Influence of Low-level Laser Therapy on Stability and Displacement of Orthodontic Miniscrew Implants

The aim of this study is to evaluate the effect of Low level laser therapy (LLLT) on stability and displacement of orthodontic miniscrew implants with mediate and immediate force application. They will be assessed 48 miniscrew implants placed in patients in orthodontic treatment at the postgraduate clinical in Orthodontics, at School of Dentistry of Ribeirão Preto, University of São Paulo. They will be randomly divided into 4 groups: 1- LLLT and immediate force application; 2- LLLT and force application 4 weeks after implantation; 3- immediate force application without LLLT and 4- force application 4 weeks after implantation without LLLT. Orthodontic force of 150 gF will be applied for 3 months. A low power laser device Therapy XT with a wavelength of 660 nm and output of 100 mW immediately after implantation (energy density: 4J/cm2), and 808 nm with 100 mW (energy density: 8J/cm2), every 48 hours for two weeks in the following applications will be used. The stability will be assessed using Resonance Frequency Analysis (RFA) at three times: the implantation day (T1), one month (T2) and after 3 months of force application (T3). Stability measures will be evaluated in Implant Stability Quotient (ISQ). To assess the amount of miniscrew implant displacement, it will be used Cone Beam Computed Tomography (CBCT) at the beginning (CT1) and final of the application of orthodontic force (CT2). Three-dimensional models will be created in specific programs and superimpositions of CT1 and CT2 will be used to measure the distance in millimeters between inicial and final position. The evaluation will be carried out in three points: head of miniscrew implant (point C), thread (point R) and apex of miniscrew implant (point A). The results will be statistically analyzed according to nature of the data and the significance level to be adopted will be 5%.