Marginal discrepancy of monolithic and veneered all-ceramic crowns on titanium and zirconia implant abutments before and after adhesive cementation: a scanning electron microscopy analysis.

摘要

To evaluate the marginal discrepancy of monolithic and veneered all-ceramic crown systems cemented on titanium (Ti) and zirconia implant abutments.Sixty customized implant abutments for a maxillary right central incisor were fabricated of Ti and zirconia (n = 30 of each) for an internal-connection implant system. All-ceramic crowns were fabricated using the following systems (n = 10 per group): monolithic with computer-aided design/computer-assisted manufacture (CAD/CAM) lithium disilicate (MLD), pressed lithium disilicate (PLD), or CAD yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP). The frameworks of the PLD and Y-TZP systems were manually veneered with a fluorapatite-based ceramic. The crowns were cemented to their implant abutments, and the absolute marginal discrepancy of the gap was measured before and after cementation. Data were analyzed statistically.Marginal discrepancies were significantly influenced by the crown system and by cementation, but the material did not significantly affect the results. Interaction terms were not significant. Y-TZP crowns on both Ti and zirconia abutments presented the smallest mean marginal discrepancies before (52.1 ± 17 μm and 56.2 ± 11 μm, respectively) and after cementation (98.7 ± 17 μm and 101.8 ± 16 μm, respectively). Before cementation, MLD crowns showed significantly larger mean marginal openings than PLD crowns on both Ti and zirconia abutments (75.2 ± 12 and 77.5 ± 13 μm for MLD, 52.1 ± 17 μm and 69.7 ± 8 μm for PLD, respectively). After cementation, both Ti and zirconia abutments with MLD crowns (113.5 ± 12 μm and 118.3 ± 14 μm, respectively) showed significantly larger values than with PLD crowns (98.7 ± 17 μm and 109.4 ± 9 μm, respectively).Manually veneered Y-TZP crowns demonstrated more favorable marginal fit on both Ti and zirconia implant abutments before and after cementation compared to those of MLD and PLD.