Apatite-Like Forming Ability, Porosity, And Bond Strength Of Calcium Aluminate Cement With Chitosan, Zirconium Oxide, And Hydroxyapatite Additives

This study evaluated the effect of chitosan, zirconium oxide, and hydroxyapatite on the apatite-like forming ability, porosity, and bond-strength of calcium-aluminate cements (C). Three hundred bovine root-slices were assigned to one of five groups, according to the material: MTA, C, C + chitosan (Cchi), C + zirconium oxide (Czio), and C + hydroxyapatite (Chap), and within each group, two subgroups, according to the immersion: deionized water or phosphate-buffered saline (PBS) up to 14 days. Assessments (n = 10) of apatite-like forming ability were performed using scanning-electron microscopy, energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, and x-ray diffraction. PBS was evaluated for pH and Ca2+ release (n = 10). Bond-strength was analyzed by push-out test (n = 10) and porosity by micro-CT (n = 10). Chemical and push-out data were analyzed by ANOVA and Tukey's tests (alpha = .05). Porosity data were analyzed by the Kruskal-Wallis and SNK tests (alpha = .05). Similar Ca/P ratios were observed between all groups (p > .05). The pH of MTA and Cchi were higher than that of other cements at d 3 and 6 (p < .05). Cchi had a higher release of Ca2+ up to 6 days (p < .05). All cements had lower porosity after PBS (p < .05). Cchi and Chap had similar porosity reduction (p > .05), and were higher than MTA, C, and Czio (p < .05). Cchi had higher bond-strength than the other groups (p < .05). PBS samples had higher bond-strength (p < .05). All cements had hydroxyapatite deposition and the chitosan blend had the lowest porosity and the highest bond-strength.