Cross-sectional human study of soft tissue chin (STC) thickness in adult patients in relation to sex, facial pattern and skeletal class.

PURPOSE: The aim of this study was to study the relations between the soft tissue chin (STC) and sex, skeletal class, and facial pattern; and to describe the shape and behavior of the STC.

METHODS

385 non-growing patients were selected, 206 women and 179 men, with a mean age of 28.8 years (SD 4.2). Patients were divided into groups by skeletal class (class I, II or III) and facial pattern (brachyfacial, mesofacial or dolichofacial). STC thicknesses were measured at pogonion (Pg), soft pogonion (Pg'), gnathion (Gn), soft gnathion (Gn'), menton (Me) and soft menton (Me') in the CBCTs.

RESULTS

Sexual dimorphism was observed at Pg-Pg' and Me-Me'. STC thickness was not related to skeletal class but related to facial pattern. Pg-Pg' and Me-Me' measurements showed significant differences to the combination of skeletal class/facial pattern. STC thickness was not homogenous in terms of shape and behavior.

CONCLUSIONS

The results provide evidence of a strong but complex relationship between sex, facial pattern, skeletal class and STC thickness; for this reason, each patient must be evaluated individually before undergoing orthodontics or orthognathic surgery involving the mandible and the mandibular symphysis.