Hello there ...the picture is not clear to comment anything....visit a nearby dentist for proper diagnosis and plan the treatment accordingly.. Take care ...!!

Hi..it is a cavity. You might require either a filling or root canal based on x ray. Regards

This might be decayed cavity on the root surface of the tooth ,get an x ray done to access the depth of the cavity and acvordingly treatment can be planned

Hello, The picture is not very clear. According to what i can see is it looks like a dental decay to me. You need to visit a dentist and get it evaluated. If it is deep you need to get and X-ray and get it evaluated. If it is not very deep you should get the decay removed and get a composite filling done. If it is very deep and has reached the nerves of your teeth then you should get a root canal done of the tooth. In order to avoid a root canal please do not delay visiting a dentist and getting it treated ASAP. Hope it was helpful to you. Regards, Benchmark Dental Clinic.

The picture is not very clear it can be a cavity or tartar deposit on your teeth..if it is a cavity it would require a filling and if tartar a thorough scaling would solve your problem..