Methods: An oily matrix was used as a CH vehicle and to form microspheres, as well as an alginate outer coating, aiding in the slow release of ions. The CHMS were compared to a commercially available CH medicament and to CH powder as controls. The release experiments were performed in extracted teeth(n=6) and in plastic centrifuge tubes(n=3) to determine the buffering effect occurring within teeth. The calcium release was measured with ultraviolet-visible spectroscopy and the pH was monitored with a pH meter.
Results: Results showed that the CHMS formulations showed the maximum sustained release in comparison to both controls. We were able to release Ca2+ for >4 months from the alginate-CHMSs in contrast to controls, which were depleted after one week under sink conditions. We also demonstrated control over the release profile of CH ions by varying the thickness of the alginate layer. The pH of samples from extracted teeth never rose above 9, whereas samples from centrifuge tubes had consistently high pH(12-14) indicating the buffering effect of teeth.
Conclusions: CHMSs present a viable alternative for currently available products for apexification. The slow release of Ca2+ and OH- should eliminate the need for periodic removal and refreshing of traditional intra-canal medicaments.
Support: NIH P30DE20742 & KL2RR024983
Keywords: Bioengineering, Delivery systems, Endodontics, Root canal fillings and Sealants
See more of: Pulp Biology & Regeneration Research