Composite Resin YES - Silver-Mercury NO

One of the most common questions asked in our practice concerns our choice of the material that we use to restore cavities.

Silver-mercury (amalgam) fillings were introduced to dentistry over 100 years ago. At the time, this mixture of silver and mercury was considered a miracle material (of course, at that time, so was indoor plumbing). Today, amalgam fillings are made of a mixture of silver/tin/copper alloy and mercury in about 50/50 proportions. And as of today the American Dental Association believes that amalgam is a safe and effective material for use in the human mouth. They are entitled to their opinion. Here is my personal opinion about amalgam:

It is possible that the mercury in amalgam is not harmful to us. However, mercury is a toxic substance and according to the EPA, must be disposed of in a Toxic Waste Disposal Site. In my opinion, anything that must be disposed of in a Toxic Waste Disposal Site should maybe not be placed in our mouths. But this may simply be an over-cautious position on my part. I do not actually know what the long term outcome of on-going research will be. I do know that some European countries and a couple of states in the U.S. have regulated amalgam use, mostly because of environmental contamination reasons. Some European countries have banned the use of amalgam in pregnant women and young children.

I want to be clear on this. I have not used amalgam since April of 1982. And the reason has nothing to do with its safety or non-safety. The jury is still out on that.

The reason I do not use amalgam is that, in my opinion, it is a poor restorative material compared to newer materials we have now. Like everything else, improvements have been constant over the last 100 years. It took science until the 70’s to develop an alternative to amalgam, and into the early 90’s to perfect it to its current level.

The material I favor and use as my first choice is bonded composite resin. This material is extremely biocompatible and flexes and wears like natural teeth. A silver-mercury restoration has no bond to tooth structure. Expansion and contraction of this material over the years causes cracks in teeth and eventually, many teeth will fracture. You may have had this happen to you, even when you were eating something soft. Amalgam tends to leak after five or ten years, causing recurrent decay. Amalgam corrodes and turns black.

There is no way I will ever place amalgam in a patient’s mouth again.

When aging amalgam restorations are replaced by bonded composite resin restorations, the strength of the tooth is increased and underlining tooth structure is sealed.

Plus, of course, composite resin restorations are tooth colored and are so much more attractive and natural looking than metal fillings.

Now let me talk with you about the economics of composite resin. Composite resin restorations are more technique sensitive and are more time consuming to place. Special care must be exercised to operate in a controlled environment that can be moist when desired and dry when desired. Composite resin is more sensitive to moisture control procedures than amalgam. When placing composite resin fillings, we seal the dentin against bacterial infiltration and protect the dental pulp from irritation. As a result of this necessary expertise and the increased time associated with composite placement, the cost of restoring teeth with composite resin is a little higher than with amalgam.

Insurance companies are slow to embrace new techniques, especially when it could cost them money to provide state-of-the-art care to their insured. Many insurance companies will only cover the cheapest material to restore teeth. That’s amalgam, and many will pay their amalgam benefit even when composite resin is used. Yes, they are allowed to do that.

My patients have mostly learned about the ways insurance carriers pay benefits. For example, they have learned not to be fooled by the “usual and customary fee” jive and they know that this is bogus and is intended to drive a wedge between patient and doctor. If you are concerned about anything you read in an Explanation of Benefits you receive, just call. We’ll explain it with straight, honest talk. You don't have to be my patient to get advice; we'll be glad to help you.

Composite resin is one of a wonderful list of modern, state-of-the-art beautiful materials dentists use to help you have the strong, functional teeth and great smile you have always wanted.

You can post a comment or ask a question by clicking on the word "comments" right below this post.

What is the difference between crowns, inlays and fillings?

This is one of the most asked questions I get at the chair. So here’s a summary answer.

Crowns. People usually call crowns “caps”. Think of a crown as a kind of perfectly formed tooth-shaped thimble that fits over the whole tooth and covers it completely. It’s the strongest restoration we have, and it can repair teeth when nothing else will work. It can be gold, porcelain, plastic, or any combination. It can be made to look, feel, and function naturally. It can be attached to other restorations to form bridges and stabilizing splints. We need to shape your tooth to fit under the crown.

Inlays (and onlays). Think of inlays as very strong fillings for teeth that are too badly damaged for an ordinary filling but not so badly damaged so they need a crown. Inlays are made outside the mouth on an exact replica of your tooth and then placed into your tooth and bonded there. Inlays come in two basic forms: inlays and onlays. Inlays fit completely into a prepared tooth, while onlays fit into the tooth but roll over the top and cover one or more cusps to protect them from fracture. A big advantage of inlays and onlays is that they can be fashioned with near perfect form, because they are made outside the mouth. And because of the way they are made, they are very resistant to breakage. They are the best way to restore form and function to any tooth while preserving as much natural tooth structure as possible.

Inlays and onlays can be gold, porcelain, or composite resin.

Since they are made in the laboratory on a model of your teeth made from impressions, like crowns they need two visits to complete.

Composite resin onlays can sometimes be made right in the natural tooth instead of on a model. This restoration, which we call an “direct resin onlay”, is a one visit procedure, and is becoming more and more popular as the resin manufacturers give us increasingly great resin materials. I am liking doing these more and more. They save you some time and they save you some money.

Fillings. This is what dentists usually are talking about when they mean a restoration fashioned right in your tooth using soft materials that harden in the tooth, while you sit with your mouth open. In our office they are made of composite resin (hardened by the high-intensity blue light you’ve seen us use so often). We do not use silver amalgam for fillings. We gave amalgam up in 1982 (yup, 1982).

Fillings are one-visit procedures, and are an excellent choice for small to moderate repairs to teeth that are still strong. Modern composite resins are amazingly good materials, and getting better and better all the time. If the damage to your tooth is too extensive for a good resin filling, the tooth should be restored with an inlay, onlay, or crown.

The choice of restorative technique depends on many factors, and is made with you at the time. As one patient said while we were making this choice with him, “You got to fit the punishment to the crime.”

Not the way I would have said it, but it does express the idea pretty well.

Send me e-mail at DrSteveRoss@aol.com if you have a question and you want a personal answer.