The effect of Nd:YAG laser radiation on hydroxyapatite and investigating silver nitrate solution deposition in deciduous teeth

Abstract

Background: The regulation of the demineralization–remineralization balance is a key to the dental caries prevention, therefore use of wide range of fluoridated and non-fluoride anti-caries agents and methods or combination of them has been postulated. Current evidence shows that treatment of enamel surface by laser radiation is effective in preventing the development of primary caries, as well as the treatment of tooth enamel surfaces using silver nitrate in preventing the progress of enamel caries. Materials and methods: In this laboratory study, 36 healthy upper and lower deciduous teeth were used. To make the samples, plastic cylindrical molds were prepared and self-curing acrylic resin was poured into the molds. Cut samples of enamel blocks were immersed in demineralizing solution at 37°C for 48 hours. In the laser group, the surface of the samples was treated with a Nd:YAG laser with a wavelength of 1064 nm. In the silver nitrate group, the samples were smeared with the solution with a microbrush and remained untouched for 5 minutes. All samples were washed with deionized water and left in artificial saliva for the remaining time (approximately 20 hours per day). The mineral content (calcium and phosphorus) and silver of the samples were evaluated using scanning electron microscopy (SEM) and X-ray energy diffraction spectroscopy (EDX). In order to compare the weight percentage of phosphorus, calcium and microhardness between the studied groups, one-way analysis of variance (ANOVA) was used and spss version 19 software was used to analyze the data. Result: The results of one-way analysis of variance showed that the difference in the average weight percentage of phosphorus between the studied groups was statistically significant (p-value=0.002), but the difference in the average weight percentage of calcium (p-value=0.096) and microhardness (p-value=0.057) was not statistically significant (the p-value obtained in microhardness may become significant with some increase in the sample size) . SEM evaluation confirmed the above results. EDX studies also showed the deposition of silver particles on tooth enamel. Conclusion: The use of Nd:YAG laser is recommended as a method to prevent caries in primary teeth, and also the deposition of silver nitrate solution in primary teeth is observed and confirmed.