Pulpal Response to Nano Hydroxyapatite, Mineral Trioxide Aggregate and Calcium Hydroxide when Used as a Direct Pulp Capping Agent: An in Vivo study

Nano hydroxyapatite (Nano-HA) and Mineral Trioxide Aggregate (MTA) because of its better qualities can be used as an alternative to calcium hydroxide in direct pulp capping procedures. The aim of the study was to compare the response of exposed human pulp to Nano-HA, Mineral Trioxide Aggregate and calcium hydroxide. Study design: The study was done on 30 premolars, ranging from patients between 11-15 years. Intentional pulp capping was done using one of the experimental materials. The extracted teeth were then subjected to staining procedure and evaluated for dentin bridge and pulpal response after 15 and 30 days. Intragroup comparisons of the observed values were analyzed using Chi-square test. Results: Nano-HA and MTA produced continuous dentin bridges. Dentin bridge that was formed in MTA group had regular pattern of dentinal tubules but no tubules were seen in the nano-HA group. Dentin bridge was not observed in Dycal group for the 15 days period in majority of the sample and by 30 days dentin bridge was observed that were both continuous and interrupted in equal number of samples. The initial inflammatory response and necrosis was more with Nano-HA and calcium hydroxide which reduced with time. Conclusion: MTA showed no inflammatory changes in majority of the samples in both the study periods. Necrosis was least observed in MTA group followed by Nano-HA. Vascularity increased in Nano-HA group in the initial periods which reduced with increasing time. Based on the ability of nano-HA to produce complete dentinal bridges, favorable cellular and vascular response, the material could be considered as an substitute and could be tried used as a direct pulp capping agent.

Nano Hydroxyapatite, MTA, Calcium Hydroxide, Direct pulp capping agents

1. Carrotte P.Endodontics: part 7. Preparing the root canal. Br Dent J. 197(10):603-613,2004.

2. Rowe AHR. Reaction of the rat molar pulp to various materials. Br Dent J. 122:291-300,1967.

3. Horsted P, El Attar K, Langeland K. Capping of monkey pulps with Dycal and a Caeugenol cement. Oral Surg Oral Med Oral Pathol.52(5):531-553, 1981.

4. Fang Y, Agrawal DK, Roy DM. Thermal stability of synthetic hydroxyapatite. In: Brown PW, Constantz B, editors. Hydroxyapatite and Related Materials. London: CRC Press, 269-282,1994.

5. Boone ME, Kafrawy AH. Pulp reaction to a tricalcium phosphate ceramic capping agent. Oral Surg Oral Med Oral Pathol. 47(4):369-371, 1979.

6. Chacko V,Kurikose S. Human pulpal response to mineral trioxide aggregate (MTA): a histologic study. J Clin Pediatr Dent. 30(3):203-209, 2006.

7. Jabbarifar E, Razavi SM, Ahmadi N. Histopathologic responses of dog’s dental pulp to mineral trioxide aggregate, bio active glass, formocresol, hydroxyapatite. Dent Res J.4(2):83-87, 2007.

8. Cvek M. A clinical report on partial pulpotomy and capping with calcium hydroxide in permanent incisors with complicated crown fractures. J Endod. 4(8):232-237, 1978.

9. Somerman MJ, Nathanson MA, Sauk JJ, Manson B. Human dentin matrix induces cartilage formation in vitro by mesenchymal cells derived from embryonic muscle. J Dent Res. 66(10):1551-1558, 1987.

10. Denissen HW, de Groot K. Immediate dental root implants from synthetic dense calcium hydroxyapatite. J Prosthet Dent. 1979 Nov; 42(5):551-6.

11. John A, Nair MB, Varma HK, Bernhardt A, Gelinsky M. Biodegradation and cytocompatibility studies of a triphasic ceramic-coated porous hydroxyapatite for bone substitute applications. Int J App Cer Tech. 2008 Jan;5(1):11-9.

12. Tsukamoto Y, Fukutani S, Mori M. Hydroxyapatite-induced alkaline phosphatase activity of human pulp fibroblasts, J Mater Sci Mater 3(3):180-183, 1992.

13. Mjor IA. Dentin predentin complex and its permeability: pathology and treatment overview. J Dent Res. 64 (Spec):621-627,1985.

14. Schroeder U. Effects of calcium hydroxide-containing pulp capping agents on pulp cell migration, proliferation and differentiation. J Dent Res. 64(Spec):541-548,1985.

15. Hayashi Y, Imai M, Yanagiguchi K, Viloria IL, IkedaT. Hydroxyapatite applied as direct pulp capping medicine substitutes for osteodentin. J Endod. 1999Apr;25(4):225-9.

16. Tagger M, Tagger E. Pulp capping in monkeys with Reolit and Life, two calcium hydroxide bases with different pH. J Endod. 11(9):394-400, 1985.

17. Pitt Ford TR, Roberts GJ. Immediate and delayed direct pulp capping with the use of a new visible light-cured calcium hydroxide preparation. Oral Surg Oral Med Oral Pathol. 71(3):338-42,1991.

18. Stanley HR. Pulp Capping: Conserving the Dental Pulp- Can It Be Done? Is It Worth It? Oral Surg Oral Med Oral Pathol.68:628-639,1989.

19. Tronstad L. Reaction of the Exposed pulp to dycal treatment. Oral Surg Oral Med Oral Pathol. 38(6):945-53, 1974.