Factors that relate to treatment duration for patients with palatally impacted maxillary canines

The objectives of this study were to determine the relationship between the initial position of a palatally impacted maxillary canine (as seen on a pa noramic radiograph) and the duration of orthodontic treatment and to determ ine whether a difference in treatment duration existed between patients wit h bilateral palatally impacted canines and patients with unilateral impacti on. A total of 47 adolescent subjects were chosen (9 subjects with unilater al impactions and 18 subjects with bilateral impactions). All subjects had full fixed orthodontic appliances placed. The treatment duration of this gr oup was compared with that of a control group with similar characteristics but without the impacted canine. The results showed that the average durati on of treatment was 22.4 months for the control group, 25.8 months for the unilateral-impacted group, and 32.3 months for the bilateral-impacted canin e group. The length of treatment for the impacted canine sample was related to the age of the patient at the start of treatment; younger patients requ ired a longer treatment. The younger the patient. the more severely impacte d the canine. The bilateral-impacted canine group had at least 1 canine tha t was more severely impacted than the impacted canine in the unilateral-imp acted group. If the canine was impacted less than 14 mm from the occlusal p lane, treatment duration averaged 23.8 months; if the canine was impacted m ore than 14 mm from the occlusal plane, treatment duration averaged 31.1 mo nths.