Dental fillings are the best solution for cavities available to a dentist but no solution is quite perfect. Whether made from a composite resin or silver amalgam, a filling will have to be replaced at some point in time for a number of reasons including:

– Damage – Grinding teeth or chewing hard substances can chip or damage fillings

– Size – A large filling has less tooth structure for support and may loosen or fall out

– Age – Normal wear and tear will eventually erode and loosen the filling

Regular checks will help but “no dental filling material lasts forever” and you can find out more at https://yourdentalhealthresource.com/can-cavities-form-under-dental-fillings/