Phages in a thermoreversible sustained-release formulation targeting E. faecalis in vitro and in vivo.

INTRODUCTION: Enterococcus faecalis is a key pathogen recovered from root canals when conventional treatment fails. Phage therapy has generated new interest in combating pathogens. A sustained-release formulation using specific phages against E. faecalis may offer an alternative approach. OBJECTIVES: To evaluate the efficacy of anti-E. faecalis phages formulated in a thermo- sustained-release system against E. faecalis in vitro and in vivo. METHODS: EFDG1 and EFLK1 phages were formulated with poloxamer P407. Gelation time, phage survival, activity and toxicity were evaluated. Lytic activity was evaluated in vitro against E. faecalis at various growth phases, including anti-biofilm activity. Methods included viable bacterial count (CFU/mL), biofilm biomass determination and electron microscopy (live/dead staining). Further evaluation included infected incisors in an in vivo rat model. Anti-E. faecalis phage-cocktail suspension and sustained-release phage formulation were evaluated by viable bacterial count (CFU/mL), histology, scanning electron microscopy (SEM) and 16S genome sequencing of the microbiota of the root canal. RESULTS: Gelation time for clinical use was established. Low toxicity and a high phage survival rate were recorded. Sustained-release phages reduced E. faecalis in logarithmic (4 logs), stationary (3 logs) and biofilm (4 logs) growth phases. Prolonged anti-biofilm activity of 88% and 95% reduction in biomass and viable counts, respectively, was recorded. Reduction of intracanal viable bacterial counts was observed (99% of enterococci) also seen in SEM. Phage treatment increased Proteobacteria and decreased Firmicutes. Histology showed reduced periapical inflammation and improved healing following phage treatment. CONCLUSION: Poloxamer P407 formulated with phages has an effective and long-lasting effect in vitro and in vivo targeting E. faecalis.

Critical Review on Eliminating Endodontic Dental Infections Using Herbal Products.

The main purpose of a root canal treatment is to eliminate the bacteria and their products from the pulp space. Chemomechanical preparation (chemical-refers to irrigating solutions, i.e., either synthetic chemicals or herbal solutions and mechanical-refers to instrumentation of a root canals with endodontic files) of a root canal system plays a major role in obtaining the rationale of root canal treatment. Various synthetic chemicals known as endodontic irrigants play a major role in disinfection, but also have undesirable properties like allergic potential, toxicity, unacceptable taste, etc. Today there is a major change in trend towards the use of natural herbal medicines as a part of dental treatment due to its easy availability, less toxicity, and cost effectiveness. This article aims to provide a comprehensive review of various herbal endodontic irrigants evaluated for their effectiveness in the disinfection of a root canal system. This literature review is conducted using electronic databases "PubMed," "Google Scholar," and "Scopus," and articles were limited to those in the English language and published between 1980 and 2014.

A comparative evaluation of antibacterial effectiveness of sodium hypochlorite, Curcuma longa, and Camellia sinensis as irrigating solutions on isolated anaerobic bacteria from infected primary teeth.

CONTEXT: In endodontics, most of the commercial intra-canal medicaments have cytotoxic reactions and because of their inability to eliminate bacteria from dentinal tubules, recent medicine has turned its attention to the usage of biologic medication prepared from natural plants. The literature to testify the efficacy of natural alternatives in primary teeth is meagre and its effects as irrigating solutions need to be evaluated. AIM: To evaluate the antibacterial effectiveness of sodium hypochlorite, ethanolic extracts of Curcuma longa (turmeric) and Camellia sinensis (green tea) as irrigating solutions against the anaerobic bacteria isolated from the root canals of infected primary teeth. MATERIALS AND METHODS: Thirty patients were selected based on the selected inclusion and exclusion criteria. Preoperative radiographs were taken. Rubber dam isolation and working length estimation were done, following which thirty samples were taken from the root canals of infected primary teeth using sterile absorbent paper points and transferred to tubes containing thioglycolate transport medium. The bacteria were then isolated using standard microbiological protocols and were subjected to antibiotic sensitivity testing using the three test irrigants. STATISTICAL ANALYSIS: SPSS 18 software using Chi-square test was used for statistical analysis. RESULTS: The most commonly isolated bacteria included Porphyromonas sp., Bacteroides fragilis, Peptostreptococcus, and Staphylococcus aureus. Sodium hypochlorite and C. longa (turmeric) showed good antibacterial effect and were effective against most of the isolated bacteria. There was statistically significant difference in the antibacterial effect among the three tested groups (P < 0.001). The least effective was C. sinensis (green tea). CONCLUSION: The infected primary teeth almost always present with a polymicrobial structure with a wide variety of anaerobic bacteria. The chemo-mechanical preparation plays an important role in eradicating the population of predominant micro-organisms in treating these teeth with promising effects with the use of newer test irrigants while avoiding the side effects of sodium hypochlorite.

In vitro evaluation of MTAD and nisin in combination against common pathogens associated with root canal infection.

INTRODUCTION: Many pathogenic microorganisms were found in an infected root canal. The object of this study was to evaluate the effect of MTAD in combination with nisin on the pathogens associated with root canal infection. METHODS: The survival rates of 9 pathogenic bacteria were determined after 1-, 5-, and 10-minute treatment with MTAD, MTAN (substitution of doxycycline with nisin), and MTADN (nisin in combination with doxycycline). The survival rates of Enterococcus faecalis in the starvation phase and pretreatment alkalization as well as in the normal physiological state under MTAD, MTAN, and MTADN challenge for 1, 5, and 10 minutes were evaluated and compared. Furthermore, scanning electron microscopy was used to observe the morphologic modification of Actinomyces naeslundii, Lactobacillus paracasei, and Porphyromonas gingivalis after MTAD and MTADN treatment. RESULTS: L. fermenti, L. paracasei, A. viscosus, A. naeslundii, Streptococcus gordonii, and Peptostreptococcus were more sensitive to MTADN and MTAN than to MTAD. MTAD, MTAN, and MTADN showed a rapid antibacterial effect on P. gingivalis, Prevotella intermedia, and Fusobacterium nucleatum. Enterococcus faecalis in the stress state was as sensitive to MTAD, MTAN, and MTADN as the control E. faecalis. Furthermore, in the observation of scanning electron microscopy, the membranes in A. naeslundii and L. paracasei presented significant rupture, and P. gingivalis did not exhibit significant damage after MTADN treatment. CONCLUSIONS: MTAD in combination with nisin improved antibacterial efficacy against pathogens, especially for some gram-positive bacteria associated with persistent intracanal infection. Therefore, the combination had the potential to be used as an effective intracanal irrigation.

Antimicrobial activity of Arctium lappa constituents against microorganisms commonly found in endodontic infections.

This study evaluated in vitro the antimicrobial activity of rough extracts from leaves of Arctium lappa and their phases. The following microorganisms, commonly found in the oral cavity, specifically in endodontic infections, were used: Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Candida albicans. The agar-diffusion method allowed detection of the hexanic phase as an inhibitor of microbial growth. Bioautographic assays identified antimicrobial substances in the extract. The results showed the existence, in the rough hexanic phase and in its fractions, of constituents that have retention factors (Rf) in three distinct zones, thereby suggesting the presence of active constituents with chemical structures of different polarities that exhibited specificity against the target microorganisms. It may be concluded that the Arctium lappa constituents exhibited a great microbial inhibition potential against the tested endodontic pathogens.

Antimicrobial efficacy of chloroxylenol and chlorhexidine in the treatment of infected root canals.

PURPOSE: To investigate the antimicrobial efficacy of a chlorhexidine gluconate (2.0%) and of an ethanolic chloroxylenol solution (10%) as a temporary root canal dressing against selected test microorganisms (Staphylococcus aureus, Streptococcus faecium, Escherichia coli, Candida albicans). MATERIALS AND METHODS: Extracted single-rooted human teeth were instrumented up to size 40. After removal of the smear layer suspensions of the test microorganisms were inserted into the root canals. After incubation for 48 hrs each suspension of the test organisms was removed and the root canals were filled with one of the two different disinfectants. The teeth were then incubated for 48 hrs. Twelve teeth and three controls were used for each of the four test organisms and each of the two regimens. After incubation, each root canal was instrumented and the removed canal wall dentin was examined microbiologically. RESULTS: With a contact time of 48 hrs between the two disinfectants and the four bacterial suspensions the medications led to a total killing of microorganisms in 82% of a total of 96 contaminated teeth. In the dentin layer situated 50 microm from the root canal, both medications achieved bacterial killing in a range from 99.9% to 99.99%, depending on the test organism. There were no significant differences (P> 0.1) between the relative antimicrobial activity of the two root canal dressings.

Evaluation of the effectiveness of sodium hypochlorite used with three irrigation methods in the elimination of Enterococcus faecalis from the root canal, in vitro.

The effectiveness of 4.0% sodium hypochlorite (NaOCl) used with three irrigation methods in the elimination of Enterococcus faecalis from the root canal was tested in vitro. Root canals contaminated with E. faecalis were treated as follows: (i) irrigation with 2 mL of NaOCl solution and agitation with hand files; (ii) irrigation with 2 mL of NaOCl solution and ultrasonic agitation; (iii) irrigation with NaOCl alternated with hydrogen peroxide. Contaminated canals irrigated with sterile saline solution served as the control. Paper points used to sample bacteria from the root canals were transferred to tubes containing 5 mL of brain heart infusion (BHI) broth. Tubes were incubated and the appearance of broth turbidity was indicative of bacteria remaining in the root canal. There were no statistically significant differences between the experimental groups. However, NaOCl applied by the three methods tested, was significantly more effective than the saline solution (control group) in disinfecting the root canal.