Objectives: This study evaluated the effect of 20% amorphous calcium phosphate nanoparticles loaded in chlorhexidine as an intra-canal medicament on root canal dentin microhardness.
Methods: 30 human permanent single rooted teeth were used in this study. Teeth were decoronated and roots were split longitudinally into two halves, the better half was kept and the other was discarded (30 specimens). The specimens were randomly divided into 3 groups according to the medicament used: 20% amorphous calcium phosphate nanoparticles in chlorhexidine (NACP+CHX), 2% chlorhexidine (CHX) and calcium hydroxide (Ca(OH)2). Each medicament was applied for two weeks immediately after initial baseline microhardness determination. The initial baseline microhardness determination utilized Vickers indenter under a 200-g load and a 15-second dwell time. Post treatment microhardness values were obtained utilizing the same settings. The change in radicular microhardness was calculated as a percentage. Data were statistically analyzed utilizing 1-way analysis of variance (P=.05) and post hoc Tukey test for the multiple comparisons at the same level of significance. The difference between the pre-treatment and the post-treatment microhardness values were statistically analyzed utilizing t-test with a P < .05.
Results: 20% amorphous calcium phosphate nanoparticles in chlorhexidine was the only medicament to result in a statistically significant increase in radicular dentin microhardness, while 2% chlorhexidine and calcium hydroxide resulted in a statistically significant decrease, with calcium hydroxide having the most detrimental effect.
Conclusion: On the contrary of 2% chlorhexidine and calcium hydroxide, 20% amorphous calcium phosphate nanoparticles in chlorhexidine demonstrated reinforcing effect on radicular dentin microhardness.