Soft tissue profile changes after Functional Mandibular Advancer or Herbst appliance treatment in class II patients

The objective of the present study is to compare the effects on soft tissue profile in class II patients after treatment with either "Functional Mandibular Advancer" (FMA) or Herbst appliance.

The study included n = 42 patients treated with either FMA (n = 21) or Herbst appliance (n = 21) by the same experienced orthodontist. The treatment followed a single-step advancement protocol. Lateral cephalograms were analyzed through a set of customized measurements. The actual therapeutic effect was calculated using data from a growth survey. After testing for normal distribution and homogeneity of variance, data were analyzed by one-sample Student's t tests and independent Student's t tests. Statistical significance was set at p < 0.05.

For both FFAs, significant upper lip retrusion, increase in lower lip's thickness, and length of the lower face occurred. Additionally, significant lower lip retrusion and straightening of the profile were found in FMA and Herbst appliance patients. All remaining variables revealed no significant differences.

Treatment-related changes on the facial soft tissue profile could be regarded similar in class II patients treated with FMA or Herbst appliance. No treatment-related changes that were specific for FMA or Herbst appliance could be identified. Only moderate changes were noted comparing pre- and posttreatment soft tissue profiles.

Despite proven differences in skeletal and dental treatment effects, the facial profile has not to be taken into consideration when choosing between FMA and Herbst appliance for class II treatment.