Abstract
BackgroundTreatment effects of removable functional appliances in Class II malocclusion patients according to the pre-pubertal or pubertal growth phase has yet to be clarified.ObjectivesTo assess and compare skeletal and dentoalveolar effects of removable functional appliances in Class II malocclusion treatment between pre-pubertal and pubertal patients.Search methodsLiterature survey using the Medline, SCOPUS, LILACS and SciELO databases, the Cochrane Library from inception to May 31, 2015. A manual search was also performed.Selection criteriaRandomised (RCTs) or controlled clinical trials with a matched untreated control group. No restrictions were set regarding the type of removable appliance whenever used alone.Data collection and analysisFor the meta-analysis, cephalometric parameters on the supplementary mandibular growth were the main outcomes, with other cephalometric parameters considered as secondary outcomes. Risk of bias in individual and across studies were evaluated along with sensitivity analysis for low quality studies. Mean differences and 95% confidence intervals for annualised changes were computed according to a random model. Differences between pre-pubertal and pubertal patients were assessed by subgroup analyses. GRADE assessment was performed for the main outcomes.ResultsTwelve articles (but only 3 RCTs) were included accounting for 8 pre-pubertal and 7 pubertal groups. Overall supplementary total mandibular length and mandibular ramus height were 0.95 mm (0.38, 1.51) and 0.00 mm (-0.52, 0.53) for pre-pubertal patients and 2.91 mm (2.04, 3.79) and 2.18 mm (1.51, 2.86) for pubertal patients, respectively. The subgroup difference was significant for both parameters (p<0.001). No maxillary growth restrain or increase in facial divergence was seen in either subgroup. The GRADE assessment was low for the pre-pubertal patients, and generally moderate for the pubertal patients.ConclusionsTaking into account the limited quality and heterogeneity of the included studies, functional treatment by removable appliances may be effective in treating Class II malocclusion with clinically relevant skeletal effects if performed during the pubertal growth phase.
Highlights
The mandibular condyles, including their cartilage, have a primary role in the development and growth of the oro-facial complex
No maxillary growth restrain or increase in facial divergence was seen in either subgroup
The GRADE assessment was low for the pre-pubertal patients, and generally moderate for the pubertal patients
Summary
The mandibular condyles, including their cartilage, have a primary role in the development and growth of the oro-facial complex. Animal studies have shown that forward mandibular displacement enhances condylar growth resulting in significant changes in the morphology of the Mandible [1], [2] Such induced condylar growth has been shown to be characterized by a thickness of the condrogenic, proliferative, and hypertrophic layers of condylar cartilage on the posterior aspect of the condyle, yielding to an increase in total mandibular length [1], [2]. According to this biological evidence, an orthopaedic approach to treat skeletal Class II malocclusion in growing subjects is based on forward positioning of the mandible [3]. Treatment effects of removable functional appliances in Class II malocclusion patients according to the pre-pubertal or pubertal growth phase has yet to be clarified
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