Tricalcium silicate cements with resins and alternative radiopacifiers

Current dental and biomedical cements require radiopacity for clinical visibility. Radiopacifiers like zirconium oxide or barium zirconate are added, but their effects on cement hydration and bioactivity remain unclear. Prior research has shown that tricalcium silicate cements interact with liquid vehicles during setting. However, no prior work had resolved how different radiopacifiers or resins influence hydration byproducts like calcium hydroxide. This gap motivated an investigation into the setting mechanisms and radiopacifier effects on cement properties. The study aimed to clarify how these additives alter hydration, leaching, and bioactivity. It was already known that calcium hydroxide forms during cement hydration, but the role of radiopacifier choice and vehicle type had not been fully explored. This paper's contribution lies in examining how vehicle and radiopacifier combinations affect calcium leaching and surface mineralization. The study gap centered on the interplay between vehicle composition and radiopacifier in controlling cement behavior.

The study aimed to evaluate how different radiopacifiers and liquid vehicles influence the setting behavior and bioactivity of tricalcium silicate cements. The specific problem addressed was the lack of understanding about how radiopacifier type and resin vehicle affect hydration byproducts and leaching. The motivation stemmed from the need to improve cement formulations for clinical use. The researchers focused on two radiopacifiers: zirconium oxide and barium zirconate. They also tested three liquid vehicles: water, epoxy resin, and Bis-GMA-based resin. The study sought to determine how these combinations affect calcium hydroxide formation and surface mineralization. The goal was to assess the impact of vehicle and radiopacifier on leaching and bioactivity. The study also aimed to clarify the role of resins in hydration and calcium release. This work was driven by the need to optimize cement formulations for dental and biomedical applications.

The study used tricalcium silicate cement with 20% substitution of either zirconium oxide or barium zirconate as radiopacifiers. The cements were mixed with three liquid vehicles: water, epoxy resin, and Bis-GMA-based resin. Set materials were immersed in Hank's balanced salt solution for 28 days. Scanning electron microscopy and x-ray diffraction were used to analyze the setting mechanisms and surface microstructure. Bioactivity was assessed by examining surface changes and leaching in solution. Inductively coupled plasma emission spectroscopy measured ion release from the materials. The study compared calcium hydroxide formation across different vehicle and radiopacifier combinations. The effect of each vehicle on hydration and mineral deposition was evaluated. The researchers also tracked leaching of calcium, barium, and zirconium ions. The experimental design allowed for a detailed comparison of how vehicle and radiopacifier choices influence cement behavior.

Barium zirconate radiopacifier enhanced calcium hydroxide formation as shown by scanning electron microscopy and x-ray diffraction. Resin vehicles reduced calcium hydroxide formation, with Bis-GMA-based resin being most affected. Calcium hydroxide deposition occurred on all material surfaces regardless of vehicle type. Beta calcium phosphate formed on barium zirconate-containing materials immersed in HBSS. Inductively coupled plasma emission spectroscopy showed high calcium leaching from water and Bis-GMA-based resin mixtures. Barium leaching was highest in water-based cements. Zirconium leaching was negligible in zirconium oxide-based materials but measurable in barium zirconate mixtures. Resin type and radiopacifier composition affected calcium release and bioactivity. Light-cured Bis-GMA resins did not allow cement hydration but promoted calcium ion leaching. These findings highlight the impact of vehicle and radiopacifier on cement properties.

The study found that radiopacifier and vehicle choices significantly affect tricalcium silicate cement behavior. Barium zirconate increased calcium hydroxide formation compared to zirconium oxide. Resin vehicles reduced calcium hydroxide formation, with Bis-GMA-based resin being most affected. Calcium hydroxide deposition occurred on all surfaces regardless of vehicle. Beta calcium phosphate formed on barium zirconate-containing materials in HBSS. High calcium leaching was observed in water and Bis-GMA-based resin mixtures. Barium leaching was highest in water-based cements. Zirconium leaching was minimal in zirconium oxide mixtures but detectable in barium zirconate variants. Resin type and radiopacifier composition influenced calcium release and bioactivity. The authors concluded that vehicle and radiopacifier choices are critical for controlling cement hydration and leaching.