Endodontic sealers that possess both optimum flow ability and antimicrobial properties may theoretically assist in the elimination of microorganisms located in confined areas of the root canal system. The antimicrobial effects and the flow rate of the following sealers were investigated and compared: Kerr Pulp Canal Sealer EWT, Grossman's Sealer, ThermaSeal, Sealer 26, AH Plus, and Sealer Plus. The agar diffusion test was used to assess the antimicrobial activity of the sealers. In the flow assay, the sealers were placed between two glass slabs and a weight of 500 g was placed on the top of the glass. The diameters of the formed discs were recorded. All root canal sealers tested showed some antimicrobial activity against most of the microorganisms. There were no significant differences between the materials tested (p > 0.05). All root canal sealers also flowed under the conditions of this study. Statistical analysis of the results revealed that AH Plus and Kerr Pulp Canal Sealer EWT had flow values significantly superior to the other sealers tested (p > 0.05). Taken together, these findings suggest that these sealers have the potential to help in the microbial control in the root canal system.Endodontics is essentially a clinical discipline concerned with the prevention and control of the root canal infection. Cleaned and shaped root canals must be three-dimensionally filled, eliminating the empty space, which has the potential to be infected or reinfected. In addition, by creating a fluid-tight apical, lateral, and coronal seal, root canal fillings may confine residual initants within the root canal system, impeding their egress to the periradicular tissues. A fluid-tight seal of the root canal system also prevents both coronal recontamination by saliva and seeping of periradicular tissue fluids into the root canal, denying a nutrient supply to the remaining microorganisms. Therefore, root canal obturation plays an important role in both the prevention and control of endodontic infections (1).Most root canal filling techniques use core materials associated with endodontic sealers. Core obturating materials, such as guttapercha, usually occupy space, whereas the endodontic sealers enhance the possible attainment of an impervious seal by serving as a filler for canal irregularities and minor discrepancies between the root canal wall and the core material. Several properties are required to an ideal endodontic sealer (2). Among them sealing ability, biocompatibility, and antimicrobial activity probably influence the success of the root canal treatment (1).To create and maintain a three-dimensional seal of the entire root canal system, sealers should have adhesiveness, be dimensionally stable, be insoluble to oral and tissue fluids, and have an adequate flow rate. This latter property allows the material to penetrate into irregularities, isthmi fins and ramifications, which increases the likelihood of obtaining an adequate seal of the root canal system. Moreover, sealers that possess both optimum flow ability and a...

Direct molecular approaches appear to be a valuable tool for the rapid and reliable diagnosis of infectious diseases, as well as for research purposes. There was no correlation between target microbial species and symptoms.

Fusobacterium nucleatum is a Gram-negative, non-spore-forming, nonmotile, obligatory anaerobic rod that is normally isolated from the oral cavity. Epidemiological studies have shown that this species is one of the most prevalent in primary root canal infections. The purpose of this study was to compare the effectiveness of bacteriological culture, 16S rDNA directed polymerase chain reaction and checkerboard DNA-DNA hybridization for detection of F. nucleatum strains in infected teeth associated with periradicular lesions. Thirteen single-root teeth from adult patients, all having carious lesions, necrotic pulps, and radiographic evidence of periradicular bone loss were included in this study. Combining all methods, the results indicated that F. nucleatum was present in approximately 31% (4 of 13) of the specimens. Incidence of F. nucleatum in root canal infections, as evaluated in this study by polymerase chain reaction, culture, and DNA-DNA hybridization, was 15.4%, 15.4%, and 10.0%, respectively. Our data demonstrated that no method used herein could be considered superior for detecting F. nucleatum directly from clinical samples. However, the small number of samples examined and the low prevalence that was observed should be considered.