Comparative evaluation of antimicrobial and antifungal efficacy of bioactive root-end filling materials: An in vitro study.

CONTEXT: Microorganisms are the main cause of failure of endodontic treatment. When retreatment fails periapical surgery followed by retrograde filling is done to seal the apex. A root-end filling material should have antimicrobial property as well as bioactive properties necessary for healing, repair, and regeneration of the apex. AIMS: The aim of this study was to evaluate the antibacterial and antifungal efficacy of three bioactive root-end filling materials: mineral trioxide aggregate (MTA) Plus, Biodentine, Endosequence root repair material (ERRM) against Enterococcus faecalis and Candida albicans. SUBJECTS AND METHODS: E. faecalis and C. albicans standard bacterial strains were used. 100 µl was taken from liquid cultures of E. faecalis and planted in Mueller-Hinton agar and the same amount of C. albicans was planted in Sabouraud dextrose agar by lawn culture. MTA Plus, Biodentine, and ERRM were aseptically filled into the opened pits. Following this, the media were kept in the drying oven at 37°C for 24, 48, and 72 h and the diameters of the inhibition zones were measured. STATISTICAL ANALYSIS USED: Statistical analysis was carried out by Kruskal-Wallis, Post hoc (Mann-Whitney), Friedman, and Post hoc (Wilcoxon-sign) test. RESULTS: Among the three groups, the antimicrobial activity of Biodentine against E. faecalis was statistically higher than MTA Plus and ERRM (P < 0.05). Antifungal activity of MTA Plus against C. albicans was statistically higher than Biodentine and ERRM (P < 0.05). ERRM showed the smallest inhibition zone against E. faecalis and C. albicans among the three groups (P < 0.05). CONCLUSIONS: Biodentine exhibited the greatest antimicrobial activity and MTA Plus exhibited the greatest antifungal activity among the three groups. ERRM exhibited the least antibacterial and antifungal activity among the three groups.

Evaluation of the efficacy of a novel antibiotic-steroid paste versus conventionally used intracanal antibiotic pastes and irrigating solutions against a 3-week-old biofilm of Enterococcus faecalis.

INTRODUCTION: Intracanal medicaments have been used during endodontic regenerative procedures to eradicate endodontic pathogens. AIMS: The aim of our study was (1) to evaluate the antimicrobial efficacy of a novel antibiotic-steroid paste over the regularly used calcium hydroxide (Ca (OH)2), double antibiotic paste (DAP), and modified triple antibiotic paste (M-TAP) and (2) to check the antimicrobial efficacy of irrigating solutions, Chlorhexidine (CHX), and sodium hypochlorite (NaOCl) against a 3-week-old Enterococcus faecalis (E. faecalis) biofilm. MATERIALS AND METHODS: A total of 112 human extracted teeth were contaminated with E. faecalis for a period of 21 days. A novel antibiotic-steroid paste, Ca (OH) 2, DAP, M-TAP, and a placebo were placed inside the canal, sealed, and incubated in an aerobic environment at 37°C. For irrigating solutions, each prepared sample was immersed in 1 ml of sterile saline for 1 min, followed by irrigating and immersion with 1.5% NaOCl and 2% CHX for 5 min. An antimicrobial assessment was performed at the end of 2 days and 7 days, with seven teeth from each group, for each time interval. Dentin debris collected was transferred to the respective medium for culture. After 24 h, colonies were counted using classical bacterial counting technique as colony-forming units. RESULTS: Statistical analysis revealed that the novel antibiotic-steroid paste showed a statistically insignificant difference when compared to DAP, which had the highest antimicrobial properties. CONCLUSION: This novel functional paste has antimicrobial efficacy comparable with that of DAP.

Effect of varying durations of intracanal medicament application used in regenerative endodontic treatment on the push-out bond strength of a novel cement: NeoMTA Plus.

AIM: The aim of the present study was to evaluate the effect of varying durations of intracanal medicament application used in regenerative endodontic treatment on the push out the bond strength of a novel cement-NeoMTA Plus. MATERIALS AND METHODS: A total of 60 extracted single-rooted maxillary anterior teeth were decoronated. Roots were instrumented uniformly until Peeso Reamer size #5 to simulate open apices. A total of 60 roots were then divided into four groups according to intracanal medicaments used (n = 15): Group 1: Triple antibiotic paste (TAP); Group 2: Double antibiotic paste (DAP); Group 3: Calcium hydroxide paste (CH); and Group 4 (control): No medicament. Samples were kept in saline solution for 2, 4, and 12 weeks, after which time five roots were selected randomly from each group, representing the samples of each time point. After removal of the medicaments, NeoMTA Plus was placed into 8 mm of the coronal third of the roots and samples were incubated. Roots were sectioned to obtain 2 discs per root (n = 10). A push-out test was used to measure the sealing efficacy of NeoMTA Plus. Data were analyzed using a one-way ANOVA followed by Tukey's pairwise comparisons. RESULTS: CH, DAP, and TAP application resulted in significantly lower values of the push-out bond strength of NeoMTA Plus after 12 weeks compared to 2 weeks (P < 0.05). [Table: see text] No significant differences were found between the time points in the control group (P > 0.05). [Table: see text] DAP showed lowest push-out bond strength. [Table: see text]. CONCLUSION: CH, DAP, and TAP cause an alteration in dentinal surface properties leading to negative effect on bond strength of NeoMTA Plus. The effect is more evident in DAP and as treatment time is prolonged. The type and duration of medicament application have to be monitored to achieve a maximum therapeutic value as well as to avoid compromise on the coronal seal.

"Evaluation of the antibacterial efficacy of EZLASE diode LASER on the infected root canal system:" An in vivo study.

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.

Expansion of Gutta-percha in contact with various concentrations of zinc oxide-eugenol sealer: A three-dimensional volumetric study using spiral computed tomography.

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 7(th) day and 30(th) day, which was statistically significant from the GP volume at 1(st) 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.

The effect of multiple autoclave cycles on the surface of rotary nickel-titanium endodontic files: An in vitro atomic force microscopy investigation.

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.

A comparative evaluation of the effect of 5.25% sodium hypochlorite and 2% chlorhexidine on the surface texture of Gutta-percha and resilon cones using atomic force microscope.

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.