Background: In this study, the physical properties of a calcium hydroxide/hydroxyapatite (CH/HA) cement were investigated as a novel bioactive material for the repair of bone and dental defects.
Methods: The powder phase, consisting of varying proportions of CH and HA, was mixed with glycol disalicylate as the liquid phase. The setting reaction produced an amorphous matrix containing dispersed HA particles adjacent to unreacted CH particles, as confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Elemental phosphorus mapping from X-ray analysis of SEM images further confirmed the presence and distribution of HA particles within the cement matrix.
Results: The cements exhibited setting times ranging from 2.9±0.5 to 7.8±0.8 min, depending on composition. Injectability increased from 68±3% to 86±6% as HA content increased, with no evidence of filter pressing or phase separation. After 24 h of setting, compressive strengths ranged from 55±2.6 to 62.3±2.8 MPa, which are higher than those typically reported for conventional calcium phosphate cements (CPCs). After 3 days of immersion in distilled water, the compressive strength decreased to 43.0–49.2 MPa due to partial matrix dissolution. The cements exhibited controlled calcium ion release over 28 days, with higher release observed in formulations containing greater amounts of CH. Furthermore, the pH of cement suspensions increased rapidly during the first 30 min and then stabilized in the alkaline range. Water solubility decreased from 6.85±0.12% to 2.95±0.12% with increasing hydroxyapatite content.
Conclusion: The developed CH/HA cement has promising mechanical and handling properties for potential biomedical applications in bone and dental tissue repair.