Marginal and internal fit of three-unit fixed dental prostheses fabricated from translucent multicolored zirconia: Framework versus complete contour design

Statement of problem. Translucent multicolored zirconia materials enable more esthetic complete contour zirconia fixed dental prostheses (FDPs) than conventional zirconia, which exhibits low translucency and high opacity and is monochromatic. However, how the marginal and internal fit of translucent multicolored zirconia FDPs compare with those of traditional frameworks that require veneering is unclear. Purpose. The purpose of this in vitro study was to compare the marginal and internal fit of frameworks and complete contour 3-unit FDPs fabricated from translucent multicolored zirconia. Material and methods. Frameworks with a thickness of 0.5 mm and complete contour FDPs with a thickness of 0.8 to 1.5 mm were manufactured by using a workflow similar to one from a zirconia master model (mandibular left second premolar-mandibular left second molar). Two polyvinyl siloxane replicas were made for each specimen to measure the marginal and internal fit. Measurement locations were mesial, lingual, buccal, and distal for each abutment. In these locations, the marginal opening (MO), chamfer area (CA), axial wall (AW), and occlusal area (OC) were measured. The data were analyzed with 2-way ANOVA and the Bonferroni post hoc test (alpha=.05). Results. Frameworks showed significantly better mean +/- standard deviation fit values than complete contour 3-unit FDPs at measurement areas MO (frameworks: 112 +/- 22 mu m, complete contour FDPs: 144 +/- 37 mu m) (P=.013), CA (frameworks: 89 +/- 12 mu m, complete contour FDPs: 110 +/- 22 mu m) (P=.006), and OC (frameworks: 182 +/- 36 mu m, complete contour FDPs: 244 +/- 64 mu m) (P=.008). At the measurement area AW (frameworks: 47 +/- 7 mu m, complete contour FDPs: 50 +/- 9 mu m of each location, no significant difference was observed between frameworks and complete contour FDPs (P=.361). Conclusions. Design differences in 3-unit FDPs fabricated from translucent multicolored zirconia influenced the marginal and internal fit. Frameworks had smaller marginal fit than complete contour FDPs for translucent multicolored zirconia.