ALTERNATE RAPID MAXILLARY EXPANSION AND CONSTRICTION (ALT-RAMEC) MAY BE MORE EFFECTIVE THAN RAPID MAXILLARY EXPANSION ALONE FOR PROTRACTION FACIAL MASK TREATMENT

Selection Criteria The authors searched 4 databases (MEDLINE, Cochrane Library, Scopus, and LILACS) and 2 trial registers (US National Institutes of Health Trials Register and WHO International Clinical Trials Registry Platform) up to February 2018. Manual searches were carried out by examining the reference lists of eligible articles. Randomized controlled trials (RCTs) evaluating the effectiveness of alternate rapid maxillary expansion and constriction combined with protraction facial mask (Alt-RAMEC/PFM) on class III malocclusion were selected. Growing patients exhibiting a class III skeletal pattern and maxillary retrusion, within the age range of 7 to 14 years, were considered for inclusion. Exclusion criteria were animal studies, case reports, case series, review articles, abstracts, and discussions. There were no restrictions regarding language, publication year, publication status, or publication type. A total of 1206 items were identified through the electronic and manual searches. Two authors screened these items independently and in duplicate. After the application of eligibility criteria, 5 studies were deemed eligible and included in the review. Key Study Factors Four of the 5 included studies were RCTs and the other 1 was a quasi-RCT. All of them compared Alt-RAMEC/PFM with rapid maxillary expansion combined with protraction facial mask (RME/PFM), using a banded hyrax as the rapid maxillary expansion (RME) appliance. A total of 147 participants were involved in these trials. Seventy-four patients (age 10.11-12.1 years) received Alt-RAMEC/PFM, and 73 patients (age 9.81-11.94 years) received RME/PFM. All 4 RCTs were conducted in China, and the quasi-RCT was carried out in Turkey. Two articles were published in English, whereas the remaining 3 articles were published in Chinese. The authors used the Cochrane Risk of Bias (RoB) Tool to assess the RoB of all included trials. Main Outcome Measures The primary outcomes of this review were the amount of overjet correction measured clinically or cephalometrically, and changes in the skeletal position of the maxilla and mandible as well as their interrelationship. Secondary outcomes included dental changes, soft tissue changes, vertical skeletal changes, duration of orthodontic treatment, number of orthodontic appointments, quality of treatment outcomes, patient-reported outcomes, and complications or adverse effects. Main Results Among the included studies, 1 had a low RoB, 3 had unclear RoB, while for the other study, the RoB was high. Changes in overjet, treatment duration, and adverse effects were only reported in 1 of the studies. Two trials reported upper incisor angulation and soft tissue changes, 3 of 4 trials assessed mandibular plane angle (MP-SN) and the lower incisor angulation, while 4 trials assessed the sella-nasion-subspinale angle, sella-nasion-supramental angle, and subspinale-nasion-supramental angle. None of the studies looked at differences in patient-reported outcomes or number of orthodontic appointments. Results of meta-analyses suggested that, based on 4 trials and moderate-certainty evidence, sella-nasion-subspinale angle, sella-nasion-supramental angle, and subspinale-nasion-supramental angle changes in the Alt-RAMEC/PFM group were 1.16 degrees (95% confidence interval [CI] = 0.65 to 1.66; P < .00001), 0.67 degrees (95% CI = 0.32 to 1.02; P = .0002), and 0.66 degrees (95% CI = 0.08 to 1.25; P = .03) greater than those of the REM/PFM group, respectively, indicating that Alt-RAMEC has a small but significantly greater skeletal effect. Based on 3 trials and low-certainty evidence, changes in the mandibular plane angle were not significantly different between Alt-RAMEC/PFM and RME/PFM (P = .78). According to 1 trial(1) with a high risk of bias, improvement in overjet was significantly greater in the Alt-RAMEC/PFM group (7.13 +/- 2.09 mm) than the RME/PFM group (4.97 +/- 2.07 mm; P < .001). However, based on low- to moderate-certainty evidence, changes in the lower (P = .51; 2 trials) and upper incisor angulation (P 5.98; 3 trials) were not significantly different between the 2 approaches. Two trials with low to unclear risk of bias assessed soft tissue changes and reported an improvement in total facial convexity favoring the Alt-RAMEC/PFM group. In addition, 1 trial with a low risk of bias found that time spent in the protraction phase was significantly shorter in the Alt-RAMEC group (MD = 1.78; P = .033), but the total treatment duration was not significantly different between the 2 approaches (MD = 0.24; P = .779). Conclusions The authors concluded that, compared to the RME/PFM approach, Alt-RAMEC/PFM may result in significantly more skeletal effects, as well as better improvement in overjet and profile. However, the overall body of evidence was only of low to moderate certainty.