Age and gender differences in maxillary canine impaction severity and orthodontic treatment difficulty – A retrospective cross-sectional study

The objectives of this study were to compare the maxillary canine impaction severity and orthodontic treatment difficulty in relation to age and gender. Orthopantomograms of 105 patients with maxillary canine impaction were retrospectively collected and divided into 50 adolescents (11–17 years; 30% females) and 55 young adults (18–25 years; 34% females). Canine impaction severity was determined using one angular and three linear radiographic measurements, while orthodontic treatment difficulty was determined using a modified Pitt et al. index. Age and gender differences were assessed using Chi-square with Bonferroni correction and Mann–Whitney U-tests (P < 0.05), while the association between orthodontic treatment difficulty index score and age was assessed using linear regression analysis (95% confidence interval). Compared to young adults, adolescents had mild (<30°) canine long axis to midline angulation (P = 0.008) and distally positioned cusp tip of impacted canine relative to adjacent lateral incisor root (P < 0.001). Meanwhile, males compared to females had distally positioned cusp tip of impacted canine relative to adjacent lateral incisor root (P = 0.008), while females compared to males had the canine cusp tip mesial to lateral incisor root (P = 0.002). The orthodontic treatment difficulty trend increased with age (R2 = 0.077; P < 001) and was higher in young adults than adolescents (P = 0.0218). The severity of maxillary canine impaction was higher in young adults and, to a lesser extent, in females. Orthodontic treatment difficulty of impacted maxillary canines also increased with age but not gender.