Influence of ageing on the marginal quality of monolithic CAD CAM crowns on titanium base abutments
16339 ORAL COMMUNICATION BASIC RESEARCH
Background
The use of titanium bases (Ti-bases) as an implant abutment is a widely spread treatment option in a digital workflow in fixed prosthodontics. Despite all the benefits of this option, scarce information is available on the marginal quality and its stability over time and under function in the oral cavity. This factor may contribute for the long-term success of the implant-reconstruction complex.
Aim/Hypothesis
The aim of the study is to assess the influence of the cement material on the long-term marginal quality of monolithic CAD CAM crowns bonded on Ti-bases according to the ceramic material.
Material and Methods
108 Ti-bases were sandblasted (50-μm Al2O3, 2.5 bar) and 36 crowns of 3 different ceramic were milled (polymer-infiltrated ceramic network, lithium-disilicate, zirconia). For each ceramic the samples were divided in 3 groups (n = 12) according to the cement system used- Monobond Plus; Multilink Hybrid-Abutment (MH), Clearfil Ceramic Primer; Panavia V5 (PV), Scotchbond Universal; RelyX Ultimate (RU).Marginal fit between crown and Ti-base was measured (Keyence, 200x) before bonding to confirm equal fitting among the ceramics. The samples were aged (1200000 cycles). Before and after aging marginal quality was microscopically investigated and digital photographs of each margin were taken (Keyence, 200x) in buccal, proximal and oral aspects. The photographs were compared, and for each aspect, the margins were classified by receiving a value of 1-altered or 2-not altered. A mean value of all the 3 aspects was calculated for each sample.1-way ANOVA and Tukey HSD post hoc tests were used (α = 0.05).
Results
The marginal fit mean value before bonding was 13 ± 2.41 µm for polymer-infiltrated ceramic network, 15.25 ± 2.22 µm for lithium-disilicate and 11 ± 1.48 µm zirconia = 11 ± 1.48 µm. For polymer-infiltrated ceramic, the least alteration of the margin was found with PV cement (2.77% of alteration) (P < 0.05). With zirconia, RU revealed significant smaller margin alteration (27.7% of alteration) than the other cements (P < 0.05). For lithium-disilicate, RU (36.1% of alteration) and MH (38.9% of alteration) showed less margin alteration than PV (P < 0.05). Digital photographs revealed the presence of cracks in the cement line.
Conclusion and clinical implications
The marginal fit was equal within the groups. Marginal quality is affected by aging and cement system. Lithium-disilicate and zirconia performed best with RelyX Ultimate and polymer-infiltrated ceramic network reconstructions performed best with Panavia V5.
