RESUMO
Context: The resin-dentin interface is less durable, which reduces the longevity of tooth-colored restorations. To encounter this shortcoming, the use of nanotechnology to mimic biomineralization proves beneficial. Aims: This study was conducted to evaluate the effect of remineralization with strontium-doped nanohydroxyapatite (Sr-nHAp) with chitosan on shear bond strength of resin composite to dentin. Materials and Methods: Sixty five extracted human premolars were divided into five groups (n = 13) based on remineralization protocol as: Group A - 20% (Sr-nHAp) with chitosan, Group B - 10% (Sr-nHAp) with chitosan, Group C - 20% (Sr-nHAp) with simulated body fluid, Group D - 10% (Sr-nHAp) with simulated body fluid, and Group E - control. Following bonding, resin composite of specified dimension was built and was subjected to shear bond strength test after 24 h and 1 week using Universal Testing Machine, and mode of failure was assessed. ANOVA and paired sample t-test were used for analyzing the data, and the level of significance was set at 5%. Results: The highest value of shear bond strength was obtained from Group A after aging for a week, and there is a significant increase in the value of all the groups as compared to the control group after 1 week of storage than 24 h. Conclusions: Remineralization with Sr-nHAp and chitosan has positively improved the bond strength of resin to dentin at the end of 1 week.
RESUMO
AIMS: A study was done to evaluate the antimicrobial efficacy of sodium hypochlorite (NaOCl) and photoactivated disinfection (PAD) on Enterococcus faecalis. SETTINGS AND DESIGN: Random sampling, in-vitro study. SUBJECTS AND METHODS: Access opening and biomechanical preparation were performed on fifty freshly extracted mandibular second premolars. The specimens were sterilized; 15 µm of E. faecalis was inoculated into each canal and incubated at 36°C for 24 h. Later, specimens were randomly divided into two groups of fifty each and following procedures was carried out: (i) conventional irrigation with 2.25% NaOCl (ii) PAD using diode laser, and toluidine blue photosensitizer. Samples were collected from each canal using sterile paper points which were deposited in brain heart infusion broth, and microbiological evaluation was carried out. STATISTICAL ANALYSIS USED: Student's t-test was used to find the significant difference in the reduction of colony forming unit (CFU) between the groups. RESULTS: The mean CFUs of the two groups showed statistically significant difference (P = 0.001). Improved antibacterial efficacy was seen with PAD group compared to conventional NAOCL irrigation. CONCLUSIONS: NaOCl alone was not effective in eliminating E. faecalis completely from the root canals. PAD compared to conventional irrigation showed the best results in removing E. faecalis from root canals.