Asymmetric dental arch treatment with Forsus fatigue appliances: Long-term results.

OBJECTIVES:: To investigate the treatment efficacy and follow-up stability of the asymmetric Forsus appliance by evaluating longitudinal changes in dental arch asymmetry on digital dental models from 21 patients.

MATERIALS AND METHODS:: Maxillary and mandibular reference lines were used for measurements of intra-arch asymmetry at pretreatment (T1), posttreatment (T2), and 4.2 years after treatment (T3). Maxillary and mandibular measurements were performed relative to the dental midline and anterior reference line on digital dental models. To determine the amount of asymmetry between the Class I and Class II sides of a given arch, all maxillary and mandibular parameters were measured on each side of the model separately. Repeated-measures analysis of variance/paired sample t-tests were performed to evaluate dental arch asymmetries at the P < .05 level.

RESULTS:: The alveolar transverse dimensions of the posterior segment of both arches were increased during treatment ( P < .05) and remained stable during the retention period. Class II subdivision malocclusion was caused by distal positioning of the mandibular canine, premolars, and first molar on the Class II side ( P < .05). Asymmetry was resolved by treatment with asymmetric Forsus appliances. The resolved asymmetry remained stable over the long term. There were no significant differences between T2 and T3 ( P > .05).

CONCLUSIONS:: The asymmetric Forsus appliance can be used to treat dental arch asymmetry in patients with Class II subdivision malocclusions.