Horizontal Dental Changes during First Stage of Treatment Using the MBT Technique

Objective: The purpose of this study was to evaluate the dental movements of the labial segment and the canines during leveling and alignment using pre-adjusted appliances and light forces with the MBT technique. The effect of lacebacks on the horizontal movement of the first molars was also assessed. Materials and Methods: Fourteen patients with a mean age of 14.08 years were selected for this before-after clinical study. Dental casts were prepared for each subject at the onset of the study followed by banding and bonding using preadjusted brackets. A lateral cephalogram was taken with the appliances in place (T0). All patients underwent exraction of the four first premolars and treatment started using the MBT technique. A second set of casts and another cephalogram was obtained after 8 weeks (T1). Results: All contact point displacements decreased between T1 and T2 with the mean (SD) of -7.65 (4.16) mm in the upper arch; -7.07(3.28) mm in the lower arch. Retroclination was observed in the maxillary and mandibular incisors with the mean value of -0.021 (1.696) mm and -0.021 (1.515) mm during the study period respectively. The lower first molars showed 0.0207 (0.9657) mm displacement and the upper first molars showed 0.665 (1.296) mm mesial movement in the horizontal plane. The upper and lower canines moved distally and were uprighted, respectively. A significant increase was found in the mandibular intercanine width (P= 0.004). Conclusion: The results of this study are in favor of using preadjusted brackets for orthodontic treatment. In premolar-extraction, cases receiving preadjusted edgewise appliances; the lower labial segment does not procline during the leveling stage.