Evaluation of the mandibular arch in patients with impacted permanent lower canines.

Aim: To determine the features of the mandibular dental arch in subjects presenting with impacted permanent lower canines.

Methods: The 'impaction group' consisted of 48 Indian subjects with mandibular canine impaction (Females:Males, 1.5:1; mean age, 15.03 ± 0.49 years). The 'control group' was comprised of 96 age-, gender- and malocclusion-matched Indians who were randomly selected from subjects initially screened but who had completely erupted mandibular canines. Arch width, arch length, arch shape and space status (total tooth size, arch-length--tooth-size discrepancy) were assessed using dental models and were compared between the groups using comparative measurements and statistics.

Results: Statistically significant differences were demonstrated with respect to the arch length, arch shape, total tooth size and arch-length--tooth-size discrepancy (p = 0.03, 0.02, 0.04, 0.01; independent 2-sample t-tests, respectively). Crowding was more prevalent in subjects with impaction than in the controls, with the difference being statistically significant (chi-square = 13.202; degrees of freedom (df) = 4; p = 0.010).

Conclusion: Patients with permanent mandibular canine impaction have adequately wide but shorter lower dental arch forms along with wider mandibular total tooth size and greater arch-length--tooth-size discrepancy when compared with a control sample.