Evaluation Of Effect Of Two Different Functionalized Nanoparticle Photodynamic Therapy On Nanohardness Of Root Dentin-An In Vitro Study.

Abstract Introduction The aim of this study was to evaluate the effect of functionalized nanoparticle photodynamic therapy on Nano hardness of root dentin Methodology Fifty single rooted lower premolars were decoronated and sectioned into two halves. Then the samples were embedded horizontally in to the acrylic resin to expose the dentin surface. Baseline nanohardness was done at midroot level using a Nanohardness tester. Exposed dentin surfaces were immersed in the following irrigating solutions • Group 1: 1 ml of Methylene blue loaded poly lactic acid (MB-PLGA np) activated with 660 nm for 10 minutes • Group 2: 1 ml of Chitosan conjugated Rose Bengal (CSRB-np) activated with 540 nm for 10 minutes • Group 3: 1 ml of 2.5 % sodium hypochlorite for 10 minutes + 1 ml of 17% EDTA for 1 minute • Group 4: 1 ml of 2.5 % sodium hypochlorite for 10 minutes + 1 ml of 17% EDTA for 1 minute + 1 ml of 2% chlorhexidine for 1 minute. • Group 5: 1 ml of 0.9% Saline for 10 minutes. Post treatment nanohardness testing was done and results were analyzed statistically Results In general, all the samples in their respective groups had significant change in nanohardness following immersion in irrigant solutions except in NaOCl + EDTA and saline group. CSRB-np and PLGA-MBnp showed increased nanohardness (P = 0.005 and P = 0.007 respectively). Whereas NaOCl + EDTA + CHX showed decrease in nanohardness (P = 0.04). With regards to Modulus of elasticity (MOE), CSRB-np showed significant difference (P = 0.002) compared to the other groups. MOE increased in CSRB-np and PLGA-MBnp while it decreased in all the other groups. Conclusion In this study, the improvement of nanohardness and modulus of elasticity following the immersion of root dentin in CSRB-np solution was demonstrated