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A composite filling could be contaminated with saliva. This would weaken the bond between the filling and the tooth and allow for leaks. Other times, there may be small gaps where the tooth and filling meet. These gaps are caused by shrinkage when your dentist
places the filling. Sensitivity after receiving a composite filling may disappear over time. If it doesn't, the filling may need to be replaced.
Fillings also can leak as a result of wear over time. These fillings should be replaced.
Clenching or grinding also can cause your teeth and fillings to crack or develop small craze lines.
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