Incidence of apical root resorption in segmental canine retraction using friction and frictionless mechanics

Aim: To evaluate the incidence and amount of periapical root resorption of maxillary and mandibular canines during fixed orthodontic treatment using friction and frictionless mechanics. Materials and Methods: The study population included patients aged in between 14 to 20 years undergoing orthodontic treatments in the Dept. Of Orthodontics and Dentofacial Orthopaedics. Twenty samples were selected by convenience sampling method and were divided into two groups namely, Group A (n=10): Segmental canine retraction using frictionless mechanics .Group B (n=10): Segmental canine retraction using friction mechanics. The group A and B patients underwent first pre molar extraction, 0.022 MBT brackets were bonded. The pre retraction radiographs and post retraction radiographs of maxillary and mandibular canines was obtained by standardized technique and external apical root resorption was evaluated using SOREDEX DIGORA imaging software. Result: The between group comparision i.e pre retraction and post retraction of frictionless mechanics and friction mechanics showed Z value of -1.250 and P value of 0.211 for pre retraction values and Z value of -1.402 and P value of 0.161 for post retraction values. The comparison of pre retraction values of two groups showed there is no statistically significant difference between two groups and hence they can be compared after intervention. The comparison of post retraction values of two groups showed there is no statistically significant difference between two groups. In within the group comparison the mean difference, Z value and P value of frictionless mechanism is 0.5, 0.00 and 1.00 respectively. The mean difference, Z value and P value of friction mechanism is 0.5, -1.0 and 0.310 respectively. Conclusion: Segmental canine retraction using friction and frictionless mechanics produces the same amount of apical root resorption.