Shear Bond Strength of Different Cements on Prefabricated Composite Crowns

Objectives: Aim of the in vitro study was to evaluate the shear bond strength of four different dental cements Variolink II (Ivoclar Vivadent), Permacem 2.0 (DMG), Bifix SE (Voco GmbH) and Ketac cem (3M Espe) used in combination with prefabricated composite crowns (KidCadCrowns, vFM Dentallabor GmbH) on dentin of deciduous molars.
Methods: 48 freshly extracted deciduous molars were included in this study. In all teeth cervical dentinal cavities were prepared also allowing the simulation of dentin perfusion. The specimens were randomly assigned to four experimental groups of twelve each: V-Variolink II, P-Permacem 2.0, B-Bifix SE, K-Ketac cem. After application of the cements on the dentin specimens square samples of the prefabricated composite crowns with the size of 3x3 mm were fixed. The samples were stored for 24 hours at 36°C. Shear bond strength of the above mentioned material combinations was measured using an universal testing machine.
Results: Statistical analysis showed a significant influence of the used cements on shear bond strength (p< 0.001, ANOVA). For the four test series the following shear bond strengths were evaluated (mean values and standard deviations in MPa): V: 6.78 ± 2.89, P: 2.62 ± 1.05, B: 2.78±1.37 and K: 0.39 ± 0.20. Pairwise comparison showed significant higher shear bond strength in specimens treated with Variolink (V) compared to the other groups (p<0,05, ANOVA). Specimens treated with Ketac cem (K) showed significant lower values compared to the other groups (p<0,05, ANOVA). The comparison of Bifix SE (B) and Permacem 2.0 (P) showed no significantly different shear bond strengths (p>0,05, ANOVA).
Conclusions: Regarding the limitations of an in vitro study it can be concluded that the cementation of prefabricated composite crowns to deciduous teeth with Variolink II can be recommended in relation to shear bond strength.