Molecular Method of Detection of Primary Endodontic Infection- An Ex Vivo Study.

The removal of microorganism and debris from the root canal system is the prerequisite for success of treatment. This can be achieved by thorough cleaning, shaping and disinfection of the root canal system. The aim of the present study is to investigate the presence of microorganism in primary endodontic infection in South Canara population using PCR technique.METHODSFifty patients with primary endodontic infection were selected for the study. Access cavity preparation was done followed by working length determination and first sample was collected by placing the paper point near the root apex for 1 min and immediately the samples were placed in Tris-EDTA buffer solution, stored at -200 C, followed by PCR analysis of the sample using specific primers for detection of microorganisms.RESULTSA total of 50 cases with primary endodontic infection were analysed for the presence of microorganism within the root canal system. Percentage analysis was done, and the positive results were obtained only for Porphyromonas endodontalis in 50 % of cases.CONCLUSIONSPorphyromonas endodontalis was the prevalent organism seen in primary endodontic infection in this particular geographic distribution.

Effects of Porphyromonas endodontalis lipopolysaccharides on the expression of matrix metalloproteinase-9 in mouse osteoblasts / 中华口腔医学杂志

Objective@#To evaluate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (Pe) on the expression of matrix metalloproteinase-9 (MMP-9) mRNA and protein as well as enzyme activity in MC3T3-E1 cells and the role of nuclear factor-κB (NF-κB) in the process, so as to investigate the expression of MMP-9 dependent signaling pathways in mouse osteoblasts induced by Pe LPS.@*Methods@#The experiment was conducted in 3 sessions: MC3T3-E1 cells were treated with various concentrations of Pe LPS (0-20 mg/L) and 10 mg/L Pe LPS for different time intervals (0-48 h). The expression of MMP-9 mRNA and protein were detected by real-time reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), while the enzyme activity was detected by gelatin zymography method. The expression of MMP-9 mRNA was also detected in 10 mg/L Pe LPS treated MC3T3-El cells after pretreated with specific NF-κB inhibitor BAY 11-7082 for l h. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package.@*Results@#The levels of MMP-9 mRNA and protein increased significantly after the treatment with various concentrations of Pe LPS (0-20 mg/L), which indicated that Pe LPS induced osteoblasts to express MMP-9 in dose dependent manners. The expression of MMP-9 protein increased from (5 395±362) ng/L (blank control group) to (12 684±375) ng/L (20 mg/L group). Maximal induction of MMP-9 mRNA expression was found in the MC3T3-E1 cells treated with 10 mg/L Pe LPS for 24 h. The expression of MMP-9 mRNA in the 20 mg/L group was about 7 times than that in the blank control group. After 24 h, the expression of MMP-9 mRNA decreased. Maximal expression of MMP-9 protein was found in the MC3T3-E1 cells treated with 10 mg/L Pe LPS for 48 h ([35 055±2 346] ng/L) showing the highest enzyme activity. The mRNA of MMP-9 decreased significantly after pretreatment with 10 µmol/L BAY 11-7082 for 1 h.@*Conclusions@#Pe LPS might induce the expression of MMP-9 in MC3T3-E1 cells through the signaling of NF-κB.

In vitro effects of Melaleuca alternifolia essential oil on growth and production of volatile sulphur compounds by oral bacteria

ABSTRACT Objective Halitosis can be caused by microorganisms that produce volatile sulphur compounds (VSCs), which colonize the surface of the tongue and subgingival sites. Studies have reported that the use of natural products can reduce the bacterial load and, consequently, the development of halitosis. The aim of this study was to evaluate the antimicrobial activity of the essential oil of Melaleuca alternifolia on the growth and volatile sulphur compound (VSC) production of oral bacteria compared with chlorhexidine. Material and Methods The effects of these substances were evaluated by the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) in planktonic cultures of Porphyromonas gingivalis and Porphyromonas endodontalis. In addition, gas chromatography analyses were performed to measure the concentration of VSCs from bacterial cultures and to characterize M. alternifolia oil components. Results The MIC and MBC values were as follows: M. alternifolia - P. gingivalis (MIC and MBC=0.007%), P. endodontalis (MIC and MBC=0.007%=0.5%); chlorhexidine - P. gingivalis and P. endodontalis (MIC and MBC=1.5 mg/mL). M. alternifolia significantly reduced the growth and production of hydrogen sulfide (H2S) by P. gingivalis (p<0.05, ANOVA-Dunnet) and the H2S and methyl mercaptan (CH3SH) levels of P. endodontalis (p<0.05, ANOVA-Dunnet). Chlorhexidine reduced the growth of both microorganisms without altering the production of VSC in P. endodontalis. For P. gingivalis, the production of H2S and CH3SH decreased (p<0.05, ANOVA-Dunnet). Conclusion M. alternifolia can reduce bacterial growth and VSCs production and could be used as an alternative to chlorhexidine.

Antibacterial activity of Cu ions released from 316L-Cu antibacterial stainless steel / 中国组织工程研究

BACKGROUND:316L-Cu antibacterial stainless steel is made by adding a certain amount of copper into the stainless steel fol owed by a special heat treatment to uniformly disperse copper-rich precipitates in stainless steel substrate, thereby harvesting the antibacterial properties. OBJECTIVE:To evaluate the antibacterial activity of the Cu ions released from 316L type Cu-bearing antibacterial stainless steels against Porphyromonas gingivalis, thereby providing biomedical evidence for its clinical application. METHODS:The medical 316L stainless steel samples at a surface area to volume ratio of 0.1 cm2/L were soaked in simulated body fluids at 37 ℃ for 1-10 days. A graphite furnace atomic absorption spectrophotometer was employed to detect the amount of Cu release in the simulated body fluids each day and then the rate of Cu release per day could be determined. The antibacterial activities of the steel samples were evaluated by a standard film-covered method under a scanning electron microscope. RESULTS AND CONCLUSION:The daily Cu releasing amount from the 316L-Cu stainless steel within 10 days was significantly higher than that of 316L stainless steel, and al the values remained nearly constant. With time, the sterilizing rate of 316L-Cu stainless steel was gradual y increased, and reached 100%until the 10th hour. Porphyromonas gingivalis showed some morphological changes at 3 hours after treated with 316L-Cu stainless steel, appeared with cleavage at 6 hours, and mostly disintegrated into pieces at 9 hours. The results indicated that the 316L-Cu antibacterial stainless steel showed excel ent antibacterial property against Porphyromonas gingivalis, slowly release Cu irons, and alter the surrounding microenvironment, which is a highly promising biomaterial and has good clinical value.

The effects of sonicated extract of Porphyromonas endodontalis on the cell cycle and apoptosis of osteo-blasts / 实用口腔医学杂志

Objective:To observe the effects of sonicated extract of Porphyromonas endodontalis(P.endodontalis)on the cell cy-cle and apoptosis of human osteoblastic hFOB 1 .1 9 cells.Methods:hFOB 1 .1 9 cells were treated with sonicated extract of P.end-odontalis at 0 (the control),1 ,1 0 and 1 00 μg/ml for 1 2,24 and 48 h respectively.MTT assay was used to examine cell prolifera-tion.The cell cycle distribution and apoptosis were examined by flow cytometry.Results:The sonicated exact of P.endodontalis in-hibited the proliferation of hFOB 1 .1 9 cells in a time-and dose-dependent manner.24 h treatment of 1 0 μg/ml and 1 00 μg/ml ex-act arrested the cell cycle of the cells in G1 phase,48 h treatment induced apoptosis in a dose-dependent manner.Conclusion:Sonicated exact of P.endodontalis may arrest hFOB 1 .1 9 cells in G1 phase and induce cell apoptosis,leading to inhibition of the cell proliferation.

Gene expression of human coronary artery endothelial cells in response to Porphyromonas endodontalis invasion / 대한치과보존학회지

During the last two decades, there has been an increasing interest in the impact of oral health on atherosclerosis and subsequent cardiovascular disease (CVD). To date, some periodontal pathogens including Porphyromonas gingivalis (P. gingivalis) have been reported to be relevant to CVD. Porphyromonas endodontalis (P. endodontalis), which shares approximately 87% sequence homology with P. gingivalis, is mostly found within infected root canals. However, recent studies reveal that this pathogen also resides in the dental plaque or periodontal pocket in patients with periodontitis. It has been shown that P. endodontalis invades human coronary artery endothelial cells (HCAEC) and coronary artery smooth muscle cells (CASMC). To evaluate whether P. endodontalis can participate in the progression of atherosclerosis and CVD, we examined the changes in transcriptional gene expression profiles of HCAEC responding to invasion by P. endodontalis in this study. The following results were obtained. 1. Porphyromonas endodontalis was invasive of HCAEC. 2. According to the microarray analysis, there were 625 genes upregulated more than two-folds, while there were 154 genes downregulated by half. 3. Upregulated genes were relevant to inflammatory cytokines, apoptosis, coagulation and immune response. Enhanced expression of MMP-1 was also noticeable. 4. The transcription profiles of the 10 selected genes examined by real-time PCR agreed well with those observed in the microarray analysis. Thus, these results show that P. endodontalis presents the potential to trigger and augment atherosclerosis leading to CVD.

The levels of interleukin-2, interferon-gamma, interleukin-4 and T lymphocyte subpopulations in rat pulpal inflammation induced experimentally by specific bacteria / 대한치과보존학회지

Immune responses associated with bacterial infection involve various inflammatory cells. Clinical symptoms and pathologic features are particularly influenced by the predominant cells. Among inflammatory cells, T cells have the heterogenity. T cells may develop into the mature cells expressing the cell surface markers with different functions and T helper cells are categorized into Th1 and Th2 cells based on their different patterns of cytokine production. The objective of this study was to investigate the change of expression of surface markers on T cells and the Th1/Th2 immune response in pulpal inflammation associated with specific bacteria. We experimentally induced pulpal inflammation in rat incisors by drilling without coolant and innoculated with Streptococcus mutans (S.M. group), Porphyromonas endodontalis (P.E. group), or only sterile cotton (control group). After 1, 2, and 5 days, mandibular incisors were extracted and the pulp tissues were extirpated. The expressions of IL-2 recepters (CD25) and ICAM-1 (CD54) on CD4+ and CD8+ cells in the pulps were determined using a flow cytometer, and the concentration of IL-2, IFN-gamma and IL-4 was measured by enzyme-linked immunosorbent assay. The results were as follows; 1. In the S.M. group, CD4+ cells were more increased at 2nd day than 1st day and in the P.E. group, CD8+ cells were more increased at 2nd day than 1st day. 2. The percentages of CD4+, CD4+25+ and CD4+54+ cells were decreased in the pulp tissues at 5th day after irritation in all groups. 3. The ratios of CD4+/CD8+, CD4+/CD4+25+ and CD4+/CD4+54+ in the pulps at 2nd day after irritation by P. endodontalis were significantly lower than the other groups. 4. The higher concentrations of IFN-gamma than IL-4 in the pulps at 2nd day after irritation by P. endodontalis showed that T helper 1 reaction were predominant in the early stage of the pulpal inflammation induced by P. endodontalis. 5. The higher concentrations of IL-4 than IFN-gamma in the pulps at 1st day and 5th day after irritation by S. mutans were measured but the differences were not significant.

IL-1 and TNF-alpha release in human polymorphonuclear leukocytes after exposure to calcium hydroxide treated Porphyromonas endodontalis lipopolysaccharide / 대한치과보존학회지

Bacterial lipopolysaccharide (LPS) plays a major role in stimulating the synthesis and release of the principal osteoclast-activating cytokines, namely, interleukin 1 and tumor necrosis factor-alpha from immune cells. Although monocytes/macrophages are the main producers of these cytokines, recent evidence has indicated that polymorphonuclear leukocytes (PMN) have the ability to release IL-1 and TNF-alpha. Calcium hydroxide has been shown to be an effective medicament in root canal infections, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)2 may also be the result of direct inactivation of LPS. The purpose of this study was to investigate whether treatment of Porphyromonas endodontalis LPS with calcium hydroxide alters its biological action as measured by human PMN secretion of IL-1 and TNF-alpha, and it was compared with Escherichia coli LPS. P. endodontalis ATCC 35406 was cultured in anaerobic condition, and LPS was extracted using the hot-phenol water extraction method and purified. Purchased E. coli LPS was also purified. 100 microg/ml of each LPS in pyrogen free water were incubated with 25mg/ml Ca(OH)2 at 37degrees C for 7 days. The supernatants were subjected to ultrafiltration, and the isolates were lyophilized and weighed. PMNs were obtained from peripheral blood by centrifugation layered over Lymphoprep. The cells were resuspended (4x106 cells/ml) in RPMI 1640 followed by treatment with various concentrations of LPS (0, 0.1, 1, 10microg/ml) for 24 hours at 37degrees C in 5% CO2 incubator. The supernatants of cells were collected and the levels of IL-1alpha, IL-1beta and TNF-alpha were measured by enzyme-linked immunosorbent assay. The results were as follows; 1. The levels of IL-1alpha, IL-1beta, TNF-alpha from PMN treated with each LPS were significantly higher than those released from unstimulated PMN of the control group (p0.05). 3. The levels of secretion for all three cytokines were affected in a dose-dependent manner in PMN stimulated with each LPS (p0.05). 4. The levels of all three cytokines released from PMN stimulated with P. endodontalis LPS were significantly lower than those released from PMN stimulated with E. coli LPS (p<0.05).

Detection of porphyromonas endodontalis in chronic periapical periodontitis by PCR / 实用口腔医学杂志

Objective:To evaluate the prevalence of Pe in clinical samples of chronic periapical periodontitis.Methods:A total of 100 clinical samples of chronic periapical periodontitis were collected and Pe 16S rDNA was detected by using 16S rDNA gene-directed PCR.The detection rate of Pe were calculated.Results:The detection rate of Pe was 50% in the 100 clinical samples.Conclusion:The results indicate that Pe is closely associated with endodontic infections.