Aims and Objectives:The aim of this in vivo study was to evaluate the antibacterial efficacy of a diode LASER on the infected root canal system.Methodology:A total of forty patients with infected root canals were selected. The root canals were prepared mechanically, and irrigation was done with 3% sodium hypochlorite (NaOCl). Microbiological samples were collected before LASER treatment with the help of the master apical file (MAF) to full working length for subsequent microbiological examination. The procedure was followed by laser treatment with an EZLASE diode LASER (940 nm), at different output powers. Following irradiation, samples were collected for microbiological examination. The samples were transferred to an agar plate and incubated for 48 h at 37°C. The colonies formed were then counted, and the total number of bacteria per ml before and after LASER application was assessed. Colony-forming unit (CFU/ml) was counted for Enterococcus faecalis and other bacterial flora from pretreatment and posttreatment samples that were then analyzed using the Kruskal–Wallis test and Mann–Whitney U-test.Results:The highest power of laser used (1.95 W) had resulted in maximum reduction of bacterial flora and E. faecalis counts.Conclusions:Combination therapy consisting of irrigation using NaOCl and LASER irradiation, especially at high output power was an effective treatment option for a reduction in E. faecalis as well as other bacterial flora from the root canal system.

Aims:To observe and study the effect of multiple autoclave sterilization cycles, on the surface of nickel-titanium (NiTi) files.Materials and Methods:The file used for this study was the Mtwo file (VDW) and ProTaper (Dentsply). The apical 5 mm of the files were attached to a silicon wafer and subjected to autoclave cycles under standardized conditions. They were scanned with an AFM after 1, 5, and 10 cycles. The unsterilized files were used as control, before start of the study. Three vertical topographic parameters namely maximum height (MH), root mean square (RMS) of surface roughness, and arithmetic mean roughness (AMR)were measured with the atomic force microscope (AFM). Analysis of variance along with Tukey's test was used to test the differences.Results:The vertical topographic parameters were higher for both the files, right after the first cycle, when compared with the control (P < 0.01). The surface roughness increased sharply for Mtwo when compared to ProTaper, though ProTaper had a rougher surface initially.Conclusions:The study confirmed that the irregularities present on the surface of the file became more prominent with multiple autoclave cycles, a fact that should be kept in mind during their reuse.

Aims & Objectives:The purpose of this study was to investigate the effects of 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) on Gutta-percha and Resilon cones using an atomic force microscope (AFM).Materials and Methods:Gutta-percha cones (n = 15) and Resilon cones (n = 15) were cut 3 mm from their tip, attached to a glass slide with cyanoacrylate glue and immersed in 5.25% NaOCl and CHX for 1, 5, 10, 20 and 30 min. Five each of Gutta-percha and Resilon cones not treated with any disinfectant were used as control. The analysis of the surface topography was performed on the region between 1 and 2 mm from the tip using the AFM. The root mean square (RMS) parameters for contact mode imaging were measured. The differences between RMS values were tested by SPSS-16.0 version statistical software [IBM SPSS (Statistical Product and Service Solutions) Data Software, Chicago, US] using Kruskal-Wallis ANOVA, Mann-Whitney U-test and Wilcoxon matched pairs test.Results:There was no deterioration in the surfac e topography of Gutta-percha and Resilon when treated with 2% CHX in comparison to baseline (P < 0.05). Resilon exhibited no deterioration in topography when immersed in 5.25% NaOCl. There was a significant decrease in the mean RMS values of Gutta-percha treated with NaOCl from the control at time intervals of 1, 5, 10, 20 and 30 min.

Aim:The purpose of this study was to evaluate the three-dimensional expansion of Gutta-percha (GP), at various powder/liquid ratios, of a zinc oxide-eugenol (ZOE)-based sealer using spiral computed tomography (SCT).Materials and Methods:Thirty-five freshly extracted human mandibular premolars were selected for this study. Cleaning and shaping were performed in all the teeth initially with hand K-files up to #25 and finally with RaCe rotary instruments (25/06). Teeth were randomly divided into five groups of 7 teeth each. Specimens were scanned using SCT. They were then viewed both cross-sectionally and longitudinally, with a constant thickness of 1 mm/slice. The volume of root canal in each tooth was estimated. Obturation was performed by GP points (25/04) and ZOE-based root canal sealer in all groups with different powder-liquid ratio. Groups 1, 2, 3, and 4, had powder/liquid ratio of 1:1, 1:2, 1:3, and 1:4, respectively, while in the control group, no sealer was used. The obturation was performed by sealer coated single cone GP. A second SCT scan was performed to determine the volume of GP and sealer in all four groups 1 day after obturation. The third and fourth SCT scans were taken 7 and 30 days after obturation, respectively. The mean volume of GP per group was calculated. Data were statistically analyzed using one-way ANOVA. Inter-group comparisons were done using Scheffe post hoc multiple comparisons test.Results:All groups with sealer showed expansion of GP at both 7th day and 30th day, which was statistically significant from the GP volume at 1st day. Groups 2 and 3 with powder/liquid ratio of 1:2 and 1:3 gave the highest mean volume values during 30 days period and showed significant expansion in comparison with Groups 1 and 4 with powder/liquid ratio of 1:1 and 1:4, respectively.Conclusion:Increasing the ratio of eugenol in sealer resulted in the volumetric expansion of GP. However, further studies should be performed to confirm the expansion of GP, leading to the achievement of fluid impervious seal.

For patients who require removal of anterior teeth due to periodontal problems there are a multitude of treatment considerations. Using the natural tooth as a pontic offers the benefits of being the right size, shape and color. This paper describes the immediate replacement of an anterior tooth using a preimpregnated fiber-reinforced composite with the natural tooth as the pontic. The abutment teeth can be preserved with minimal or no preparation, thus keeping the technique reversible, and can be completed at the chair side thereby avoiding laboratory costs. It can be used as an interim measure or as a definitive prosthesis.