Clearly, some dentists aren’t. They are a tooth restoration with a proven track record. They last for a long time and they are simple, quick and inexpensive to place. If you’re working on back teeth that no one is going to see, why not just do silver fillings?
There’s certainly an argument to be made for that. Besides their metallic color, silver fillings have a couple other weaknesses.
strength only in bulk: Silver fillings are pretty strong, but there has to be a pretty big bulk of material. Anything less than about 2mm in depth or width is likely to fracture. This isn’t much of a problem if you have big spots of decay. But lets say you have a small cavity. The perfect example of this is a “groove cavity” in a back tooth. Often these cavities are relatively deep but very narrow. This narrowness doesn’t allow for the proper bulk of silver filling material. But it doesn’t make sense to widen the cavity for material. When you remove more tooth structure you actually weaken the tooth. There may not be problems in the first year, 5 years or even longer. But over time, a tooth weakened by removing extra tooth structure can crack and even break. Which could lead to pain and the need for more expensive dental work. Teeth can break for lots of reasons, but removing tooth structure to restore teeth is a common cause. As Dr. John Kois says, “the best dentistry is no dentistry.”
not bonded: in order to stay in a tooth silver fillings need to be placed into an undercut area. The material goes into a cavity in a soft, packable form and sets up hard. So when it’s placed into an undercut as a soft material and then hardens up, it stays in the tooth. This causes a similar problem, though. Often more tooth needs to be removed in order to make an undercut.
Modern bonded fillings use a chemical bond to stay in place. They are placed with a kind of “tooth glue” that doesn’t require removing any more tooth structure than what’s needed to clean out the tooth decay. In this way, bonded composite fillings can require less tooth structure to be removed. Which may result in a smaller likelyhood of tooth fracture down the road.
Dental amalgam has saved countless teeth over the more than 100 years it’s been in use. And it will continue to have a place in dentistry. It’s strong and cheap, but it’s ugly.
There are options that require the removal of less tooth structure that can be used as well. They look more like teeth and they are actually bonded to the tooth structure. They are MUCH more difficult to place well. They require much drier conditions and take a lot longer to place correctly. Bonded fillings are hands down my favorite restoration to place! When done with care they are beautiful and quite durable.
Questions or comments about this post? I’d be happy to answer them! Email me at firstname.lastname@example.org or call the office at (989) 799-9133. We would love to be your Saginaw dentist!
What’s the deal with silver fillings? Why is it that we see news stories every once in awhile questioning the safety of dental amalgam? The answer, in a nutshell, is Mercury.
The element Mercury (Hg) is highly toxic. Think broken thermometers and fluorescent light bulbs. Avoiding Mercury exposure is highly recommended. As an element, Mercury is poisonous.
Another element, Chlorine (Cl), is also highly toxic. Yet, when combined with the element Sodium (Na) you get a chemical that is common, safe and in reasonable doses, delicious. Common table salt is a chemical compound called Sodium chloride (NaCl) and is perfectly safe to eat in moderate amounts. But no one in their right mind would go out of their way to ingest Sodium or Chlorine on their own. The same goes for Mercury.
“Silver fillings” aren’t really fillings made of Silver. They are a combination of Mercury, Silver, Copper, Tin and other trace metals. Silver fillings are placed by thoroughly mixing these ingredients. The ingredients mix and form an alloy of the metals. This alloy is different than any of the ingredients individually. In other words, there isn’t just Mercury, Silver, Tin or Copper in there. It’s a whole new chemical compound made up of all of these metals. It’s kind of like concrete. You start with cement, sand, stone and water. The final product is concrete. You can’t go back and take the ingredients out of concrete without breaking down the concrete chemically.
The bottom line is that there’s no such thing as “Mercury fillings.” Dental amalgam has Mercury in it that is chemically combined with other metals to form an alloy. One of the properties of Mercury is it’s ability to form an alloy like this at room temperature.
Can dental amalgam “leak” Mercury? Yes. There can be a very slight release of mercury from amalgam fillings. A study conducted by measuring the Mercury vapor levels inside the mouth over a 24-hour period in patients with at least nine amalgam restorations showed the average daily dose of inhaled mercury vapor was 1.7 µg (micrograms), which is approximately only 1% of the threshold limit value of 300 to 500 µg/day established by the World Health Organization. So there is Mercury released from fillings, but it’s a very tiny amount.
What about Mercury exposure from dental amalgams causing diseases? The American Dental Association has weighed in regarding the safety and efficacy of dental amalgam. Scientific evidence concludes that the use of dental amalgam is safe. There is no evidence to support removing silver fillings in an effort to cure or prevent other diseases.
Dental amalgam has undoubtedly saved millions of teeth in its 100+ years of use. Until relatively recently there haven’t been inexpensive options to restore teeth that could hold a candle to silver fillings. They’re durable as heck and they’re relatively easy and inexpensive to place.
Are there any problems with dental amalgam? I actually see two.
They’re ugly. When polished they can be shiny and smooth, but they don’t look like a tooth. They look like metal, which they are.
In order to place a silver filling you need to remove a lot of tooth structure. In a tooth that’s never been filled before, this means that you’re cutting away more tooth structure than you need to.
To me, those are the main down sides to using dental amalgam. Perhaps these down sides deserve their own post (stay tuned!) I place very few dental amalgams any more because I’m confident that I can place an excellent bonded resin restoration (a.k.a: composite) in any situation that I might have used amalgam.
But my reasons for using composite fillings has nothing to do with Mercury. In my mind, the Mercury is a non-issue.