Going to the dentist and getting a filling is a common experience for most of us, but not all of these experiences are the same.
When bacteria (that are ever present in our mouths) are allowed to rest, undisturbed, against the surface of our teeth, their metabolic byproducts (their poop!) can start to damage and weaken our teeth, more specifically, the enamel and dentin. The excavation, or removal, of the damaged tooth structure produces a hole (a cavity) in the tooth that now needs to be returned to its original form and function.
Now, I can choose from several materials to fill the hole we created. One of the traditional materials used is dental amalgam. These are your typical silver or metal fillings and are compromised of 50% mercury (!) and 50% other metals (typically silver, copper, tin, etc., but each product has their own specific combination). While the material is low cost, durable, and easy to place, it has a high mercury content which can be worrisome. In addition, dental amalgam is not bonded to the tooth, it is simply mechanically retained in the tooth. (Imagine putting your hand in the cookie jar, grabbing the cookie, and then not being able to get your hand out!!). The “hole” made in the tooth is made wider in its deepest portion and narrower at the top so that when the material sets, it is “locked” into the tooth.
This is good (the filling stays in), but it also has the drawback of making the tooth weaker overall. The bigger the filling, the weaker the tooth!
Another alternative, and the one most commonly used on a daily basis at the clinic to restore teeth directly, is a white, composite material. Basically a plastic material compromised of different sized particles of resin (or plastic) found together in a mixture of other smaller particles. Not only can the material be matched to your tooth colour, but the science of the insertion into the hole allows us to bond (on stick!) the filling to the tooth. Wow! This not only allows us to make a smaller hole, but it also reduces the amount of microleakage the filling will suffer over time.
All dental materials “leak”. From the moment we put any material in the tooth, the bacteria in your mouth are trying to get back in! Microleakage has been studied right alongside all the other risks and benefits of a given material prior to entering your mouth. These white, composite fillings not only allow us to be more conservative with the removal of tooth structure, but also enable us to seal the tooth as best we can. It is a great material that continues to improve (I think we’re up to the 9th generation of bonding materials) and has applications for 8-80 year olds from the repair of “baby teeth” to the “at risk” tooth surfaces of seniors.