Kasraei S, et al. Restor Dent Endod. 2014 May;39(2):109-114. https://doi.org/10.5395/rde.2014.39.2.109

Objective: Dental caries is one of the most common infectious diseases worldwide. Saliva has many functions in the oral cavity and is the first line defense against dental caries. Oxidative stress can affect initiation and progression of many inflammatory and infectious diseases such as dental caries. Thus the aim of this study was to evaluate the relationship between total antioxidant capacity (TAC) of saliva and dental caries. Study Design: 100 healthy high school students (50 female and 50 male) with age range of 15 -17 years were randomly selected, divided to four groups. Unstimulated whole saliva specimens were collected at the morning. TAC of saliva was evaluated by spectrophotometric assay. Statistical comparisons were performed using Student’s t-test, by SPSS 13. Results: The level of TAC was significantly higher in the saliva of caries active group relative to the caries free subjects. Statistical analysis for male and female groups showed a statistically significant reduction of TAC level in female group. Conclusion: TAC was higher in caries active group. Thus this result showed that total antioxidant capacity may influence in dental caries and activity can be measured by salivary factors and this may be helpful in preventive dentistry.

Kasraei S, et al. Restor Dent Endod. 2014 Nov;39(4):296-302. http://dx.doi.org/10.5395/rde.2014.39.4.296

Aim. Several new bioactive compounds were recently introduced to the market with favorable ion release, tooth remineralization, and alkalizing potential. This study sought to compare the phosphate ion release and alkalizing potential of three bioactive materials in comparison with composite resin. Methods. Thirty-six discs (2×6mm) were fabricated from Fuji II LC resin modified glass ionomer (RMGI), Activa BioActive, Cention N, and Z250 composite in plastic molds. The specimens were stored in distilled water for 24 and 48h and 6 months. Half of the specimens were used to assess the phosphate ion release while the other half were used to assess the alkalizing potential 1h after pH drop from 6.8 to 4. Phosphate ion release was quantified by a spectrophotometer while the pH value was measured by a pH meter. Data were analyzed using two-way ANOVA, one-way ANOVA, and Tukeys HSD test (for pairwise comparisons) at 0.05 level of significance. Results. At 24h, the maximum phosphate ion release in distilled water occurred in the Fuji II LC group followed by Cention N, Activa BioActive, and Z250. At 6months, Cention N followed by Activa BioActive showed higher phosphate ion release than Fuji II LC and Z250. No significant difference was noted between Activa BioActive and Cention N at any time point. All materials, except for Z250, increased the pH of the environment. Fuji II LC had maximum alkalizing effect at all time points followed by Cention N and Activa BioActive. Conclusion. Use of bioactive compounds is a promising method to ensure phosphate ion release, and can have a positive effect on tooth remineralization over time. Also, bioactive compounds can alkalize an acidic environment.

Incorporation of silver nanoparticles into composite resins is recommended for their reported antibacterial properties, but this incorporation can affect the wettability of such materials. Therefore, this study evaluated the effect of nano-silver addition to silorane-based and methacrylate-based composites on their contact angle. Nano-silver particles were added to Z250 (methacrylate-based) and P90 (silorane-based) composites at 0.5% and 1% by weight. The control group had no additions. SEM-EDX analysis was performed to confirm the homogeneity of the nano-silver distribution. Seventy-two composite discs were prepared and standardized to the identical surface roughness values, and then distributed randomly into 6 groups containing 12 samples each (N = 12). Two random samples from each group were observed by atomic force microscopy. Distilled water contact angle measurements were performed for the wettability measurement. Two-way ANOVA, followed by the Tukey-HSD test, with a significance level of 5%, were used for data analysis. It was observed that wettability was significantly different between the composites (p = 0.0001), and that the addition of nano-silver caused a significant reduction in the contact angle (p = 0.0001). Wettability varied depending on the concentration of the nano silver (p = 0.008). Silorane-based composites have a higher contact angle than methacrylate-based composites. Within the limitations of this study, it can be concluded that the addition of 0.5% nano-silver particles to the composites caused a decrease in the contact angle of water.