Electronic Thesis and Dissertation Repository

Degree

Master of Clinical Science

Program

Orthodontics

Supervisor

Ali Tassi

Abstract

The purpose of this study was to evaluate the differences in dental and skeletal changes induced by the ForsusTM Class II dentoalveolar corrector in Class II patients with varying vertical skeletal growth patterns. The sample consisted of 26 (mean age 12.9 ± 1.3 years) Brachyfacial (BF) (SN-MP < 30o) consecutively treated Forsus subjects, 16 (mean age 13.1 ± 0.8 years) BF untreated Class II subjects (control subjects), 12 (mean age 12.3 ± 1.2 years) Nonbrachyfacial (NBF) (SN-MP ≥ 30o) consecutively treated Forsus subjects, and 8 (mean age 13.2 ± 0.9 years) NBF untreated Class II subjects (control). Lateral cephalograms were digitized and analyzed at the start (T1) and end (T2) of comprehensive orthodontic treatment or observation. The data was analyzed using Kruskal-Wallis non-parametric testing to determine statistical differences in the treatment changes (T2-T1) between treatment and control groups within the total sample, and within the vertical subgroups. In addition, the same statistical analysis was performed within the treatment sample comparing treatment changes between the BF and NBF subgroups.

The Forsus appliance demonstrated similar treatment changes when comparing BF and NBF treated subjects to the untreated controls. The treatment groups exhibited significant mesialization of the mandibular dentition with intrusion of the mandibular incisors. They also demonstrated significant distalization of the maxillary molar and restriction of the maxilla in the anteroposterior direction. The effects were not significantly different between the BF and NBF groups within treatment except for a greater restriction in maxillary length that was seen in the NBF group.

In conclusion, the Forsus appliance can be used to provide Class II correction in patients with different underlying vertical growth patterns with similar skeletal and dentoalveolar treatment effects.


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