Post-pubertal effects of the Face Mask Protocol with and without Bite Block appliance in the orthopedic treatment of Class III malocclusion: a comparative evaluation.

OBJECTIVES

The purpose of this retrospective study was to compare the dento-skeletal changes observed in growing Class III patients treated with the Face Mask Protocol (FMP) with and without Bite Block (BB).

MATERIALS

Thirty subjects (12 f, 18 m) who underwent FM/BB therapy were compared to a matched group (FM) of 29 patients (15 f, 14 m) treated without BB. All patients were evaluated before treatment (T0), at the end of active treatment (T1), and at a post-pubertal follow-up observation (T2). A control group (CG) of 20 subjects (10 f, 10 m) with untreated Class III disharmony was used for the comparison of post-pubertal changes. Intergroup statistical comparisons were performed with the independent samples t-test (P < .05).

RESULTS

The comparison between treated samples showed a significant improvement of SN^GoGn (FM/BB vs FM, -2.1°), Overbite (FM/BB vs FM, +1.2 mm), and vertical position of lower molars FM/BB vs FM, -3 mm). When compared with the controls, both treated groups revealed a significant improvement of SNA (FM/BB, +1.8°; FM +2.1°), ANB (FM/BB +1.6°, FM +2.4°), gonial angle (FM/BB -4.9°; FM -4°), incisor inclination (Upper, FM/BB +1.7°, FM +2.3°; Lower, FM/BB -2.5°, FM -2.7°), and Overjet (FM/BB +3.2 mm; FM +4 mm). Improvement of SN^GoGn (-2.1°), Overbite (+1.8 mm), and vertical position of lower molars (-3.8 mm) were observed when FM/BB was compared with CG.

LIMITATIONS

Limitations are related to the difficulty to recruit a larger contemporary long-term control group due to ethical reasons.

CONCLUSION

Both FM protocols induced favorable changes in the treatment of Class III malocclusion with a good post-pubertal stability. The BB allows a more efficient control of the vertical skeletal relationship.