UBC Theses and Dissertations
Marginal fit and internal adaptation of monolithic zirconia 3-unit fixed dental prostheses : in-vitro study Alkaff, Nuha Abubaker A.
Objectives: To compare marginal fit and internal adaptation of monolithic zirconia (MZ) 3-unit fixed dental prostheses (FDPs) fabricated using two workflows: a full-chairside computer aided design/computer aided manufacturing (CAD/CAM) one (FCH) and a lab CAD/CAM one (LAB). Methods: Teeth #14 and #16 were prepared for MZ 3-unit FDP on an ivorine typodont. A total of 30 MZ 3-unit FDPs was fabricated using two processes: FCH and LAB. A CEREC Primescan intraoral scanner was used in both workflows to digitize the typodont model. FCH FDPs (n=15) were designed using CEREC SW 4.5.1 and milled using CEREC MC X. LAB FDPs (n=15) were designed using Exocad and milled using Zirkonzhan 600/V3 milling chamber. A fast-sintering protocol was used in both groups. A dual-scan technique was utilized to assess the cement space. The fit was evaluated at systematically selected areas: occlusal surface (OC), axial wall (AX) and margin (MA). Statistical analysis of the results was performed using univariate analysis of variance (ANOVA) with Scheffè post hoc test (P=0.05). Results: The measurements in FCH and LAB groups are within the clinically acceptable marginal and internal fit. The MA, AX and OC fit at retainer 14 of the FCH FDPs is 87.60 ±30. µm, 104.80 ±25.84 μm and 158.53 ±25.08 μm respectively, and of the LAB FDPs is 105 ±23.19 μm, 117.60 ±20.48 μm and 146.53 ±19.27 μm respectively. The MA, AX and OC fit at retainer 16 of the FCH FDPs is 67.40 ±26.50 μm, 94.53 ±15.51 μm and 141.53 ±34.34 μm respectively, and of the LAB FDPs is 95.53 ±30.51 μm, 115.47 ±15.66 μm and 138.07 ±20.36 μm respectively. The difference between the two groups is not statistically significant. Conclusion: The MZ 3-unit FDPs fabricated using FCH have clinically acceptable marginal and internal fit. This verifies the efficiency of FCH workflow in fabricating MZ multi-unit FDPs in a single visit, especially useful for people who cannot attend multiple visits to receive the restoration.
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Attribution-NonCommercial-NoDerivatives 4.0 International