Influence of early mineral deposits of silicate- and aluminate-based cements on push-out bond strength to root dentine

AimTo evaluate mineral trioxide aggregate (MTA), Biodentine and several formulations of calcium aluminate cements (CACb) in terms of their ability to release calcium ions (Ca2+) and form apatite-like precipitates after short-term immersion in phosphate-buffered saline (PBS) and its influence on the bond strength to the root-end cavity. MethodologyTen samples of MTA, Biodentine, CACb and calcium-enriched aluminate cement (CACb+) were placed in contact with PBS or deionized water for 14days. The cement surfaces were analysed using SEM, EDS-X and FTIR. Eighty standardized root-end cavities filled with the cements (ten samples of each cement) were immersed in PBS or deionized water for 14days, and the bond strengths were measured. Data from the push-out test were analysed using two-way ANOVA and Tukey's tests (=0.05). ResultsA gradual decrease was observed in Ca2+ concentrations and pH of all solutions. FTIR bands of different phases of hydroxyapatite were identified. Crystalline formation was observed on the surface of all cements after immersion in PBS. No significant difference was observed in the bond strength of the test materials (P>0.05); however, all cements without contact with the solution revealed significantly lower bond strength values than those in contact with the solution (P<0.05). ConclusionMTA, Biodentine, CACb e CACb+ were associated with precipitation of crystals after being in contact with PBS for 14days, indicated by different phases of hydroxyapatite crystalline formation, which also increased dislodgment resistance of the material from root-end cavities. The CACb+ had similar bond strengths and precipitation of crystals to existing materials.