Three - dimensional face morphometry

Facial anthropometry plays a key role in clinical assessments, providing an accurate diagnosis for different syndromes. Clinicians working with the head and face (maxillo-facial, plastic and aesthetic surgeons; orthodontists and prosthodontists) are the mostly interested in this three-dimensional information, being able to estimate the normal and abnormal growth, planning and evaluating surgical or orthodontic treatment, plastic surgeries and anthropometric studies.1,6 Currently, classic direct anthropometry is being replaced with various three-dimensional image (3D) analyzers, and the knowledge and application of this technology is essential for clinicians to analyze the information for planning and evaluating medical procedures and treatments. Facial landmarks (previously marked on the face of the subject) represent the link between conventional and digital anthropometry7: conventional anthropometry identifies soft-tissue landmarks, and places some instrument (calipers, protractors) over them. Fundamentally, digital anthropometry collects a set of digital landmarks from the soft-tissue surface, and uses their spatial x, y, z coordinates as end-points for calculations based on Euclidean geometry: linear distances and angles. Together with these classic measurements, mathematics and geometrics allow the assessment of more complex characteristics from the same set of landmarks used by conventional anthropometry: estimations of volumes and surfaces, analyses of symmetry, and detailed assessments of shape.2-5,8 Three-dimensional morphomeTry meThods Two main groups of instruments can be used for soft-tissue three-dimensional facial anthropometry: contact instruments (electromagnetic and electromechanical digitizers, ultrasound probes) and optical/non contact instruments (laser scanners, optoelectronic instruments, stereophotogrammetry, Moiré topography). All these instruments are not invasive and do not provoke pain or discomfort to the subjects. But both W h a t ’ s n e W i n D e n t i s t r y