The Effect of Combined Application of Tricalcium Phosphate Containing Varnish and ER, CR: YSGG Laser on Resistance of Enamel to Caries: An In Vitro Study
Background: This study aims to investigate the efficacy of functionalized tri-calcium phosphate containing varnish combined with ER, CR: YSGG laser in preventing of enamel caries. Materials and Methods: Freshly extracted 50 sound upper first premolars teeth were divided into five groups, each group of ten samples. Group (C): only washed with deionized water. Group (V): functionalized tricalcium phosphate (fTCP) exclusively from Clinpro White Varnish. Group (L2): Er,Cr:YSGG laser (0.75 W, 8.5 J/cm2, 20 Hz, 11% air, 0% water) was irradiated. Group (V/L2): First Clinpro White varnish was applied then Er,Cr:YSGG laser. Group (L2/V): Er,Cr:YSGG laser was irradiated followed by Clinpro White varnish. Then, the pH cycling model was used to induce artificial caries. The effect was studied in vitro using Vickers microhardness test and the obtained results were statistically analyzed. The surface morphology was also examined by scanning electron microscopy. Results: there was a decreasing in surface microhardness in all groups due to the demineralization, but the least reduction in surface microhardness belonged to the group of Er,Cr:YSGG laser followed by Clinpro White varnish. Morphological changes of enamel surfaces were in relation with increasing of enamel resistance to demineralization. Conclusions: Er:Cr:YSGG Laser at energy density of 8.5 J/cm2 is indicated on decreasing the loss of enamel hardness with comparable effects to fTCP varnish application. There is an advantage in using laser at 8.5 J in combined with fTCP varnish over using laser alone and fTCP varnish alone with more benefit when laser was applied before application of fTCP varnish than the opposite.