Three-dimensional assessment of buccal alveolar bone after rapid and slow maxillary expansion: A clinical trial study
ABSTRACT The purposes of this study were to analyze and compare the immediate effects of rapid and slow maxillary expansion protocols, accomplished by Haas-type palatal expanders activated in different frequencies of activation on the positioning of the maxillary first permanent molars and on the buccal alveolar bones of these teeth with cone-beam computerized tomography.
The sample consisted of 33 children (18 girls, 15 boys; mean age, 9 years) randomly distributed into 2 groups: rapid maxillary expansion (n = 17) and slow maxillary expansion (n = 16). Patients in the rapid maxillary expansion group received 2 turns of activation (0.4 mm) per day, and those in the slow maxillary expansion group received 2 turns of activation (0.4 mm) per week until 8 mm of expansion was achieved in both groups. Cone-beam computerized tomography images were taken before treatment and after stabilization of the jackscrews. Data were gathered through a standardized analysis of cone-beam computerized tomography images. Intragroup statistical analysis was accomplished with the Wilcoxon matched-pairs test, and intergroup statistical analysis was accomplished with analysis of variance. Linear relationships, among all variables, were determined by Spearman correlation.
Both protocols caused buccal displacement of the maxillary first permanent molars, which had more bodily displacement in the slow maxillary expansion group, whereas more inclination was observed in the rapid maxillary expansion group. Vertical and horizontal bone losses were found in both groups; however, the slow maxillary expansion group had major bone loss. Periodontal modifications in both groups should be carefully considered because of the reduction of spatial resolution in the cone-beam computerized tomography examinations after stabilization of the jackscrews. Modifications in the frequency of activation of the palatal expander might influence the dental and periodontal effects of palatal expansion.
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ABSTRACT: Abstract This case report presents the successful use of palatal mini-implants for rapid maxillary expansion and mandibular distalization in a skeletal Class III malocclusion. The patient was a 13-year-old girl with the chief complaint of facial asymmetry and a protruded chin. Camouflage orthodontic treatment was chosen, acknowledging the possibility of need for orthognathic surgery after completion of her growth. A bone-borne rapid expander (BBRME) was used to correct the transverse discrepancy and was then used as indirect anchorage for distalization of the lower dentition with Class III elastics. As a result, a Class I occlusion with favorable inclination of the upper teeth was achieved without any adverse effects. The total treatment period was 25 months. Therefore, BBRME can be considered an alternative treatment in skeletal Class III malocclusion.The Angle Orthodontist 07/2014; 85(2). DOI:10.2319/031314-189.1 · 1.28 Impact Factor
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ABSTRACT: To assess the effectiveness of a Haas expander anchored to deciduous teeth in changing dental arch dimension and improving crowding and to evaluate stability of changes until permanent dentition. Study Design: closed cohort retrospective and case-control study. Eighteen patients undergoing early treatment for lateral crossbite (mean age 7.6 yrs; SD 1.0) at two practices located in La Spezia and Massa (Italy) were analysed. The treated group was compared with 72 control subjects divided into: 32 untreated adolescents with and without lateral crossbite and the same canine dental class as treated patients before expansion (Class II Division 2), 18 adults and 18 adolescents with dental Class I. All groups were matched for gender (ratio males:females, 8:10). The dental casts images of treated patients were digitally measured before and after treatment, and in permanent dentition. Patients at the last follow-up were compared with control subjects. In treated patients the increase in intermolar width and the improvement in anterior crowding were significant and stable until adolescence. Untreated adolescents with lateral crossbite showed the narrowest transversal widths and the highest irregularity. No difference was found among treated patients, adolescents without lateral crossbite, and adolescents and adults with a normal occlusion. The Haas expander anchored on deciduous teeth is effective in improving dental arch constriction and crowding in patients treated for lateral crossbite. The result is stable until permanent dentition. In absence of treatment, constriction of dental arch may persist, with a higher level of irregularity.European Journal of Paediatric Dentistry 06/2015; 16(2):115-122. · 0.48 Impact Factor
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ABSTRACT: Anchorage onto permanent dentition is a common procedure in rapid maxillary expansion. However, replacing first permanent molars with the second deciduous molars seems to be an option to reduce some negative side effects during orthodontic treatment. The purpose of this study was to evaluate the dental effect of rapid maxillary expansion with anchorage exclusively onto deciduous teeth performed in the first period of transition. Twenty patients with a lateral cross-bite treated exclusively by a Haas expander in early mixed dentition were retrospectively analyzed before treatment, at appliance removal, and at 21 months out of retention. The sagittal and transverse dimensions, together with the inter-canine arch and irregularity index, were digitally measured on scanned images of dental casts. The patients were compared with three balanced control groups (in total, 60 individuals) matched for gender. Two control groups had the same canine dental class as the treated group at T1, were in the inter-transitional period, and either had or lacked a lateral cross-bite. The last control group was comprised of adolescents in permanent dentition with a dental class I. The statistical analysis was performed by means of repeated-measures ANOVA for paired data and one-way ANOVA, the Kruskal-Wallis test, and the Mann-Whitney test for independent measures (α-level p < 0.05). At the end of follow-up (inter-transitional period of dentition), the dental arch dimensions of treated patients were similar to those of adolescents with a dental class I and significantly wider than those of patients with a lateral cross-bite. Also, the anterior irregularity index was lower among patients who had undergone expansion treatments than in all untreated study participants. The Haas expander anchored to the deciduous teeth is effective in increasing the dental arch width in patients with a lateral cross-bite. The dimensions of the dental arch were modified earlier toward the values of the permanent dentition.12/2015; 16(1):93. DOI:10.1186/s40510-015-0093-x