RESUMEN
OBJECTIVE: The aim of this study was to determine the relationship between the status of a unilateral palatally impacted maxillary canine (as seen on the panoramic radiograph) and the orthodontic treatment duration. METHODS: A total of 36 subjects were chosen (8 males and 28 females, 13.7 +/- 2.5 years). All patients had undergone orthodontic traction of the impacted canine after a closed flap surgery. The position of impacted canine on the panoramic radiograph was traced and calculated with regard to the treatment duration. RESULTS: The canine overlap over the lateral incisor (COGr) had significant statistical difference between the short-term and the long-term treatment duration groups (divided by average treatment time of 21 months) (p < 0.05). Multiple regression indicated that the variables of significance (with treatment duration as the dependent variable) were the canine vertical height from the occlusal plane (HCV, r(2) = 0.115; p < 0.05) and the mandibular anterior width (MnDW, r(2) = 0.142; p < 0.05). The treatment duration, the canine angle to the incisor midline (CA), and HCV decreased from primary dentition (under 12 yrs) to permanent dentition (15 yrs). Howerer, these increased again at the adolescent ages (over 16 yrs). CONCLUSION: These findings suggested that orthodontic treatment of a palatally impacted canine would show good prognosis at an age of early permanent dentition with the canine showing smaller CA and HCV.