Just very recently I had a client with something I had never seen before affecting one of their upper lateral incisor teeth. The tooth had a developmental condition called an ‘invaginated odontome’. This is a rare condition where the surface of the tooth as it grows, folds in on itself to create an almost ‘pocket’ within the tooth. As this internal pocket is connected to the mouth through a very small opening it often leads to the death of the tooth shortly after it erupts and in many cases the formation of a root tip cyst (see the black area on the x ray below around the root tip). In the majority of cases to treat the tooth often leads to its unfortunate removal as conventional root canal treatment, due to the complex anatomy present is very likely to fail.
