Treatment effects of the mandibular anterior repositioning appliance on patients with Class II malocclusion.

The mandibular anterior repositioning appliance (MARA) is a tooth-borne functional appliance for use in patients with Class II malocclusions; it positions the mandible forward into a Class I occlusion. The aim of this study was to investigate the MARA's dental and skeletal effects on anterior, posterior, and vertical changes in 30 Class II patients. The treatment group consisted of 12 boys with an average age of 11.2 years and 18 girls with an average age of 11.3 years. A pretreatment cephalometric radiograph was taken 2 weeks before treatment, and a posttreatment cephalometric radiograph was taken 6 weeks after removal of the MARA, with an average treatment time of 10.7 months. The mean and standard deviation were calculated for each cephalometric variable, and Student t tests were performed to determine the statistical significance of the changes. The results of the study showed that the MARA produced measurable treatment effects on the skeletal and dental elements of the craniofacial complex. These effects included a considerable distalization of the maxillary molar, a measurable forward movement of the mandibular molar and incisor, a significant increase in mandibular length, and an increase in posterior face height. The effects of the MARA treatment were then compared with those of the Herbst and Fränkel appliances. The treatment results of the MARA were very similar to those produced by the Herbst appliance but with less headgear effect on the maxilla and less mandibular incisor proclination than observed in the Herbst treatment group.