Background. Comprehensive orthodontic treatment may last for 20-24 months. Reducing the treatment time has become a common demand from both patients and orthodontists. Minimally invasive piezocision is one of the suggested approaches to accelerate the orthodontic tooth movement. Objectives. The aim of this randomized controlled clinical trial was to assess the effectiveness of the flapless piezocision procedure in accelerating the retraction of upper incisors. Material and methods. A single-blinded, parallel-group randomized controlled clinical trial was conducted at the Department of Orthodontics at the University of Damascus Dental School, Syria. The study involved 42 patients (11 males, 31 females) at the age of 16-31 years (mean age: 19.15 years). The patients had class II division I malocclusion and were treated with fixed appliances using the two-step retraction technique. With an allocation ratio of 1:1, the participants were randomly assigned to either the experimental group (n = 21) or the control group (n = 21) using a computer-generated list of random numbers. Allocation was concealed due to the use of sequentially numbered, opaque, sealed envelopes. The primary outcomes were the rate of incisor retraction (RIR) and the time required for retraction. The outcome assessor was blinded. Results. The data analysis included 20 patients in each group. The rate of incisor retraction significantly increased in the experimental group by 53%, with a significant shortening of the retraction time in the experimental group by 27% (p < 0.001). The rate of anchorage loss was significantly lesser in the experimental group (p < 0.001). Regarding the cephalometric assessment, incisor tipping was significantly greater in the control group than in the experimental group. Skeletal measurements showed insignificant changes following retraction between the 2 groups. Conclusions. The piezocision procedure was found to be effective in accelerating the retraction of 4 upper incisors, reducing the retraction time, preserving anchorage and enhancing root torque control during retraction.

Within the limits of this study, the modified distractor caused a bodily movement of the canine with a minimal tipping. Further research is required on a long-term basis on a larger group of patients to gain more insight on the observed changes.