Timing of dental development in relation to the treatment of maxillary canines: a retrospective register-based study.

OBJECTIVE: To describe differences in the dental age of Finnish children with the mixed stage of dentition in relation to the treatment provided for the permanent maxillary canines. MATERIAL AND METHODS: This retrospective register-based study was based on 1,332 cross-sectional dental panoramic tomographs (DPTs) for children with a chronological age of 8.5-10.5 years together with longitudinal information on the eruption and treatment of 1,817 maxillary canines in the same children. The treatments were categorized into early (interceptive treatment and early headgear) and late treatment (orthodontic treatment and treatment for crowding) groups. Dental age was assessed by Demirjian's dental maturity method and grouped into delayed (≤ -1 year), normal (> -1 and < +1), and advanced (≥ +1 year) relative to children's chronological age. Results were performed using Pearson's chi-square test, Fisher's exact test, and multinominal logistic regression models. RESULTS: Normal dental age at the time of the DPT was detected most often in the children in all studied treatment groups. Delayed dental age was detected more often in the children in the early treatment group and advanced dental age in the late treatment group (p = 0.002). The mean dental age of the girls with early treated canine(s) lagged significantly behind that of the girls in the groups that received no treatment (-0.43 years, p = 0.004) or late treatment (-0.45 years, p = 0.026). Delayed dental age was detected in 28.1% of the interceptively treated canines, leading to an association between delayed dental age and interceptive treatment (odds ratio 3.99, 95% confidence interval 1.84-8.67). CONCLUSIONS: Association was found between delayed dental age and interceptive treatment of a maxillary canine. Because of variations in dental age within the same age group, the timing of treatment plays a key role in order to achieve early treatment options for children's erupting maxillary canines.