Three-dimensional acquisition technologies for facial soft tissues - Applications and prospects in orthognathic surgery.

The management of patients with dento-maxillofacial deformities is based on assessments of the dental occlusion - facial skeleton - soft tissues triad. As societal demands and surgical practices have evolved, facial soft tissues have moved to the forefront of considerations in orthognathic surgery. Techniques are therefore required to analyze facial soft tissues objectively and reproducibly, for diagnosis, preoperative planning, and follow-up. Several technologies are currently capable of providing three-dimensional (3D) models of the face, either by 3D reconstruction of traditional computed tomography or cone beam computed tomography data, or directly by stereophotogrammetry, laser scanning or structured light scanning. Multimodal image registration techniques allow bone base, dental occlusion and facial soft tissue information to be combined in a 3D virtual patient. Three-dimensional cephalometric analysis of the facial skeleton and skin is now perfectly integrated in virtual planning and is gradually gaining in automation and accuracy. Photorealistic 3D simulations allow optimal soft tissue planning and facilitate physician-patient communication. Finally, these facial modeling techniques facilitate post-operative studies of soft tissues, which generally involve comparisons of volumetric data. There are many research avenues to pursue and technical improvements are to be expected, particularly through the development of big data and artificial intelligence approaches.