Evaluation of the Marginal Fit of Computer-Aided Design and Computer-Aided Manufacturing versus Three-dimensional-printed Inlays

INTRODUCTION: Marginal adaptation is a significant factor influencing the longevity and clinical success of indirect restorations. Digital fabrication techniques, including computer-aided design and computer-aided manufacturing (CAD-CAM) milling and three-dimensional (3D) printing, have improved precision, but comparative data on their marginal fit remain limited, especially in the Indian context. The present study was done to assess the marginal fit of CAD-CAM-milled and 3D-printed inlays on standardized Class II premolar preparations. MATERIALS AND METHODS: An in vitro study was conducted on 200 extracted human premolars, randomly allocated into two groups: Group A, CAD-CAM inlays (n = 100) and Group B, 3D-printed inlays (n = 100). The marginal fit was assessed using the silicone replica technique under a stereomicroscope at × 40 magnification at occlusal, mesial, distal, and gingival margins. Statistical analysis included an independent t-test for intergroup comparison and one-way analysis of variance with Tukey's post hoc test for regional differences (P < 0.05). RESULTS: CAD-CAM inlays demonstrated significantly lower overall marginal gaps (68.42 ± 12.36 μm) compared to 3D-printed inlays (82.17 ± 15.04 μm, P < 0.001). Occlusal margins showed the least discrepancies, whereas gingival margins exhibited the highest gaps in both the groups. CONCLUSION: CAD-CAM inlays exhibit superior marginal adaptation compared to 3D-printed inlays, suggesting a preference in cases requiring a precise fit.