The chin: skeletal and soft-tissue components.

The quantity of soft tissue overlying the symphysis menti affords an important attribute that can aid in determination of the correct surgical approach for optimal facial harmony. Xerograms of the facial profile of 100 patients with normal occlusion were analyzed by accepted radiographic cephalometric techniques. The relative contribution of skeletal structures and soft tissue of the chin was evaluated. All linear measurements were noted to be larger in males than in females, but in both groups, facial features were in proportion. In both males and females, the average thickness of the soft tissue overlying the symphysis menti progressively increased from the B point to midway between the B point and the pogonion. The soft tissue at the pogonion was thinner than at the B point. The soft tissue over the chin in males was significantly thicker than in females in all areas measured. When compared with patients over 60 years of age, the soft tissue at the B point was significantly thinner in patients 50 years of age and younger (p = 0.005), while the soft tissue at the pogonion was significantly thinner in patients 40 years of age and younger (p = 0.04). Pseudomacrogenia was noted in 6 percent of the patients, a diagnosis only possible with cephalometric analysis. An understanding of the relative contribution of the soft tissue to the chin can aid in the diagnosis and appropriate surgical management of chin incongruity. Furthermore, there is significant variation in skin thickness, which will influence the soft-tissue response to skeletal alteration. This has to be considered in planning a predictable surgical result.