Marginal Adaptation and Surface Roughness of Indirect Composite Veneers: A Comparative Study of 3D Printing and Conventional Techniques

Background and Objectives: Indirect composite veneers in restorative dentistry depend on precise marginal fit and ideal surface roughness for long-term success. Marginal fit refers to how closely the edge of the veneer adapts to the tooth margin, where smaller gaps indicate better accuracy. Comparing 3D printing to conventional manufacturing techniques, the growing usage of digital technology may result in improvements in surface quality and accuracy. This study aimed to evaluate how traditional methods compare with 3D printing in terms of the fit and surface texture of indirect composite veneers. Materials and Method: Twenty extracted human teeth were used for the marginal fitness test and twenty composite discs for the surface roughness test in this in vitro study. Each set was divided into two groups (n=10 per group): One group for 3D printed composite veneers and the other for conventional indirect composite veneers. For marginal fit, the extracted teeth were prepared and ten veneers were fabricated for each group, and a stereomicroscope was used to measure the vertical marginal gaps at twelve reference points per each fabricated veneer. To measure surface roughness, disc-shaped specimens per group were fabricated. A contact profilometer was used to measure surface roughness both before and after polishing. Results: Both groups' marginal gaps fell into clinically acceptable limits. With a mean gap of 56.07 µm for the 3D-printed group and 59.61 µm for the conventional group, the difference in marginal gaps between the two groups was not statistically significant, indicating that both methods provided similar results (p = 0.457). Surface roughness was significantly reduced in both groups after polishing (p < 0.0001). The 3D-printed group demonstrated superior surface characteristics, showing significantly lower roughness values both before polishing (p = 0.039) and after polishing (p < 0.0001). Conclusion: Indirect techniques for fabrication of veneers from 3D printed composite can provide clinically acceptable marginal fit, and smoother surface than traditional composite. These results support the potential of using 3D printing to create indirect composite veneers. Keywords: Indirect composite veneers; 3D printing; Conventional fabrication; Marginal fit; Surface roughness