The aim of the present study was to determine the effects of early headgear treatment on mandibular growth and growth direction, when the headgear treatment is done in the early mixed dentition. The total study group comprised 68 children of both sexes (40 boys and 28 girls), aged 7.6 years (SD 0.3 years). The children had Class II occlusion or tendency to Class II. They were randomly divided into two groups of equal size, matched according to gender. In the headgear group treatment was initiated immediately. The mean treatment time was 16 months. In the second group, which was the control group, only interceptive procedures were performed during the follow-up period. The records, which included lateral cephalograms, were taken after follow-up periods of two and eight years. There was more favorable mandibular growth in the headgear group than in the controls, as the number of those with four degrees or more increase in the angle SNB was 33%, while the corresponding proportion in the controls was 8% (p < 0.05) (Fig. 1). Inside the headgear group there was a large individual variation in the change of the SNB value. It was found that those with favorable mandibular growth in the headgear group had significantly (p = 0.01) more labially inclined upper incisors than those with less favorable growth. Furthermore, those with favorable mandibular growth in the headgear group had significantly (p = 0.04) larger facial axis-angle (92.4, SD 4.16) already at seven years of age, compared those with less growth (89.0, SD 2.75). At eight-year follow-up in the headgear group, the change in SNB angle correlated with the change in facial axis (p < 0.001) and with NL/ML angle (p < 0.01). In conclusion, a significant mandibular anterior growth increase was found in a part of the patients after early use of headgear. The positive growth effect is dependent on mandibular growth direction, which can already be detected cephlometrically at seven years of age. Facial axis angle appears to be a good predictor of mandibular growth, when using headgear.
(Rev Esp Ortod. 2015;45(4):206-210)