Feb 9, 2016 Hey. My gums were also tender and swollen for about a week. I was wondering if having a really overactive thyroid would cause these problems. I should also tell you that my doctor is very worried that I could have a heart attack at any moment. I sometimes feel dizzy, can not sleep, always hungry, losing weight fast, some days my eyes are sore, and my vision is also blurred. Can hypothyroidism cause tooth decay? I would like to hear some suggestions and advice before visiting my dentist in Burlington, Pearl Dental. I am concerned I brush two times a day now and my teeth are still getting worse.