A filling can crack when it is old, large or it has too much biting pressure on it. It can also crack if the tooth structure under the filling has softened.
People who have previously broken teeth or fillings may be more likely to break them in the future. Other factors that can increase the risk of cracked or broken fillings are: The presence of older and larger fillings. People who grind their teeth or have strong chewing muscles. People who have uneven or unbalanced bites. People who have destructive habits, such as chewing ice or opening things with their teeth.
Your dentist will make recommendations to minimize your risk of a cracked filling. Here are some things that may be recommended: Replace older fillings before they break. Place a dental cap or “crown” over very large fillings to protect them. Have your bite adjusted if it is unbalanced. Wear a night-time grinding appliance. Do not chew ice or use your teeth to open things.
Bacteria can get into cracks in a filling and lead to decay under the filling material. This decay can rapidly progress into the nerve of your tooth causing a vital abscess. When this happens, the tooth requires root canal treatment or extraction to address the infection.