Hi. It could be a periodontitis affecting gums. This is a silent problem which is usually experienced as a loose tooth in later years. Visit dentist for best possible solution. Regards

Hello. . There can be multiple reasons for this kind of a problem. Most common is accidentally biting on something hard. But to zero in on the cause of the problem, a check up is necessary. So I would suggest that you visit a dentist for a thorough check up and the necessary treatment which can be decided only after clinical examination. Take care.