COMPARATIVE EVALUATION OF THE EFFECT OF SALIVA SUBSTITUTE ON THE MICROHARDNESS OF THREE DIFFERENT DIRECT TOOTH COLOURED RESTORATIVE MATERIALS: AN IN VITRO STUDY

Context: In patients usingsaliva substitute (SS) which would be a suitable aesthetic restorative material. Aims: To evaluate and compare the effect of saliva substitute on the microhardness of direct tooth coloured restorative materials. Settings and Design:This is an in vitro study for evaluation of Vickers microhardness (VM) where standard uniform disc‑shaped specimens were immersed in a saliva substitute (SS) for 30 days. Methods and Material: The tooth‑colored restorative materials tested in this study were Group I- resin modified glass ionomer cement (RM-GIC), Group II-light cured fluoride releasing restorative material (Ketac N100) and Group III-light cured resin composite restorative material (Filtek Z 350 XT).Forty‑eight disc‑shaped samples, 16 of each material were prepared. Samples belonging to respective groups were randomly divided into two subgroups with 8 samples each. Subgroup A was immersed in distilled water (DW) and subgroup B in saliva substitute (SS). In addition 3 samples of group I, II and III were prepared for scanning electron microscopic examination. VM value were calculated from the table of ISO 6507 standard. Pre and post-immersion microhardness measurements were made on the same surface of all samples. Statistical Analysis Used: Normality of data obtained was tested using Kolmogorov-Smirnov and Shapiro-Wilk test, then parametric tests were used to compare the means between different groups. The level of significance was set at 5% and the p values less than 0.05 was considered statistically significant. Results: All the restorative materials when immersed in SS showed statistically significant reduction (p<0.05) in microhardness. When the restorative materials were immersed in DW there was no substantial reduction in microhardness. Light cured resin composite restorative material (Filtek Z350 XT) showed the least reduction in microhardness followed by RMGIC and Ketac N 100. Conclusion: Among the materials tested Light cured resin composite restorative material showed maximum microhardness before and after immersion in DW and SS.