Recently I was giving a second opinion for an 8-year-old boy who presented with one upper central incisor in crossbite meaning it was behind the lower teeth when the bite was closed. Another orthodontist had recommended treatment for the crossbite. I strongly suspected that there were other problems that had been overlooked. The mother confirmed my suspicion that the primary central incisor (front baby tooth) had failed to fall out in a timely fashion and the permanent central incisor came in behind the primary tooth. The tooth came in far enough behind that every time this boy would bite down one permanent front tooth went in front of the lower teeth but the other permanent front tooth went behind the lower teeth. This was indeed an example where a tooth out of position was a red-flag warning. We can easily correct the crossbite of the central incisor, but that isn’t the point.
The larger story here is that keeping one primary tooth too long (over-retention) can frequently be a red flag warning that the other teeth may not fall out timely either. We recommended a CBCT x-ray. The roots of the upper primary lateral incisor teeth were not resorbing properly (not getting shorter) and both permanent laterals were headed into the roof of the mouth. They would ultimately come into the mouth too far back just like the central incisor. By having the primary lateral incisor teeth removed right away I fully expect the permanent laterals to erupt nicely into proper positions with no need for orthodontics. The story doesn’t end there, however.
We will now have this young man come into our office every few months to monitor him very closely. A study I did in 1974 found that over-retention of teeth was a big factor when it comes to having permanent cuspid teeth become impacted (eye teeth in the roof of the mouth and not coming down). When I did the study the incidence of reported cuspid impaction was in 2-3% of all cases. This may seem like a small number, but the damage impacted cuspids can do is not small at all! Serious root damage to the adjacent lateral and/or central incisors or loss of those teeth is a possible consequence we identified in the study.
We want to make sure this boy’s primary cuspid teeth (baby eye teeth) don’t stay too long and deflect the permanent cuspids into the roof of the mouth where they could do a lot of damage. A few visits to our office, an occasional x-ray, and being sure primary (baby) teeth come out when they may very well keep this young man from ever having braces!
I love preventing problems rather than treating them.