Development and Analysis of a Hydroxyapatite Supplemented Calcium Silicate Cement for Endodontic Treatment

Aim: To develop an endodontic cement using bovine bone-derived hydroxyapatite (BHA), Portland cement (PC), and a radiopacifier. Methods: BHA was manufactured from waste bovine bone and milled to form a powder. The cements were developed by the addition of BHA (10%/20%/30%/40% wt), 35% wt, zirconium oxide (radiopacifier) to Portland cement (PC). A 10% nanohydroxyapatite (NHA) cement containing PC and a radiopacifier, and a cement containing PC (PC65) and a radiopacifier were also manufactured as controls. The cements were characterised to evaluate their compressive strength, setting time, radiopacity, solubility, and pH. The biocompatibility was assessed using Saos-2 cells where ProRoot MTA acted as the control. Compressive strength, solubility and pH were evaluated over a 4-week curing period. Results: The compressive strength (CS) of all cements increased with the extended curing times, with a significant CS increase in all groups from day 1 to day 28. The BHA 10% exhibited significantly higher CS compared with the other cements at all time points investigated. The BHA 10% and 20% groups exhibited significantly longer setting times than BHA 30%, 40% and PC65. The addition of ZrO2 in concentrations above 20% wt and Ta2O5 at 30% wt resulted in a radiopacity equal to, or exceeding that of, ProRoot MTA. The experimental cements exhibited relatively low cytotoxicity, solubility and an alkaline pH. Conclusions: The addition of 10% and 20% BHA to an experimental PC-based cement containing 35% ZrO2 improved the material's mechanical strength while enabling similar radiopacity and biocompatibility to ProRoot MTA. Although BHA is a cost-effective, biomimetic additive that can improve the properties of calcium silicate endodontic cements, further studies are now warranted to determine its clinical potential.

Automated summary

The aim of this study was to develop an endodontic cement using bovine bone-derived hydroxyapatite (BHA), Portland cement (PC), and a radiopacifier. The results showed that the addition of 10% and 20% BHA improved the mechanical strength of the cement while maintaining similar radiopacity and biocompatibility to ProRoot MTA. This study is important for enhancing the properties of endodontic cements.