Fusion

So one of these teeth is not like the other..... What is it?? Fusion of the mandibular right lateral incisor and canine (QR fusion). This picture is of my cousin's little girl. My cousin came up to me at a family party and said, "Look at her teeth, I can't floss between them!" I was excited the moment I saw it because I had just had a course on dental anomalies and I knew what it was. It is pretty cool when you are a first year dental student and you get opportunities to apply what you learned in the class room to a more clinical setting. Street Cred....

Anyways, "Fusion" is the union of two tooth buds during their development way before the teeth poke through the gums. You can see in the image how it appears the lateral incisor and the canine kind of grew into each other during development. This should not be confused for "gemination" which is when a tooth bud partially splits during development resulting in a large/wide tooth, frequently with a vertical line running inciso-apically. The two anomalies can look very similar. To determine if it is gemination or fusion, you need to know how many teeth should be in the mouth, you can tell how there should be a canine and a lateral incisor between that molar and the central incisor. This tells us that two teeth merged. Pretty cool huh? Well I ran this photo by a professor at school and he did not think there were any implications of abnormalities that would present in the permanent dentition. In otherwords, she'll lose the tooth, permanent teeth will grow in and everything should be good. So the real question is when she looses the tooth, does she get double payment from the tooth fairy? You decide...