Occluding Efficiency of Different Desensitizing Agents and Er,Cr:YSGG Laser on Dentin Tubules.

PURPOSE: This study aimed to evaluate the effects of two desensitizers and the Er,Cr:YSGG laser on human dentin tubules, applied alone or in combination. METHODS: Ninety-six dentin specimens were obtained from extracted third molars and divided into six groups: Group 1: no-treatment (Control); Group 2: nano-hydroxyapatite desensitizer (NhapD); Group 3: NhapD+Er,Cr:YSGG laser (L); Group 4: Er,Cr:YSGG laser (L); Group 5: glutaraldehyde desensitizer (GD); and Group 6: GD+L, respectively. All specimens were evaluated using scanning electron microscopy. The diameter and the number of open dentin tubules, the tubules' occluding ratio, and the mineral coverage area were measured via the Image J software at 2000× magnification. Atomic force microscopy was used to determine the blocking mechanism of desensitizing treatments and the surface morphology of dentin specimens. One-way ANOVA and Tukey tests were used for statistical analysis. RESULTS: The number of open tubules and the mean diameter of tubules for all treatment groups showed statistically significant differences from the control group The NhapD+L group had a significantly lower number of open tubules than the L and GD groups. The NhapD+L and L groups significantly had higher occluding ratios than the other groups. CONCLUSIONS: The present study showed that the Er,Cr:YSGG laser alone was effective in terms of tubule occlusion and also contributed to increasing the occluding ratio of nano-hydroxyapatite. It may be recommended to use the Er,Cr:YSGG laser with nano-hydroxyapatite desensitizers to achieve effective tubule occlusion.

Effects of Bioactive Pulp-capping Materials on Cell Viability, Differentiation, and Mineralization Behaviors of Human Dental Pulp Stem Cells In Vitro.

PURPOSE: The objective of this study was to assess the effect of bioactive pulp-capping materials on human dental pulp stem cell (hDPSC) behavior in terms of cell viability and bioactivity via mineralization potential. METHODS AND MATERIALS: Nanoparticles of 58S5 bioactive glass (nBG) powder were elaborated by a sol-gel process. Primer hDPSCs were cultured with experimental nBG, Biodentine, TheraCal LC, and ProRoot mineral trioxide aggregate (MTA) extracts. Cell viability was measured for 1, 3, and 7 days by water-soluble tetrazolium salts (WST-1) assay. Expression of mineralization-related marker genes (dentin sialophosphoprotein [DSPP] and osteocalcin [OCN]) was quantified by a real-time polymerase chain reaction. Detection of DSPP protein expression in hDPSCs was also assessed by western blotting. Alizarin red staining was used to detect the formation of mineralized nodules, and alkaline phosphatase (ALP) activity was quantified by a photometric method (days 7 and 14). All data were statistically analyzed with a one-way analysis of variance (ANOVA) and Tukey's post-hoc test (p<0.05). RESULTS: The cell viability of hDPSCs in all groups decreased except for nBG, and the lowest cell viability was determined in TheraCal LC at all incubation times. nBG and MTA showed significantly higher ALP activity than the control group. The tested materials elevated the calcium nodule form of hDPSCs except for TheraCal LC. The highest DSPP expression was seen in nBG for both incubation times. CONCLUSION: nBG promotes differentiation and mineralization of hDPSCs at a higher rate than other bioactive pulp-capping materials tested.