Aim: The aim of this retrospective trial was to investigate differences in mesiodistal and vestibulo-oral crown sizes of naturally, fully-erupted permanent maxillary teeth between patients with and without palatal canine displacement.
Patients and method: 115 patients (mean age: 14 years 10 months; females: 77 males: 38) treated in the Department of Orthodontics, University of Munich were included in the study. 65 of the patients showed at least one palatally-displaced canine. Diagnosis and the location of the displacement were determined on the basis of standardized radiographs and confirmed by surgical documentation. Each maxillary tooth's mesiodistal and vestibulo-oral width was measured using a dial caliper on each dental cast. Excluded were partially-erupted teeth and surfaces with caries or restorations that had to be measured. An analysis of available space was made by evaluating the pre-treatment dental casts of all patients included in the study.
Results: Comparing the tooth widths of patients with unilateral canine displacement with the corresponding contralateral quadrants, we noted a statistically significant difference, namely that the central and lateral incisors and the canines of the affected side were narrower than those of the non-affected side in the same patient. Moreover, the displaced upper canines showed an increase in vestibulo-oral dimension. Overall tooth width (including all tooth groups) in patients with palatally-displaced canines was significantly less than that in the control group. However, when comparing the crown diameters of unilaterally- and bilaterally-affected patients, no differences in tooth-size were observed. The space-analysis showed excessive dental-arch space in patients with a palatally-displaced canine.
Conclusion: Patients affected by palatal canine displacement showed significantly smaller maxillary tooth size.