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Aim To compare the antimicrobial activities of Activ Point ( Roeko, Langenau, Germany), Calcium Hydroxide Plus Point ( Roeko, Langenau, Germany), calcium hydroxide, 1% chlorhexidine gel and bioactive glass (S53P4) against Enterococcus faecalis and Streptococcus mutans. Methodology One hundred and twenty extracted single-rooted human teeth were used. After removing the crowns, root canals were prepared by using the Protaper rotary system. Following autoclave sterilization, root canals were incubated at 37 °C with E. faecalis ATCC 29212 and S. mutans RSHM 676 for 1 week. The specimens, which were divided into five treatment groups for each microorganism according to the intracanal medicament used, were tested in 10 experimental runs. In each experimental run, 10 roots were included as treatment, one root as positive control and one root as sterility control. Sterile paper points were utilized to take samples from root canals after the incubation of teeth in thioglycollate medium at 37 °C for 1 week. Samples taken from teeth by sterile paper points were inoculated onto sheep blood agar, and following an overnight incubation, the colonies grown on sheep blood agar were counted and interpreted as colony-forming units. Results were tested statistically by using Kruskal- Wallis and Conover's nonparametric multiple comparison tests. Results CHX gel ( P < 0.001 and P < 0.001), Activ Point ( P = 0.003 and P = 0.002) and Ca( OH)2 ( P = 0.010 and P = 0.005) were significantly more effective against E. faecalis than that of Ca( OH)2 Plus Point and bioactive glass, respectively. On the other hand, compared with Ca( OH)2, CHX gel ( P < 0.001), and Activ Point ( P < 0.001), bioactive glass ( P = 0.014) produced significantly lower colony counts of S. mutans. When compared with the positive control, treatment with Ca( OH)2 Plus Point ( P = 0.085 and P = 0.066) did not produce significantly lower colony counts of E. faecalis and S. mutans, respectively. Conclusions Compared with the medicaments having an antimicrobial effect because of their alkaline pH, the medicaments containing chlorhexidine were effective against both E. faecalis and S. mutans. [ABSTRACT FROM AUTHOR]

Antiseptics used in endodontics for disinfection purposes include root canal dressings and irrigants. Osmotic shock is known to cause the alteration of microbial cell viability and might have a role in the mechanism of action of root canal antiseptics. The aim of this review was to determine the role of osmolarity on the performance of antiseptics in root canal treatment. A literature search using the Medline electronic database was conducted up to 30 May 2013 using the following search terms and combinations: 'osmolarity AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmolality AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmotic AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmosis AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; sodium chloride AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm'. Publications were included if the effects of osmolarity on the clinical performance of antiseptics in root canal treatment were stated, if preparations with different osmolarities values were compared and if they were published in English. A hand search of articles published online, 'in press' and 'early view', and in the reference list of the included papers was carried out following the same criteria. A total of 3274 publications were identified using the database, and three were included in the review. The evidence available in endodontics suggests a possible role for hyperosmotic root canal medicaments as disinfectants, and that there is no influence of osmolarity on the tissue dissolution capacity of sodium hypochlorite. There are insufficient data to obtain a sound conclusion regarding the role of hypo-osmosis in root canal disinfection, or osmosis in any further desirable ability. [ABSTRACT FROM AUTHOR]

Aim To determine the antimicrobial efficacy of ozonated water, gaseous ozone, sodium hypochlorite and chlorhexidine in human root canals infected by Enterococcus faecalis. Methodology Thirty human maxillary anterior teeth were prepared and inoculated with E. faecalis for 60 days. Eppendorf tubes were connected to the coronal portion of the teeth. Urethane hoses were attached to the tubes and to the entrance of a peristaltic pump. The exit of the apparatus corresponded to the apical portion of the root canals. The test irrigating solutions were ozonated water, gaseous ozone, 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine that circulated at a constant flow of 50 mL min−1 for 20 min. Samples from the root canals were collected and immersed in 7 mL Letheen Broth (LB), followed by incubation at 37 °C for 48 h. Bacterial growth was analysed by turbidity of the culture medium and subculture on a specific nutrient broth. A 0.1 mL inoculum obtained from LB was transferred to 7 mL of brain heart infusion and incubated at 37 °C for 48 h. Bacterial growth was checked by turbidity of the culture medium carried out in triplicate. Results No solution used as an irrigant over a 20-min contact time demonstrated an antimicrobial effect against E. faecalis. Conclusion The irrigation of infected human root canals with ozonated water, 2.5% NaOCl, 2% chlorhexidine and the application of gaseous ozone for 20 min was not sufficient to inactivate E. faecalis. [ABSTRACT FROM AUTHOR]

Aim To determine in vivo, the degree of microbial reduction after chemo-mechanical preparation of human root canals containing necrotic pulp tissue when using two endodontic irrigating reagents, sodium hypochlorite (NaOCl) or chlorhexidine gel (CHX). Methodology Thirty-two single rooted teeth with necrotic pulp were divided into two groups. One group ( n = 16) was irrigated with 2.5% NaOCl, whilst the other group ( n = 16) was irrigated with 2% CHX gel. Assessment of the bacterial load was accomplished by use of real-time quantitative-polymerase chain reaction (RTQ-PCR) directed against the small subunit ribosomal DNA using the SYBRGreen and TaqMan formats. Statistical analysis was performed using the Mann–Whitney test. For contrast, bacterial load was also determined by traditional culture techniques. Results The bacterial load was reduced substantially in both groups (over 96%). However, using RTQ-PCR the bacterial load before and after chemo-mechanical preparation was greater when compared with evaluation using colony forming units (CFU). Furthermore, as measured by RTQ-PCR, the bacterial reduction in the NaOCl-group (SYBRGreen 99.99%; TaqMan: 99.63%) was significantly greater ( P < 0.01) than in the CHX-group (SYBRGreen 96.62%; TaqMan: 96.60%). According to culture technique 75% of cases were free of bacteria after chemo-mechanical preparation in the NaOCl-group, whilst 50% of cases were bacteria free in the CHX-group. Conclusion NaOCl has not only a higher capacity to kill microorganisms but is also more able to remove cells from the root canal. [ABSTRACT FROM AUTHOR]

Valois CRA, Silva LP, Azevedo RB. Effects of 2% chlorhexidine and 5.25% sodium hypochlorite on gutta-percha cones studied by atomic force microscopy. International Endodontic Journal, 38, 425–429, 2005. To compare the effects of 2% chlorhexidine (CHX) and 5.25% sodium hypochlorite (NaOCl) on gutta-percha (GP) cone structure using atomic force microscopy (AFM). Two standardized GP cones were sectioned 3 mm from the tip, attached to a glass base and immersed in 2% CHX or 5.25% NaOCl for 1, 5, 10, 20 and 30 min. Untreated GP cones were used as control. Topography and elasticity analyses were performed on 12 different regions located between 1 and 2 mm from the tip. Root mean square (RMS) parameters for contact mode imaging and force modulation microscopy variations were measured. The differences between RMS values were tested byanova with Fisher's protected LSD test for multiple comparisons. There was no deterioration in the topography and physical properties studied when 2% CHX was used in comparison with the control ( P < 0.05). The RMS parameter for topography increased after 10 min of 5.25% NaOCl exposure in comparison with the control ( P < 0.05). In addition, 5.25% NaOCl increased the elasticity of the GP cone after an immersion time of 1 min in comparison with the control ( P < 0.05). Two per cent CHX did not change GP cone structure following up to 30 min exposure. Conversely, 5.25% NaOCl caused elastic changes after 1 min exposure. [ABSTRACT FROM AUTHOR]

During the 1970s there has been a resurgence of interest in endodontic microbiology. Newer findings have also appeared on both the mechanisms of host resistance to microbiological factors and the relative importance of various microbiological factors in inducing disease. In considering these findings, this article reviews the following topics: the microbiological flora, anaerobic culture techniques, intracanal medicaments and irrigants, sterilization and asepsis, host-parasite interactions, immunological aspects, antibiotics, and pathways of infection.