Dimensional Accuracy of Orbital Prostheses Manufactured Using the CAD/CAM System

Objective: To assess the dimensional accuracy of orbital prostheses based on reversed images generated by the CAD/CAM system from CT scans. Methods: Computed tomography of the faces of 15 adults, men and women older than 25 years of age, not bearing any congenital or acquired craniofacial defects, were processed using CAD (computer-aided design) software to produce 30 reversed 3D models of the orbital region. These models were processed using the CAM system (computer-aided manufacturing), by means of selective laser sintering, to generate surface prototypes of the volunteers orbital regions. Two moulage impressions of the faces of each volunteer were taken in order to manufacture 15 pairs of casts. Orbital defects were created on the right or left side of each cast. The surface prototypes were adapted to the casts and flasked to fabricate silicone prostheses. The establishment of anthropometric landmarks on the orbital region and facial midline allowed for the data collection of 31 linear measurements, used to assess the dimensional accuracy of the orbital prostheses and their location on the face. Results: The comparative statistical analysis, using the Mann-Whitney test (p ≤ 0.05), of the linear measurements taken from the orbital prostheses and the opposite sides that originated the surface prototypes demonstrated that the orbital prostheses presented similar vertical, transversal and oblique dimensions, as well as similar depth. There was no transverse or oblique displacement of the prostheses. Conclusions: From a clinical perspective, the small differences observed after analyzing all the 31 linear measurements did not indicate facial asymmetry. The dimensional accuracy of the orbital prostheses suggested that the CAD/CAM system assessed herein may be applicable to clinical purposes. Funding agency grant: Brazil, Fapesp 06/03765-4.