Objective: The current design methods for the surface texture of prostheses are unsatisfactory: the line-drawing method relies heavily on the subjective experience of technicians, and the powder-coating method requires high costs. A new innovative method is proposed: curvature-analysis with reverse engineering. The objective was to compare operation times and esthetic parameters in generating surface textures among the three methods.
Method and materials: Twenty-seven patients with maxillary central incisor fixed dental prostheses were randomly divided into three groups, and prostheses were built by three technicians using line-drawing, powder-coating, or curvature-analysis methods, respectively. Porcelain grinding times were recorded. The final prostheses were analyzed regarding the three-dimensional deviation from the control group that used the contralateral tooth. A senior technician and clinician made a single-blind evaluation of the prostheses' surface texture.
Results: In the curvature-analysis method, large, medium, and small curvatures effectively showed an intrinsic labial surface, the developmental groove, and other surface morphology structures, respectively. Operation times in the line-drawing, powder-coating, and curvature-analysis methods were 19.51 ± 0.95, 16.87 ± 1.30, and 12.41 ± 0.94 minutes, respectively, with statistically significant differences among the three methods; evaluation scores were statistically significantly different between the line-drawing and curvature-analysis methods. The three-dimensional deviation root mean square values were 0.451 ± 0.083, 0.396 ± 0.029, and 0.295 ± 0.080 mm, respectively, indicating curvature analysis had the smallest three-dimensional deviation.
Conclusions: Curvature analysis helps manufacture the surface texture accurately with enhanced efficiency, improving esthetics and reducing operation time and material waste.
Keywords: curvature; dental technology; fixed dental prosthesis; reverse engineering; surface texture; three-dimensional deviation.