Calcium release and mechanical strength of calcium fluoride doped carbonate apatite cement as a novel pulp capping agent

Carbonate apatite (CO₃Ap) is a bone substitute material, currently developed for pulp capping agent for its ability to stimulate mineralized tissue. Calcium fluoride (CaF₂) provides calcium and fluoride ions to form hydroxyapatite, fluorapatite, or fluorhydroxyapatite. Combining CO₃Ap and CaF₂ was expected to improve the performance of CO₃Ap as pulp capping material. This study aimed to assess the calcium release and mechanical strength of CaF₂ doped to CO3Ap in various concentration to evaluate the best ratio for this new combination. CaF₂ was added to CO3Ap cement in various concentration and released calcium ions were recorded by an atomic absorption spectrophotometer at day 1,7 and 14. Mechanical strength was evaluated by Diametral Tensile Strength (DTS) using a Universal Testing Machine. The study consisted of 6 groups (n = 4); G1 (60 % DCPA, 40% vaterite), G2 (60% DCPA, 30% vaterite, 10% CaF₂), G3 (60% DCPA, 20% vaterite, 20% CaF₂), G4 (60% DCPA, 10% vaterite, 30% CaF₂), G5 (60% DCPA, 40% CaF₂) all groups were mixed with 1mL Na₃PO₄, and G6 (calcium hydroxide mixed with water). Data were analyzed by one way ANOVA test and Post Hoc analysis. The calcium release rate of CaF₂ doped CO₃Ap were higher in day 7 and 14 of observation compared to CO₃Ap cement. The best ratio for calcium release of the new cement combination was in G3. The addition of 20% of CaF₂ had the highest DTS value. In conclusion, Group 3 was the best ratio for calcium ions release and mechanical strength, however, the addition of CaF₂ to CO₃Ap cement did not significantly improve the ability of CO₃Ap to release calcium ions nor its mechanical strength. This might be due to the particle size of CaF₂ material used. Further study was awaited using smaller particles of CaF₂ based on these initial findings.