My boyfriend had 2 of his wisdom teeth taken out approx. 2 years ago. His dentist told him at the time that he only had 3 (the third is still in his mouth) and that the 4th one, if it hasn't come in yet it wont be coming in at all. He has a sort of hole with something white inside which looks to me like a tooth coming in. This is located where the 4th tooth was "supposed" to be. He no longer has dental insurance and I am convinced it's the last wisdom tooth but he claims it's an ulcer or something along that line. Could this possibly be his 4th wisdom tooth? He is currently 22 years old.