3-D laser scan reconstruction of the face and jaws: a new approach in cranio-maxillofacial surgery

The aim of this study was to finely adjust a method for the construction of a 3D-textured digital model of the face and dental arches of the maxilla and mandible from a laser scan of the face and plaster casts of the mouth and dental arches of patients with craniofacial malformations, and reconstruction after facial trauma or resection for neoplasm of facial skeleton. This is motivated by the need to obtain a virtual copy of the patient\u2019s face at no biological cost as an alternative to the method which involves using CT. The method based on CT provides a great deal of information, but the radiation absorbed by the patient is very high. Materials and methods The 3-D Laser scanner Konica Minolta VIVID 910 is used to scan the surface of the patient\u2019s face from different perspectives. These scanning perspectives are then recombined to reconstruct the three-dimensional facial features with minimal error in order to reconstruct the 3D-textured model of the face. A bite fork adapted to the purpose is used as the 3-D reference mark for repositioning the scan of the maxillar and mandibular arch plaster casts within the face model. The acquisition method was validated by verifying the consistency of several anthropometric measurements recorded in vivo with the corresponding measurements recorded on the virtual computer model. Results The patient\u2019s virtual face reconstructed by means of meshes can, be analysed as it is or can be later on converted into a NURBS (Nonuniform Rational B-Splines) surface. This virtual model is used not only to extrapolate isoparametric curves reproducing facial sections in the three spatial planes, but also to obtain further metric information regarding surface and volumes. This enables the patient\u2019s profile to be studied in the usual way, but also provides other useful anthropometric features, its volumetric characteristics and the changes induced by cranio-maxillofacial surgery. Conclusions The facial skin surface may serve as a sufficiently stable and invariable entity for registering patients for computer-assisted cranio-maxillofacial surgery. The proposed method proves an excellent way to study all the morphological facial features of patients with cranio-facial malformation or after facial trauma or resection for neoplasm of facial skeleton. The collection of an appropriate database of case studies, before and after surgical treatment, will enable us to implement a software for correlating dental arch displacements with changes in the corresponding facial surface