This parallel two-arm randomized trial assessed skeletal changes following en masse and two-step anterior retraction using mini-implants. Of 110 patients screened, 14 were excluded due to ineligibility or refusal, leaving 96 participants randomized equally into two groups (48 each). All received the assigned intervention. During follow-up, 16 participants were lost because of bracket debonding, mini-implant failure, or discontinuation, resulting in 80 subjects (40 per group) included in the final analysis. All patients were treated with pre-adjusted edgewise appliances. After alignment and leveling, bilateral mini-implants were inserted between the maxillary second premolars and first molars, followed by extraction of the maxillary first premolars. Retraction was carried out according to group allocation either en masse or two-step. Lateral cephalograms taken before treatment and after incisor retraction were used to evaluate skeletal changes. Data were expressed as mean and standard deviation, with Wilcoxon signed-rank and Mann-Whitney U-tests applied for intra- and intergroup comparisons. Both methods produced significant sagittal and vertical changes. Although the two-step approach showed slightly greater maxillary retraction and ANB reduction, these differences likely related to baseline variation and biomechanics rather than true superiority. Vertical parameters increased in both groups, indicating posterior mandibular rotation, suggesting both techniques are equally effective.
Sattar et al. (Mon,) studied this question.