FACIAL PROFILE CHANGES DURING AND AFTER HERBST APPLIANCE TREATMENT

The short- and long-term effects of the Herbst appliance on the facial profile were determined in 69 Class II, division 1 malocclusions treated for 7 months and followed for 5-10 years post-treatment. Forty-nine subjects exhibited a stable long-term treatment result, while 20 cases relapsed. Lateral cephalometric radiographs from before treatment, after treatment, 6 months post-treatment, and 5-10 years post-treatment were analysed. As a rule Herbst treatment resulted in a reduction of the facial hard and soft tissue profile convexity. In relation to the E-line, the upper lip became retrusive, while the lower lip remained, on average, unchanged. During the post-treatment period of 5-10 years the hard tissue profile convexity was, on average, reduced in both the stable and relapse groups. When excluding the nose in the soft tissue profile evaluation, the facial profile convexity was, on average, reduced in the stable group while it remained unchanged in the relapse group. When including the nose in the evaluation, an average increase in the profile convexity occurred in both examination groups. Furthermore, the upper and lower lips became retrusive in both groups. For all the variables, however, large individual variations existed. In conclusion, it can be said that the Herbst appliance improves the facial hard and soft tissue profiles. Due to post-treatment growth changes the long-term effects of therapy are, however, variable and unpredictable.