Tooth-size reduction associated with occurrence of palatal displacement ofcanines

This study investigates mesiodistal crown size of the maxillary and mandibu lar incisors of patients with palatally displaced canines (PDC). Pretreatme nt dental casts of orthodontic patients with PDC of 1 or both maxillary can ines (N = 31; M10:F21) were collected. This PDC sample was matched accordin g to age and sex with pretreatment dental casts from unaffected orthodontic patients. For the PDC and matched control samples, maximum mesiodistal cro wn diameters were recorded for the 4 incisors on the left side only. The re sults showed that, on average, the mesiodistal crown diameters for the maxi llary and mandibular incisors measured smaller in the PDC sample than in th e control sample. These findings of statistically significant tooth-size re ductions associated with PDC occurrence indicate a generalized pattern of r educed tooth size as a characteristic associated with the PDC anomaly. Furt her, the presence of generalized tooth-size reduction in cases with palatal ly displaced canines helps explain why most orthodontic treatment plans for PDC patients are of the nonextraction type.