Effects of three different minimally invasive approaches on microhardness and mineral density of primary tooth dentin surface

Objective: The aim of this study was to evaluate the effects of three different minimally invasive approaches applied to artificially demineralized primary dentin surfaces on remineralization, using microhardness testing and mineral density analysis. Methods: A total of 76 extracted primary molars were used. The teeth were divided into three main groups representing GF, ART, and GMART approaches. For Vickers microhardness measurements, 60 teeth were selected (n=20 per group). Teeth in the treatment groups were evaluated at four different time points: baseline (T0), after pH cycling (T1), after treatment application (T2), and after additional pH cycling (T3). Repeated measurements were obtained from the same specimens, and changes in hardness were recorded. For mineral density determination, SEM-EDX analysis was performed on n=4 specimens per treatment group, as well as on n=2 specimens each from the T0 and T1 groups. Mapping and line scan analyses were conducted on longitudinal surfaces. Results: In all groups, a significant decrease in microhardness values was observed at the T1 stage, and no statistically significant difference was found between the groups at T0 and T1 stages. At the T2 stage, all groups showed a significant increase compared to the T1 values. The highest mean hardness value was recorded in the GF group (39,54 ± 3,13 VHN), while the lowest mean hardness value was recorded in the ART group (34,41 ± 3,09 VHN). At the T3 stage, all groups exhibited a decrease compared to the T2 stage. The highest mean value was found in the GMART group (36,27 ± 3,64 VHN), while the lowest mean value was observed in the ART group (26,72 ± 2,35 VHN). SEM-EDX analyses showed that the Ca/P ratio at the T2 stage was higher compared to the T1 stage in all groups, and the presence of Ag element was detected in the GF and GMART groups. Conclusion: It was observed that the groups in which GF was applied exhibited significantly higher microhardness values compared to ART. According to the results of this study, applying these methods may be considered a more suitable option for patient groups with high caries risk and cooperation difficulties. Keywords: silver diamine fluoride, atraumatic restorative treatment, silver-modified atraumatic restorative treatment, microhardness analysis, mineral density analysis