https://www.rpcendo.com/vItPfwcx/PDF3.pdf

Enterococcus faecalis: Its Role in Root Canal Treatment Failure and Current Concepts in Retreatment

Bacteria have been implicated in the pathogenesis and progression of pulp and periapical diseases. The primary aim of endodontic treatment is to remove as many bacteria as possible from the root canal system and then to create an environment in which any remaining organisms cannot survive. This can only be achieved through the use of a combination of aseptic treatment techniques, chemomechanical preparation of the root canal, antimicrobial irrigating solutions and intracanal medicaments. The choice of which intracanal medicament to use is dependent on having an accurate diagnosis of the condition being treated, as well as a thorough knowledge of the type of organisms likely to be involved and their mechanisms of growth and survival. Since the disease is likely to have been caused by the presence of bacteria within the root canal, the use of an antimicrobial agent is essential. Many medicaments have been used in an attempt to achieve the above aims but no single preparation has been found to be completely predictable or effective. Commonly used medicaments include calcium hydroxide, antibiotics, non-phenolic biocides, phenolic biocides and iodine compounds. Each has advantages and disadvantages, and further research is required to determine which is best suited for root canal infections.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1834-7819.2007.tb00527.x

The use of calcium hydroxide, antibiotics and biocides as antimicrobial medicaments in endodontics

Interaction between Sodium Hypochlorite and Chlorhexidine Gluconate

In the past few years, Enterococcus faecalis has been the focus of increased interest both in medicine and dentistry. A recognized pathogen in post-treatment endodontic infections, E. faecalis is frequently isolated both in mixed flora and in monocultures. E. faecalis is probably the species that can best adapt to and tolerate the ecologically demanding conditions in the filled root canal. Eradication of E. faecalis from the root canal with chemomechanical preparation and using disinfecting irrigants and antibacterial dressings is difficult. In this article, the different factors that make E. faecalis a potential problem in medicine and dentistry are summarized, with special focus on the role of E. faecalis in post-treatment endodontic disease.

Enterococcus faecalis– the root canal survivor and ‘star’ in post-treatment disease

Chemical auxiliary substances (CAS) are essential for a successful disinfection and cleanness of the root canals, being used during the instrumentation and if necessary, as antimicrobial intracanal medicaments. Different CAS have been proposed and used, among which sodium hypochlorite (NaOCl), chlorhexidine (CHX), 17% EDTA, citric acid, MTAD and 37% phosphoric acid solution. CHX has been used in Endodontics as an irrigating substance or intracanal medicament, as it possesses a wide range of antimicrobial activity, substantivity (residual antimicrobial activity), lower cytotoxicity than NaOCl whilst demonstrating efficient clinical performance, lubricating properties, rheological action (present in the gel presentation, keeping the debris in suspension); it inhibits metalloproteinase, is chemically stable, does not stain cloths, it is odorless, water soluble, among other properties. CHX has been recommended as an alternative to NaOCl, especially in cases of open apex, root resorption, foramen enlargement and root perforation, due to its biocompatibility, or in cases of allergy related to bleaching solutions. The aim of this paper is to review CHX's general use in the medical field and in dentistry; its chemical structure, presentation form and storage; mechanism of action; antimicrobial activity including substantivity, effects on biofilms and endotoxins, effects on coronal and apical microbial microleakage; tissue dissolution ability; interaction with endodontic irrigants; effects on dentin bonding, metalloproteinases and collagen fibrils; its use as intracanal medicament and diffusion into the dentinal tubules; its use as disinfectant agent of obturation cones; other uses in the endodontic therapy; and possible adverse effects, cytotoxicity and genotoxicity.

/pdf/chlorhexidine-in-endodontics-1pqjow6qiz.pdf

Chlorhexidine in Endodontics

Objective. The aim of this in vitro study was to assess the substantive antimicrobial activity of different medicaments in human root dentin. Study Design. Canals of 98 roots were enlarged to standard size and medicated for 7 days with the following: (1) 2% chlorhexidine (CHX) gel, (2) 0.2% CHX gel, (3) 2% CHX solution, (4) Ca(OH) 2 , (5) Ca(OH) 2 + 0.2% CHX gel, (6) 2% CHX solution + a 25% CHX-containing controlled-release device, (7) saline, and (8) gel vehicle. After medication, canals were inoculated with Enterococcus faecalis for 21 days. Dentin samples were collected with Gates-Glidden burs into brain heart infusion broth, and bacterial growth was assessed with spectrophotometric analysis of optical density after 72 hours of incubation. Results. Mean optical densities were significantly lower for groups with 2% CHX (1, 3, and 6) when compared with those of the controls ( P Conclusions. Canal dressing for 1 week with 2% CHX may provide residual antimicrobial activity against E faecalis . (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;94:240-5)

/pdf/substantive-antimicrobial-activity-in-chlorhexidine-treated-nkih16dumy.pdf

Substantive antimicrobial activity in chlorhexidine-treated human root dentin.

Objective We sought to assess the efficacy of chlorhexidine (CHX) and calcium hydroxide, Ca(OH) 2 , against Enterococcus faecalis in vitro. Study design The effect of CHX (0.2% and 2% in gel or solution) and Ca(OH) 2 (alone or with 0.2% CHX gel) was evaluated by using the agar diffusion test and an in vitro human root inoculation method, to measure zone of inhibition or bacterial growth with optical density analysis, respectively. For optical density analysis, samples from infected root canals were collected after 7 days of medication and were cultured for 24 hours in brain-heart infusion to detect viable bacteria. Results In the agar diffusion test, CHX was effective against E faecalis in a concentration-dependent fashion, but Ca(OH) 2 alone had no effect. In the root canal inoculation test, CHX was significantly more effective against E faecalis than Ca(OH) 2 was ( P Conclusions CHX is effective against E faecalis in vitro. Further in vivo studies are needed to confirm the value of CHX in clinical treatment.

J.Miguel Santos

Papers

Substantive antimicrobial activity in chlorhexidine-treated human root dentin.

Efficacy of chlorhexidine- and calcium hydroxide–containing medicaments against Enterococcus faecalis in vitro