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Changes in soft tissue profile following the treatment using a Herbst appliance--a photographic analysis.

BACKGROUND/AIM
Aesthetics is the reason for most of the class II malocclusion patients to opt for orthodontic treatment. In order to regulate retrognathic profile Herbst appliance for anterior movement of the mandible can be a treatment of choice. The aim of this study was to determine the soft tissue profile changes following Herbst appliance therapy on before and after treatment photos, using the computer program.


METHODS
This investigation was performed on profile photographs of 20 class II patients (12 females and 8 males) aged 18-23 years. Analysis of the changes in soft tissue facial structure relationships evident on the photographs before and after the Herbst appliance therapy was performed using Bentley Micro Station program. The first contour of the soft tissue profile was marked. The following reference lines were subsequently traced: Ricketts aesthetic E line and Juanita line. The area enclosed by these two lines included the nose, upper and lower lip, chin and free space in front of the lips. Using the computer program, the surfaces of the soft tissue structures and free space defined by the reference lines and profile contours were measured. Calculation of the relative proportion of surfaces was done for each photograph. The data obtained were then compared for each patient before and after the treatment. Skeletal and dentoalveolar treatment effects that support soft tissue changes were presented by the profile cephalometric parameters of sagital occlusion (SO) analysis.


RESULTS
A reduction in the relative surface of the upper lip in males (p < 0.01) and females (p < 0.05) was shown by the pictures. The space occupied by the chin was reduced after the treatment for females only (p < 0.05). The relative surface of the nasal soft tissues, that was included in the reference space was increased (p < 0.01) in both genders. The relationship between the soft tissue and empty surface was changed in favor of the empty surface (p < 0.05) in females. No statistically significant differences were found between the males and the females, before or after the Herbst appliance therapy. The soft tissue changes were the consequence of skeletal and dentoalveolar treatment effects: upper incisors retrusion, lower incisor protrusion and forward movement of the lower jaw.


CONCLUSIONS
The Herbst appliance therapy caused a significant improvement of the profile appearance. The extent of soft tissue changes that occur on its dentoalveolar and skeletal support is a complex issue.