Year : 2020

Volume : Volume 11

Issue : Issue 2s

Abstract

Background:  Objectives: To evaluate the effects of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced tooth root resorption caused by torque in human subjects. Materials and Methods: Ten healthy patients (12–35 years of age) who required extraction of all first premolars as a part of their routine orthodontic treatment were recruited. A 15u twist was applied in the arch wire using 0.019 3 0.025-inch TMA in a 0.022-inch bracket system (Synergy R) that produced a buccal root torque of approximately 5 N/mm at the bracket level. Using a split mouth design, randomization, and blinding, one side of the arch received LIPUS for 20 minutes per day for 4 weeks at an incident intensity of 30 mW/cm2 of the transducers’ surface area. The other side served as a self-control, which received a sham transducer. After 4 weeks, all first premolars were extracted and micro–computed tomographic analysis was performed on these extracted teeth. A linear mixed-model statistical analysis was used. Results: LIPUS-treated teeth showed significantly less total volume of resorption lacunae compared to control teeth by a mean difference of (0.54 6 0.09 mm3) (P , .001) and percentage of root resorption by a mean difference of (0.33 6 0.05 mm3) (P , .001). In addition, significantly fewer resorption lacunae were found on all root surfaces in the LIPUS group compared to the control except in the instance of the distal surface. Conclusions: LIPUS minimizes root resorption when applied during torque tooth movement over a 4-week period.

Keywords: Orthodontic root resorption; Torque; Low-intensity pulsed ultrasound; LIPUS.