Cytotoxic effect of Salvadora persica extracts on human gingival fibroblast cells

To assess the cytotoxic potential of Salvadora persica [S. persica] extracts on human gingival fibroblast [HGF] cells. This study was conducted between January and May 2012 in collaboration with Dental Caries Research Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia. Extracts of S. persica using hexane, ethylacetate, and ethanol as solvents at concentrations of 0.5 mg/ml and 1 mg/ml were evaluated for their cytotoxic activity against HGFs using the 3 cytotoxic assays: [3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, a tetrazole] [MTS], lactic dehydrogenase [LDH], and crystal violet [CV]. International standards for the evaluation of medical materials recommended cut-off value of cell survival >70% was used for interpretation of the results. Ethanol extract of S. persica at 0.5 mg/ml and 1 mg/ml and hexane extract of S. persica at 0.5 mg/ml were completely devoid of cytotoxic activity, hexane extract at 1 mg/ml in comparison with controls demonstrated some cytotoxicity with cell survival of 88% [p=0.045] in MTS, 86% [p=0.01] in LDH, and 88% [p=0.002] in CV assays. Similarly, ethyl acetate extract of S. persica at 0.5 mg/ml maintained cell viability of 91% in MTS, 81% in LDH, and 80% in CV assays. Maximum cytotoxicity against HGFs was observed with ethyl acetate extract of S. persica at 1 mg/ml with cell survival of 60% in MTS, 40% in LDH, and 66% CV assays [p=0.0001]. The acceptable level of cytotoxicity associated with S. persica ethanol and hexane extracts requires further evaluation to be used as irrigation solutions in endodontic treatment

Cyclic flexural fatigue resistance of the revo-s rotary nickel-titanium endodontic files

Resistance to cyclic flexural fatigue failure is an important feature of rotary nickel-titanium [NiTi] instruments. The aim of this study was to evaluate the cyclic flexural fatigue failure resistance of RevoS Shaper Universal rotary NiTi files and to compare it to two other rotary NiTi files with similar size and taper, the Hero Shaper and the ProFile. Fifteen each of Revo-S Shaper Universal, Hero Shaper, and ProFile rotary NiTi files all with the same tip diameter and taper [ISO size 25 with 0.06 taper] were assessed. The time to failure during cyclic flexural fatigue testing was recorded. The mean time to cyclic flexural fatigue failure was 96.1 + 17.3 seconds for the Revo-S Shaper Universal, 120.5 + 24.3 seconds for the Hero Shaper, and 154.6 + 14.9 seconds for the ProFile. Differences among all three groups were statistically significant [P = 0.001]. The Revo-S Shaper Universal rotary NiTi files were less resistant to cyclic flexural fatigue failure than the Hero Shaper and the ProFile files with similar tip diameter and taper

Apical accuracy of root canal fillings performed using the root ZX as the sole method of working length determination

This is an in vivo investigation that was undertaken to evaluate the apical accuracy of root canal fillings performed using the Root ZX apex locator as the sole method to determine the root canal length during root canal treatment and to compare them with conventional radiographic method. Twenty-eight root canals from ten orthodontic patients scheduled for bilateral extractions of their premolars were used in this study. One premolar received root canal therapy using the Root ZX to determine the working length without using active root canal treatment radiographs. The contra-lateral premolar was treated following routine root canal treatment procedures using multiple radiographs [pre-operative, working length, master apical file, master cone and final radiographs]. The teeth were then extracted, decalcified, cleared and the accuracy of the root filling length was evaluated. The results demonstrated that the apical accuracy of root canal fillings performed using the Root ZX only were satisfactory in 86% of the cases compared with 57% using the conventional method, however, the difference was not statistically significantly [P = 0.135]. It was concluded that both techniques produced root canal fillings with similar apical accuracy

Microbial quality of closed- and open-circuit dental unit water systems

This study was undertaken to compare microbial levels of dental units with independent water . source [closed-circuit] to dental units directly linked to municipal water system [open-circuit]. Ten dental units with a closed-circuit and ten dental units with open-circuit water systems were randomly selected for this study. Both dental unit types were supplied by municipal water and subjected to the same disinfection protocol. Water samples were collected from the distal outlet of 'the 3-in-l syringe and from the cup filler. The samples were cultured on yeast extract agar medium >.H;'for 48 hours at 37°C. The total number of colony forming units [CPU] was counted using a Darkfield Quebec Colony Counter. The results were compared using analysis of variance [ANOVA] with significance level set to p < 0.05. The mean total viable count [TVC] for the 3-in-l syringe water samples was 619 CPU ml'1 for closed-circuit water system units and 496 CPU ml'1 for open-circuit system units the difference was not statistically significant [p= 0.565]. The mean TVC for the cup filler water samples was 466 CPU ml'1 for closed-circuit system units, and 336 CPU ml-1 for open circuit system units, the difference was not statistically significant [p=0.534]. Over 50% of all the collected samples contained TVC exceeding the ADA recommended level of < 200 CPU ml[-1]. It was concluded that both dental unit types were similar in containing unacceptably high levels of microorganisms