Rapid Maxillary Expansion Group Research Articles

Evaluation of diagnostic criteria used for patients treated with activators

Sixty-one postorthodontic patients were examined to determine the effect of rapid and slow palatal expansion therapy on the periodontal supporting structures located at the buccal aspects on the maxillary first permanent molars. Twenty-eight patients were treated with a rapid maxillary expansion (RME) technique using a tissue-borne, fixed, split acrylic appliance (Fig. 1), while thirty-three underwent slow palatal expansion with a quad-helix appliance (Fig. 3). The two groups demonstrated mean increases in maxillary first molar width of 4.6 mm. and 4.3 mm., respectively. Twenty-eight patients treated with a similar light-wire edgewise technique but no palatal expansion were used as a control. Four periodontal parameters were examined, including level of marginal alveolar bone, attachment levels (from CEJ), probing depths, and width of keratinized gingiva. All measurements were made by the same examiner and recorded to the nearest 0.5 mm., using a specially machined and calibrated periodontal probe. The results demonstrated that both lateral expansion groups exhibited minimal differences in periodontal condition when compared to the control group. Periodontal status was good in all groups, with average attachment levels being 0.65 mm., 0.36 mm., and 0.51 mm. in the rapid expansion, slow expansion, and control groups, respectively. Although the mean differences were clinically small, individual variation was evident (Fig. 5). Among the few persons who exhibited the more marked periodontal breakdown at the central aspect of the first molars, most were found in the RME group. Except for the type of expansion therapy experienced, none of a number of other orthodontic variables examined demonstrated a statistically significant influence on the periodontal tissues.

Protection of enamel under orthodontic bands

The aim of this 2-arm parallel trial was to evaluate enamel demineralization after rapid maxillary expansion (RME) compared with an untreated control group using quantitative light-induced fluorescence.Thirty-six patients who needed RME as part of their orthodontic treatment were separated randomly into either the control group or the intervention group (RME). Eligibility criteria included crossbite, no previous orthodontic treatment, no systemic disease, and all permanent teeth erupted except second and third molars. The main outcome was quantitative evaluation of demineralization, and assessment of the vulnerability of each tooth to demineralization was the secondary outcome. Randomization was made at the start of the study with preprepared random number tables. Blinding was applicable for outcome assessment only. Patients in the RME group underwent expansion with a bonded acrylic expander; patients in the control group were untreated. Records were taken using quantitative light-induced fluorescence Digital Biluminator (Inspektor Research Systems, Amsterdam, The Netherlands) in pretreatment and posttreatment observation phases. The presence and extent of lesions on the buccal surfaces of all teeth, except the second and third molars, were assessed. The fluorescence loss, lesion area, and percentage of fluorescence loss were determined using the system's software. The numbers of teeth with more than a 5% change in fluorescence loss, were calculated. Data were analyzed with Wilcoxon signed rank, Mann-Whitney U, multivariate analysis of variance, and chi-square tests (P <0.05). Risk and odds ratios were calculated.A total of 36 patients were randomized to either the RME or the control group in a 1:1 ratio. This study was completed with 18 patients in the RME group (8 girls, 10 boys; mean age, 14.2 ± 1.0 years) and 18 patients in the control group (10 girls, 8 boys; mean age: 14.1 ± 0.8 years). All patients completed the study, and none were lost to follow-up. The area of demineralization decreased in the RME group (−17.50 mm2), which was a significantly greater decrease than in the control group (0.00) (effect size, −2.63; mean difference, −87.94; 95% confidence interval, −223.75-47.86; P = 0.008). No statistically significant difference was found for fluorescence loss. The numbers of teeth with demineralization and remineralization were higher in the treatment group. According to the risk ratio, the difference between groups regarding demineralization was not significant. No harm was found except gingivitis associated with the bonded appliance.RME therapy using a bonded expander does not increase enamel demineralization.This trial was not registered.The protocol was not published before trial commencement.