Abstract:

Objective To design and fabricate canine rib prosthesis with full geometric shape based on computed tomography (CT) scan and stereo lithography apparatus (SLA) rapid prototyping, and evaluate the precision. Methods DICOM format files of the canine right seventh rib were subject to three-dimensional reconstruction and were transformed to STL format files by OsiriX software, which were then modified by UG software for establishment of computer-aided design (CAD) model. Files with IGS format were formed and subject to rapid prototyping, and canine rib prosthesis was manufactured with photosensitive materials. The rib prosthesis and authentic rib were scanned by three-dimensional laser scanning system, and were analyzed by Geomagic Qualify software. With authentic rib as the template, the deviation of ±0.5 mm was set, and the precision was evaluated. Results The canine rib prosthesis with full geometric shape was obtained with CT scan and SLA technique. About 30 000 point cloud data were acquired after three-dimensional laser scan of rib prosthesis. The maximum positive deviation, maximum negative deviation, average deviation and standard deviation were 1.764 mm, －2.126 mm, 0.183/－0.253 mm and 0.346 mm respectively between the prosthesis and authentic rib. About 88.17% of point cloud data ranged from －0.5 mm to 0.5 mm. Conclusion It is feasible to design and fabricate rib prosthesis with full geometric shape based on CT scan combined with CAD and SLA technique, which is rapid, direct and accurate. Improvement can be made based on the deviation suggested by the scanning.

Key words: digital scan, stereo lithograph, rapid prototyping, photosensitive resin, geometric shape, OsiriX software, Geomagic Qualify software, rib, canine