Sometimes a white filling can be sensitive to cold or biting after being placed. This is not an often occurrence. However, one cause of this discomfort is that the filling was very large and close to the nerve. In this instance, the tooth could get better with time or could not improve and need a root canal. Another factor that could cause tooth pain is if the bite of the new filling is too high. This can occur if the patient is extremely numb and unable to reproduce their normal bite during treatment. This just requires a quick adjustment to the filling. It is important to have the filling adjusted because it will not wear down on its own.