junctions should lie at that point where the cusps of opposing teeth strike.

If the planned restoration does not conform to these guidelines, and especially in those cases where the dental bonding will be used to rebuild entire tooth cusps, you and your dentist may still decide to place a dental composite restoration but the longevity of the filling might be expected to be comparatively compromised.

B) Will the filling placed be strong enough?

Dental composite fillings do not have the pronounced wear and strength characteristics that many other types of dental restorations do. In those situations where a dental patient is known to clench or grind their teeth (dentists call this activity "bruxism"), most dentists would probably not consider a composite filling to be the best choice. Bruxing habits can easily subject composite fillings to forces that exceed the limitations of their physical properties and therefore result in premature failure.

C) Does the patient have any known metal allergies?

While rare, people can have allergic reactions to some of the metals dentists use to create dental restorations. In these situations dental composite may be (out of necessity) the dental restorative that is chosen. (In the dental literature there are fewer than 100 documented cases of localized allergic reactions associated with the use of dental amalgam.)

D) Does the patient want to avoid the use of amalgam?

One of the components of dental amalgam is mercury. Over the past few decades there has been some debate (more so in the popular press than in bona fide dental research publications) as to the ill effects of this mercury content on a person's health.

In defense of dental amalgam, we would like to bring to your attention that dental amalgam has been in use in dentistry for more than 150 years. During this time period literally billions of amalgam fillings have been placed. One would anticipate that if a problem did exist that by now there would be ample epidemiological evidence demonstrating any ill effects caused by dental amalgam on the health of dental patients (or on the health of the dentists who work with this metal every day). To the contrary, however, there is not. In the time frame of the last two decades (a time period during which the popular press has hyped this topic and a time frame during which you would expect that any and all peer reviewed scientific studies identifying any problems associated with dental amalgam would be pushed rapidly to the forefront) no ground swell of dental research has demonstrated a health problem associated with the mercury found in amalgam fillings.

Several national and international health organizations have reviewed the available literature evaluating health concerns associated with the use of dental amalgam. None of the following organizations have found a demonstrable risk associated with the use of dental amalgam: U.S. Public Health Service, The American Dental Association, Food and Drug Administration, World Health Organization, FDI World Dental Federation.

However, in those cases where a person has for whatever reason decided that they do not want to have their teeth restored with dental amalgam, then a composite filling may be chosen out of necessity.

E) How much will the filling show?

Since white fillings created using dental bonding can mimic the color of tooth structure, whereas fillings made from dental amalgam clearly cannot, many people prefer that their dentist place composite fillings. And in those cases where either type of filling material can provide a satisfactory alternative, the white color of a composite filling can make it an easy choice for the patient.

There can be other concerns associated with cosmetic appearances other than just the direct visualization of the filling itself. Dental amalgam fillings can, at times, show through (or with time even cause staining of) the tooth structure that surrounds them. As a consequence, even though the filling itself may not be readily visualized another untreated portion of the tooth can take on a grayish tint. In many cases this may not be much of a cosmetic concern but some back teeth (especially upper ones) can show prominently when a person smiles. If this is the case then placing a white composite filling might prove to be a good choice. You simply need to ask your dentist and let them advise you on this issue.

Bonded fillings for back teeth is a relatively new dental technique.

Whereas the use of dental amalgam (the metal dentist use to create "silver" fillings) can be traced back for more than 150 years, the routine use of dental composite (bonding) in back teeth has a history of only about two decades.

Composite restorative was first put into widespread use by dentists in the 1960's. But at that time it was not recommended that it be used to create fillings for back teeth. That's because the products of that era had relatively poor strength and wear properties.

Those back fillings that were attempted in typically deteriorated in a relatively short time frame because the materials used to make them could not withstand the forces they were subjected to.

Of course, since the 1960's dental composites have under gone significant change and improvement. As a result, nowadays it's fairly commonplace that a dentist might suggest the use bonding to create white fillings for a patient's back teeth.