Removal of bacterial biofilm from the root canal system is essential for the management of endodontic disease. Here we evaluated the antibacterial effect of N-acetylcysteine (NAC), a potent antioxidant and mucolytic agent, against mature multispecies endodontic biofilms consisting of Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans and Enterococcus faecalis on sterile human dentin blocks. The biofilms were exposed to NAC (25, 50 and 100 mg/mL), saturated calcium hydroxide or 2% chlorhexidine solution for 7 days, then examined by scanning electron microscopy. The biofilm viability was measured by viable cell counts and ATP-bioluminescence assay. NAC showed greater efficacy in biofilm cell removal and killing than the other root canal medicaments. Furthermore, 100 mg/mL NAC disrupted the mature multispecies endodontic biofilms completely. These results demonstrate the potential use of NAC in root canal treatment.
Strains of Porphyromonas gingivalis, a periodontopathic bacterium, are classified into six genotypic variants based on nucleotide sequence differences in the fimA gene encoding FimA. A PCR assay using primer sets specific for each genotype has demonstrated that the most predominant fimA genotype in periodontitis patients is type II, which is now commonly referred to as the periodontitis-associated fimA genotype of P. gingivalis. However, the potential for false type II fimA positives caused by cross-hybridization of type II fimA-specific primers with type Ib fimA has complicated the genotyping. A previous study developed new primers that specifically amplified only the DNA fragment of type II fimA. The aim of the present study was to assess the prevalence of P. gingivalis fimA genotypes in Korean adults and to reconfirm the relationship between type II fimA and periodontitis using the new primers. Among 412 Korean adults, P. gingivalis was detected in 97.5 % of patients and 57.8 % of healthy subjects. Type II fimA was the most widely distributed type among healthy and periodontitis subjects. Organisms with types II, Ib and IV fimA had a significant frequency of occurrence in periodontitis subjects. Statistical analysis, however, revealed that a more significant correlation was found between periodontitis and the occurrence of type Ib fimA. INTRODUCTIONPorphyromonas gingivalis is a Gram-negative, black-pigmented anaerobe associated with periodontal diseases (Amano et al., 1999). P. gingivalis fimbriae are filamentous components located on the cell surface and are critical for the promotion of bacterial infection (Nakagawa et al., 2002;Amano, 2003). The fimA gene encoding FimA, a subunit of the fimbriae, has been classified into six genotypes (I-V and Ib) based on their nucleotide sequences (Nakagawa et al., 2002). A PCR assay using primer sets specific for each genotype has been used to determine fimA types in subjects with various periodontal and systemic conditions (Amano et al., 1999;Nakagawa et al., 2000Nakagawa et al., , 2002Beikler et al., 2003;Missailidis et al., 2004;Miura et al., 2005;Davila-Perez et al., 2007). Several reports have shown that there is a significant prevalence of P. gingivalis harbouring genotypes II, Ib and IV fimA in periodontitis patients (Amano et al., 1999Nakagawa et al., 2002;Missailidis et al., 2004; Nakano et al., 2004;Miura et al., 2005). However, the nucleotide sequence of type Ib fimA shares 77.5 % identity with that of type II fimA (Nakagawa et al., 2002) and the potential for false type II fimA positives caused by cross-hybridization of type II fimA-specific primers with type Ib fimA has complicated the genotyping (Nakagawa et al., 2002;Enersen et al., 2008). Recently, a new primer set, designated type II (new), was designed, and the specificity of the new primers was examined using 14 P. gingivalis strains that possessed each of the six fimA genotypes and other bacterial species (Moon et al., 2011 METHODSClinical specimens and bacterial DNA isolation. The study comprised 4...
Prevotella intermedia, a major periodontopathogen, has been shown to be resistant to many antibiotics. In the present study, we examined the effect of the FDA-approved iron chelators deferoxamine (DFO) and deferasirox (DFRA) against planktonic and biofilm cells of P. intermedia in order to evaluate the possibility of using these iron chelators as alternative control agents against P. intermedia. DFRA showed strong antimicrobial activity (MIC and MBC values of 0.16 mg ml "1 ) against planktonic P. intermedia. At subMICs, DFRA partially inhibited the bacterial growth and considerably prolonged the bacterial doubling time. DFO was unable to completely inhibit the bacterial growth in the concentration range tested and was not bactericidal. Crystal violet binding assay for the assessment of biofilm formation by P. intermedia showed that DFRA significantly decreased the biofilm-forming activity as well as the biofilm formation, while DFO was less effective. DFRA was chosen for further study. In the ATP-bioluminescent assay, which reflects viable cell counts, subMICs of DFRA significantly decreased the bioactivity of biofilms in a concentration-dependent manner. Under the scanning electron microscope, P. intermedia cells in DFRA-treated biofilm were significantly elongated compared to those in untreated biofilm. Further experiments are necessary to show that iron chelators may be used as a therapeutic agent for periodontal disease.
The objective of this study was to investigate the changes of skin temperatures over the temporomandibular joint (TMJ) and clinical findings consecutively during conservative treatments in unilateral TMJ arthralgia patients. The study enrolled 31 patients with unilateral TMJ arthralgia and 26 healthy control subjects based on the Research Diagnostic Criteria for Temporomandibuar Disorders. The measurements of skin temperatures over the TMJ and clinical examinations were performed in all subjects at baseline, 2 and 4 weeks later, and patients were given conservative treatments. Thermographic examinations were performed before and after chewing activity for 5 minutes in each session. The data were analyzed by repeated-measures ANOVA. In affected TMJ, the change in temperature between before and after chewing activity was significantly high in TMJ arthralgia group and decreased after 2 and 4 weeks. Thermal asymmetry measured before chewing activity showed insignificant difference between groups. However, those measured after chewing activity were significantly high in TMJ arthralgia group and reduced to the similar level of control group after 2 and 4 weeks. After chewing activity, both skin temperature over painful TMJ and the extent of thermal asymmetry in TMJ arthralgia patients were higher than those of control group. These thermal indices of TMJ arthralgia patients were reduced in accordance with clinical improvements by conservative treatments. Consecutive thermography accompanying chewing activity which may increase TMJ pain temporarily can be a useful adjunctive technique to diagnose TMJ arthralgia and evaluate its clinical progression including level of pain.
To the Editor; In the above article, we found that our affiliation was published incorrectly.
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