New challenges for Reverse Engineering in facial treatments: how can the new 3-D non invasive surface measurements support diagnosis and treatment?

Reverse Engineering can provide new opportunities for facing the challenges of diagnosis and facial treatments, offering 3-D measurements that would have been impossible to obtain only a few years ago, in terms of the rich information detail, precision, accuracy and reliability. In this paper the main aspects and methods for skull and facial scanning and measurement are analyzed, taking into account volumetric methods (CT, MRI) and surface approaches (laser scanning, structured light and photogrammetry). These latter are particularly interesting because they avoid exposing the patient to ionizing radiation and any biological risk. The EU directives, in fact, require radiographic exposure to be minimized, and in the near future it will be considered justified only for true diseases, but not for aesthetic treatments and surgery, orthodontics, and malocclusions. Photogrammetry is very promising in view of the possibility of making a digital reconstruction of human faces; it seems to offer the best compromise in terms of achieving a realistic and accurate reproduction, as well as of the processing time, the simplicity and the cost of the equipment. New Software platforms have been developed to integrate the information acquired using different tools: photogrammetry, CT/CBCT, laser scans of dental cast study models. In this way a powerful multi-user database system can be created to track the patient’s imaging history throughout the treatment cycle and to predict the growth process and the outcome of treatments