EFFECT OF BUILDING ORIENTATION ON MARGINAL GAP AND INTERNAL FIT OF THE IMPLANT-SUPPORTED 3D-PRINTED PROVISIONAL CROWN

Abstract

With the increasing popularity of immediate implant placement and restoration, precise fabrication methods for provisional restorations have become crucial since it helps preserving the soft tissue around the implant. 3D-printed PMMA provides cost-effective alternatives despite concerns about polymerization shrinkage. Previous studies have shown that building orientation for 3D-printed methods can affect the marginal gap and internal fit of the restoration. This study aims to examine the effect of building orientation on the marginal gap and internal fit of implantsupported provisional prostheses. Materials and Methods: The implant-supported provisional restoration of the right maxillary central incisor was designed by complete digital workflow using 3shape software. The virtual implant crowns were fabricated with 3D-printer (DLP technology) in five different building orientations (0°,30°,45°,60° and 90°) with 10 samples per group. The samples underwent post-processing methods according to the manufacturer’s recommendation. Marginal gap and internal fit examination were conducted using a digital silicone replica technique and superimposition method. After digitizing the silicone replica into .stl file, the gap distances were measured at sixteen reference points for each sample using Artec Studio 18 software. The degree of discrepancy was reported in color mapping. The measurements were statistically analyzed using One-way ANOVA and multiple comparison with Tukey Post-hoc test.D Results: Statistical analysis revealed significant differences in marginal, cervical, axial, and occlusal gap across the five groups (p < 0.05). The 30° and 45° groups (19.08 µm and 19.10 µm, respectively) had a significantly smaller marginal gap than the other groups. Corresponding to the RMSE at the margin of the Ti-base abutment. The RMSE of overall internal fit showed 90° group had the largest cement gap at mean value of 83.57 ± 8.86 µm. Conclusion: Building orientation in 3D printing significantly affects the marginal gap and internal fit of implant-supported provisional restorations. The 30° and 45° orientation demonstrated the smallest marginal gap and superior internal fit, indicating it as the optimal angle for achieving high precision for 3D-printed implantsupported provisional crown.