evaluating the effect of sumac extract on dentine micro-hardness during ph cycling

Statement of the problem: although sumac extract (se) is reported as a collagen cross linker, the available data regarding its effect on the dentine micro-hardness is quite sparse.purpose: therefore, the aim of this study includes evaluating the effect of different concentrations of se on dentine micro-hardness comparing to grape seed extract (gse).materials and method: in this experimental study, the gse was purchased from available market and convert to 5% solution. meanwhile the 5, 10, and 20% of se solutions were prepared experimentally. the base line micro-hardness of 60 samples (30 premolars divided to buccal and lingual segments) was recorded triplicate for each specimen and they were randomly divided into 5 groups (four abovementioned experimental solutions and de-ionized water as negative control). for 35 consecutive days, each sample was twice ph cycled and treated by solutions. ultimately, the final micro-hardness was recorded triplicate again for each sample and the numerical data was compared with each other using one-way anova and tukey hsd post hoc tests (α=0.05).results: the mean±sd values of micro-hardness for the groups was recorded as 54.45± 13.4, 65.65±18.5, 39.57±2.26, 41.13±1.66 and 43.79±4.96 at base line and 10.4±0.99, 11.85± 0.75, 10.16±1.84, 8.48±1.16 and 6.31±1.01 at final stage for control, gse 5%, se 5%, se 10% and se 20% respectively. there was no significant difference among the micro-hardness of the groups before treatment (p= 0.369). however, after experimental treatment, there was significant difference between the groups (p= 0.024) while in pairwise comparison just two groups (gse 5% and se 20%) had significant difference with each other (p= 0.017).conclusion: the efficacy of se was reversely related to its concentration. moreover, neither gse nor se had significant effect on dentine micro-hardness after 35 day ph cycling.