Relative effectiveness of facemask therapy with alternate maxillary expansion and constriction in the early treatment of Class III malocclusion

Abstract

This study aimed to investigate the relative efficacy of maxillary protraction combined with a modified alternate rapid maxillary expansion and constriction (Alt-RAMEC) protocol compared with conventional protocols in the early orthopedic treatment of skeletal Class III malocclusion. A sample of 39 patients was divided into 3 groups on the basis of different interventions. Conventional facemask (FM) with splint-type intraoral devices was performed in the FM group (7 males and 5 females; mean age, 9.53±1.37years). Maxillary expansion with an activation rate of 0.5mm/d (twice a day) followed by FM therapy was applied in the rapid maxillary expansion group (RME/FM) (6 males and 6 females; mean age, 9.31±1.60years). In the Alt-RAMEC/FM group (7 males and 8 females; mean age, 10.01±1.31years), Alt-RAMEC was started simultaneously and throughout the entire course of maxillary protraction, with repetitive alternations between activation and deactivation of expanders (0.5mm/d for 7days). The patients in all groups were instructed to wear FMs for a minimum of 12h/d. Pretreatment and posttreatment lateral cephalograms were all traced and measured. The Alt-RAMEC group showed statistically more significant maxillary advancement than other groups (A-VRP, 3.87mm vs 3.04mm [RME/FM], vs 2.04mm [FM]; P<0.05). Analysis of variance did not reveal significant intergroup differences in palatal plane angulation changes (P>0.05). No pronounced mandibular clockwise rotations were noted in the Alt-RAMEC/FM group with distinct intergroup differences (P<0.05). There were more skeletal effects (88.7%) during overjet correction in the Alt-RAMEC/FM protocol. A combination of the modified Alt-RAMEC protocol with FM revealed more favorable skeletal effects compared with FM and RME/FM protocols in treating prepubertal patients with maxillary deficiency.