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.

Evaluation of antimicrobial and thermal effects of diode laser on root canal dentin.

OBJECTIVES: The aim of this study was to evaluate the antimicrobial effects of diode laser and temperature rise on the root surface during application. MATERIALS AND METHODS: Thirty-six teeth were chemomechanically prepared and irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid, and then autoclaved and incubated with a suspension of Enterococcus faecalis. The specimens were randomly divided into three groups (n = 12): Group 1, irradiated by diode laser at 1.2 W; Group 2, irradiated by diode laser at 2 W; and Group 3, irradiated by diode laser at 3 W. The grown bacteria were counted and the mean numbers of the each test tube were determined. The temperature was measured on the external apical third of the root during laser application. The mean values of results for each group were compared using one-way analysis of variance and Tukey test. RESULTS: No significant difference was obtained among the test groups in terms of the colony counts (P > 0.05). According to the temperature changes, there was a significant difference between groups (P < 0.05). Temperature rises were 16.79°C, 10.20°C, and 6.25°C in Group 3, Group 2, and Group 1, respectively. CONCLUSION: Diode laser irradiation with 1.2 W demonstrated comparable performance with 2 W and 3 W power sets for elimination of E. faecalis from root canal with less temperature rise.