Stereophotogrammetry-based Facial Depth Measurements: a Novel Method for Quantifying Facial Projection

Background: Orthognathic surgery leads to alteration of the spatial relationship of the mandible and maxilla resulting changes in the degree of facial projection. Traditional 2-dimensional cephalometry and photographic techniques do not provide data on facial depth. Though stereophotogrammetry can be used as a noninvasive method for evaluating facial depth, the unavailability of ethnicity-specific norms hinder its routine use in clinical practice. The objectives of this study were to (a) generate an analytic scheme suitable for evaluating facial depth using stereophotogrammetry and (b) create normative data for the facial depth measurements for young Hong Kong Chinese adults.

Methods: Stereophotographic images from 41 male and 45 female ethnic Chinese young adults without facial deformities were analyzed. Facial depth measurements were performed based on standard anthropometric landmarks, with the aid of 3dMDVultus software.

Results: All facial depth measurements were found in absolute terms to be significantly higher in males. In contrast, the upper face, maxillary, and sublabial depth indices were significantly higher in females, whereas no significant gender differences emerged for lower facial and maxillomandibular indices.

Conclusions: A novel method of using stereophotographic images for quantifying facial depth was evaluated. Normative facial depth measurements for young Hong Kong Chinese adults were established. This gender-specific database can be used as a reference in the diagnosis, treatment planning, or evaluation of outcomes after surgical correction of facial deformities.