Evaluation of surface properties and microhardness changes of permanent tooth surfaces on which agents used in the treatment of initial caries were applied after immersed in different cariogenic solutions

Aim: In today's modern dentistry practices, minimally invasive techniques are preferred over traditional treatment techniques. For this reason, the treatment of caries lesions that have not yet formed cavitation and the evaluation of the effectiveness of these treatments are important. The primary aim of this study is to compare the changes in microhardness values in enamel tissue caused by the materials used in the initial caries treatment under in vitro conditions and to evaluate the SEM/EDS images. The secondary aim is to compare the changes in microhardness values after aging the teeth in various drinks to which the relevant treatment materials were applied and to evaluate the SEM/EDS images. Material and Methods: 90 extracted caries-free human permanent premolars were used in the study. The samples were randomly divided into 3 groups. The initial microhardness of the groups was measured and they kept in demineralizing solution for 48 hours to create an artificial caries lesion. Sodium Fluoride varnish (SFV) was applied to Group 1, Silver Fluoride (SF) was applied to Group 2, and Resin Infiltrant (RI) was applied to Group 3. Which therapeutic materials were applied to were immersed in artificial saliva solution (control group), milk and cola by creating daily exposure habits. Microhardness values were recorded on the 7th and 14th days after exposure to liquids, SEM/EDS images were taken. Results: The RI applied group was the only group that was the closest to the initial microhardness and had no statistically significant difference with the initial microhardness (pholm=0.06). Although the enamel samples in the fluoride varnish and GF groups showed an increase in microhardness after application, it was statistically significantly lower compared to the initial microhardness (pholm<0.001). Aging with milk increased the surface microhardness statistically significantly in all groups (Fluoride varnish; pholm<0.001, GF; pholm=0.050, RI; pholm<0.001). It was determined that cola caused a statistically significant decrease in microhardness values in all groups (pholm <0.001). While SEM images prove the erosive effects of cola on enamel, the enamel surface that showed the most resistance to these effects was the group in which RI material was applied. Conclusion: According to the results obtained from our study conducted under in vitro conditions; RI, SFV and SF compounds can be used in the treatment of incipient caries, and the best efficacy was shown by resin infiltration treatment. However, it has been found that conventional dietary habits can have positive or negative effects on the treatment process. Therefore, the results obtained from our study suggest that current minimally invasive treatment materials, together with dietary habits, can provide successful results in the treatment of incipient caries. Nevertheless, these findings, which were determined in vitro, should be supported by in vivo, randomized controlled clinical studies. Keywords: Initial caries, Resin infiltration, Silver diamine fluoride, Silver fluoride, Sodium fluoride varnish