hi there, a recurrrent sore or white patch
in the mucosa could be due to the constant irritaion caused by the by the tooth. It would be a good idea to get the offending source removed because constant irritation can be one of the eitiological factor for malignancy. Do get an exfoliation cytology done of the site and that will help you rule out malignancy or even a biopsy
can be done to get over your worry. Take care.