Effect of Luting Cement Opaqueness on the Final Colour of Titanium - Base Supported Lithium Disilicate Abutments

Objectives: Current approach in individualized abutments is to use titanium bases (Ti-bases) for supporting lithium disilicate ceramic abutments to achieve both esthetics and mechanical resistance against intraoral forces. Ti-bases might lead to greyish reflections from the highly translucent glass-ceramic abutments. To avoid this, an opaque luting resin cement use for adhering the individualized glass-ceramic abutment to the titanium base might be a solution for this clinically overlooked situation. The aim of this study was to compare two resin luting cements with different opaqueness on the final colour of lithium disilicate abutments supported by titanium bases. Materials and Methods: Twenty titanium bases (Conelog Ti-base, Camlog) were divided into two lutin gresin cement groups (n=10/group) (Panavia F 2.0 (P), Kuraray; Multilink Hybrid Abutment Cement (M), Ivoclar Vivadent). Twenty identical monolithic abutment crowns with a standard ceramic thickness of 2 mm in the gingival portion were milled out (Cerec MCXL, Sirona) from lithium disilicate blocks (e.max CAD abutment solutions MO, Ivoclar Vivadent). Ten abutment crowns for each cement group were luted to the titanium bases according to the manufacturers' instructions. A dental contact type spectrophotometer (Vita Easyshade, Vita Zahnfabrik, Germany) was used to measure the mean colour differences of both cement groups before locating the abutment crowns on titanium bases and after luting on these bases by CIE Lab formula. The interaction of ∆E values were analyzed by a one-way analysis of variance at 5 % level. Results: The final color of the abutment crowns were significantly affected by the M cement (P0.05). Cement M resulted in less color difference than P (P0.05). Conclusion: The final color of lithium disilicate abutment crowns was influenced from the opaquness of the luting cement. Keywords: lithium disilicate, cement opaqueness, customized ceramic abutment, translucency