UCSF

Skeletal and dental effects of a novel application of the MARA appliance in adolescent patients with Class II malocclusions.

Garrett Rand Criswell, DDS, MBA

Purpose: The objectives of this study were to test the hypotheses that there is no significant increase in mandibular growth, no significant inhibition of maxillary growth, no significant relationship between mandibular inclination and mandibular growth, and no significant molar changes in patients treated with the MARA appliance compared to subjects who had no treatment intervention.

Methods: This is a retrospective longitudinal study of early adolescents with Class II malocclusions treated concurrently with the Mandibular Anterior Repositioning Appliance (MARA) and fixed Edgewise appliances over an extended duration (mean 3.5 years). The study was based on successive lateral cephalometric headfilms of 17 individuals (10 females and 7 males) from a private orthodontic office and on 9 control subjects matched for age, malocclusion, skeletal makeup and adequate records.

Results: The findings in this study show that concurrent MARA and fixed Edgewise appliance treatment did not result in any statistically significant difference in mandibular length (Ar-Pg), mandibular prognathism (SN-Pog), or maxillary position (SNA) when compared to the control group either for T1-T2 (mean 13 months) or during the overall period from T1-T3. During the course of treatment, the mandibular inclination and lower anterior facial height increased significantly. Pretreatment mandibular inclination did not have any measurable influence on the change in mandibular length or mandibular prognathism. Compared to controls, the maxillary molars experienced more distal tip and restricted forward movement, while the mandibular molars moved forward and extruded more, though none were statistically significant.

Conclusions: Treatment of Class II malocclusions with the concurrent use of the MARA and Edgewise appliances for an extended duration of time did not result in any statistically significant skeletal effects on the maxilla or mandible except for increasing the mandibular inclination and lower anterior facial height. The Class II malocclusion was effectively treated to a Class I occlusion in all subjects with the use of the MARA and Edgewise appliances largely through dental changes and some skeletal changes that were individually not statistically significant. There was significant individual variation in response to treatment.