Palatal displacement of canines and maxillary skeletal width.

Introduction: The purpose of this study was to determine whether a clinically significant association exists between maxillary skeletal width and palatal canine impaction, also known as palatally displaced canine (PDC).
Methods: Seventy-nine patients with PDC were matched for age, sex, and malocclusion to 79 controls. Maxillary and mandibular skeletal widths and nasal cavity widths were measured on posteroanterior cephalograms; maxillary and mandibular intermolar widths were measured on dental casts; and maxillary interalveolar arch widths at 3 levels (canine, premolar, and first molar) were measured on occlusograms.
Results: Only maxillary alveolar arch width at the canine level was significantly different between the 2 groups. However, further analysis showed that the presence of erupted deciduous or permanent canines, rather than their absence in the canine area (whether due to extraction, exfoliation, impaction, or not yet having erupted), was strongly associated with maxillary intercanine alveolar arch width.
Conclusions: The additional finding in this study that the eruptive status of canines significantly affects maxillary alveolar arch width in this area suggests that maxillary intercanine alveolar arch width as measured in this or other studies is not a good predictor of PDC.