We often see patients with cracked teeth. Did you ever wonder what might be the cause? When growing up if we had a cavity most of us received an amalgam (silver-mercury) filling to restore it. Amalgam (silver-mercury) fillings were common. The problem with silver-mercury fillings is what they are made of and how they are used to fill a tooth. Usually the decayed area of the tooth is removed leaving a “hole” behind. Silver-mercury filling material is them mixed and placed in the hole. No adhesive is used so there is no seal provided to the tooth. Without a seal, saliva and other materials can slowly leak under and around the edges of the filling. As this occurs over time slowly the tooth can get a new cavity deep underneath the filling. This new decay can go undetected for years not being seen through the tooth or even visible in an x-ray until it is too late. When chewing on the tooth suddenly the silver filling can shift causing the tooth to crack. Also, once you realize that silver-mercury fillings are made up of 50% mercury you can understand how they crack teeth. What happens to mercury in a thermometer on a cold or hot day? It expands and contracts depending on the temperature. Well, silver-mercury fillings do the same thing when we eat something hot or cold. They also expand or contract 6 times more that the tooth. Expansion and contraction of the silver-mercury filling inside the tooth pushes against the parts of the tooth eventually causing it to break. We often recommend removing silver-mercury fillings for these reasons. A variety of other options such as, porcelain restorations, gold restorations and composite restorations are available to restore your tooth to its natural strength and appearance.