In Vitro Bioactivity and Antibacterial Activity of Strontium-, Magnesium-, and Zinc-Multidoped Hydroxyapatite Porous Coatings Applied via Atmospheric Plasma Spraying.

The beneficial effects of Sr- and Mg-doped hydroxyapatite (HAp) on osteoblast proliferation and bone regeneration have been investigated in the past, and the antibacterial ability of Zn ions is well known. However, HAp coatings doped with these three elements via thermal spraying have not yet been investigated. In this study, HAp powder was synthesized at different pH values (4, 6, 8, and 10) and calcined at different temperatures (200, 400, 600, 800, and 1000 °C) to obtain HAp with the highest purity. Subsequently, strontium-, magnesium-, and zinc-doped HAp powders were synthesized at the optimal pH value and calcination temperature. The HAp powder was then coated onto Ti disks using atmospheric plasma spraying (APS) or vapor-induced pore-forming atmospheric plasma spraying (VIPF-APS) techniques at different working currents (350, 400, and 450 A) and spraying distances (10 and 15 cm). X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy equipped with energy-dispersive spectroscopy were used for material characterization to determine the optimal parameters. With these optimal coating parameters, HAp, Zn-HAp, SrMg-HAp, and ZnSrMg-HAp powders were deposited onto the Ti disks using VIPF-APS and named HAp-Ti, Zn-HAp-Ti, SrMg-HAp-Ti, and ZnSrMg-HAp-Ti, respectively. The in vitro bioactivity of these four groups was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and alkaline phosphatase (ALPase) activity assay. Besides, the antibacterial activities against Prevotella nigrescens, Porphyromonas gingivalis, and Fusobacterium nucleatum were assessed. The results showed that the purity of HAp synthesized at pH 10 and 800 °C was 98.40%. A porous coating without cracks was obtained at a 10 cm spraying distance and 400 A working current using VIPF-APS. SrMg-HAp-Ti and ZnSrMg-HAp-Ti resulted in higher osteoblast proliferation and ALPase activity than the control. Moreover, both Zn-HAp-Ti and ZnSrMg-HAp-Ti exhibited antibacterial activity against the three bacteria. Therefore, ZnSrMg-HAp has potential as a coating for biomedical materials due to its ability to reduce bacterial infection and enhance osseointegration.

Essential Oil from Psidium cattleianum Sabine (Myrtaceae) Fresh Leaves: Chemical Characterization and in vitro Antibacterial Activity Against Endodontic Pathogens

Abstract Endodontic infections result from oral pathogenic bacteria which reach and infect dental pulp, as well as surrounding tissues, through cracks, unrepaired caries and failed caries restorations. This study aims to determine the chemical composition of essential oil from Psidium cattleianum leaves (PC-EO) and to assess its antibacterial activity against endodontic bacteria. Antibacterial activity of PC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method on 96-well microplates. Bacteria Porphyromonas gingivalis (MIC = 20 µg/mL), Prevotella nigrescens (MIC = 62.5 µg/mL), Fusobacterium nucleatum (MIC = 12.5 µg/mL), Actinomyces naeslundii (MIC = 50 µg/mL), Bacteroides fragilis (MIC = 12.5 µg/mL), Aggregatibacter actinomycetemcomitans (MIC = 6.25 µg/mL) and Peptostreptococcus anaerobius (MIC = 62.5 µg/mL) were evaluated and compared to chlorhexidine dihydrochloride (CDH), the positive control. PC-EO was obtained by hydrodistillation with the use of a Clevenger-type apparatus whereas its chemical composition was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Viridiflorol (17.9%), β-caryophyllene (11.8%), 1,8-cineole (10.8%) and β-selinene (8.6%) were the major constituents found in PC-EO, which exhibited high antibacterial activity against all endodontic pathogens under investigation. Therefore, PC-EO, a promising source of bioactive compounds, may provide therapeutic solutions for the field of endodontics.

Multiple aPDT sessions on periodontitis in rats treated with chemotherapy: histomorphometrical, immunohistochemical, immunological and microbiological analyses.

BACKGROUND: The aim of this study was to evaluate the effect of multiple sessions of antimicrobial photodynamic therapy (aPDT) on the treatment of experimental periodontitis (EP) in rats treated with chemotherapy. METHODS: Chemotherapy using 5-fluorouracil (5-FU) consisted of intraperitoneal administration of 60 and 40 mg/kg of 5-FU. 120 rats were subjected to chemotherapy with 5-FU and divided into groups: PT (periodontal treatment); PT+1aPDT (PT and single aPDT session); PT+4aPDT(PT and 4 sessions of aPDT); 1aPDT (single aPDT session); 4aPDT(4 sessions of aPDT). EP was induced in the mandibular molars via ligature placement. The alveolar bone loss (ABL) area in the furcation region was analysed histometrically. Proliferating cell nuclear antigen (PCNA), tartrate-resistant acid phosphatase (TRAP), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG) and cleaved caspase-3 (CC3) were analysed by immunohistochemistry. Prostaglandin E2 was quantified using an ELISA, tumor necrosis factor (TNF)-α and interleukin (IL)-6 were assessed using a multiplex method. The prevalence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella nigrescens, Prevotella intermedia and Fusobacterium nucleatum was assessed using PCR. The data were statistically analysed (P < 0.05). RESULTS: The PT+4aPDT group showed lower ABL than the PT or 1aPDT groups on day 7. Rats treated with aPDT showed a higher number of PCNA-positive cells with reduced immunolabeling of RANKL. Significant reductions in Prevotella nigrescens were observed in the PT+4aPDT group and in Aggregatibacter actinomycetemcomitans for the 1aPDT and 4aPDT groups. CONCLUSION: Repeated sessions of aPDT as an adjunct or alternative therapy were effective at reducing ABL, regulating bone metabolism, and reducing Prevotella nigrescens and Aggregatibacter actinomycetemcomitans.

Antimicrobial Effects of Mastic Extract Against Oral and Periodontal Pathogens.

BACKGROUND: Various antimicrobial agents are widely used in the therapy of oral inflammatory diseases. However, their side effects and the appearance of drug resistance justify research on natural antimicrobial agents to target oral pathogens that are safe for the host. In the present study, antimicrobial properties of mastic extract on commensal and pathogenic oral bacteria, as well as its possible cytotoxic effect toward cells of epithelial and mesenchymal origin, were evaluated and compared with the common antimicrobial agents hydrogen peroxide (H2O2) and chlorhexidine digluconate (CHX). METHODS: Oral and periodontal pathogens (Porphyromonas gingivalis, Streptococcus mutans [Sm], Streptococcus oralis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, and Prevotella nigrescens) were treated with different concentrations of mastic extract, 3% H2O2, and 0.2% CHX, and evaluated with an agar diffusion test. The cytotoxic effect of mastic extract was tested on four cell lines of epithelial and mesenchymal origin (HaCaT, SaOS-2, MC3T3-E1, periodontal ligament [PDL] cells) by neutral red and 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. RESULTS: Mastic extract led to significantly (P ≤0.016) increased inhibition of the tested periodontal pathogens compared with H2O2. No effect of mastic extract was observed on Sm. Mastic extract showed beneficial effects on cell viability because viability values of tested cells were significantly (P ≤0.016) lower for cells treated with CHX and H2O2 compared with mastic extract-treated cells after stimulation for 2, 4, and 6 hours. CONCLUSION: The present data demonstrate mastic extract's inhibition of periodontal pathogens, as well as beneficial effects on cell viability, compared with H2О2, suggesting that it could be considered an alternative antibacterial agent in the prevention of periodontal disease.

Copaifera reticulata oleoresin: Chemical characterization and antibacterial properties against oral pathogens.

Oral infections such as periodontitis and tooth decay are the most common diseases of humankind. Oleoresins from different copaifera species display antimicrobial and anti-inflammatory activities. Copaifera reticulata is the commonest tree of this genus and grows abundantly in several Brazilian states, such as Pará, Amazonas, and Ceará. The present study has evaluated the chemical composition and antimicrobial potential of the Copaifera reticulata oleoresin (CRO) against the causative agents of tooth decay and periodontitis and has assessed the CRO cytotoxic potential. Cutting edge analytical techniques (GC-MS and LC-MS) aided the chemical characterization of CRO. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), determination of the Minimum Bactericidal Concentration (MBC), determination of the Minimum Inhibitory Concentration of Biofilm (MICB50), Time Kill Assay, and Checkerboard Dilution. Conduction of XTT assays on human lung fibroblasts (GM07492-A cells) helped to examine the CRO cytotoxic potential. Chromatographic analyses revealed that the major constituents of CRO were ß-bisabolene, trans-α-bergamotene, ß-selinene, α-selinene, and the terpene acids ent-agathic-15-methyl ester, ent-copalic acid, and ent-polyalthic acid. MIC and MBC results ranged from 6.25 to 200 µg/mL against the tested bacteria. The time-kill assay conducted with CRO at concentrations between 50 and 100 µg/mL showed bactericidal activity against Fusobacterium nucleatum (ATCC 25586) and Streptococcus mitis (ATCC 49456) after 4 h, Prevotella nigrescens (ATCC 33563) after 6 h, Porphyromonas gingivalis (ATCC 33277) and Lactobacillus casei (clinical isolate) after 12 h, and Streptococcus salivarius (ATCC 25975) and Streptococcus mutans (ATCC 25175) after 18 h. The fractional inhibitory concentration indexes (FICIs) revealed antagonistic interaction for Lactobacillus casei (clinical isolate), indifferent effect for Porphyromonas gingivalis (ATCC 33277), Fusobacterium nucleatum (ATCC 25586), Prevotella nigrescens (ATCC 33563), and Streptococcus salivarius (ATCC 25975), and additive effect for Streptococcus mutans (ATCC 25175) and Streptococcus mitis (ATCC 49456). Treatment of GM07492-A cells with CRO demonstrated that concentrations up to 39 µg/mL significantly reduced cell viability as compared to the negative control, being IC50 equal to 51.85 ± 5.4 µg/mL. These results indicated that CRO plays an important part in the search for novel sources of agents that can act against oral pathogens.

Antibacterial activity of commercially available plant-derived essential oils against oral pathogenic bacteria.

This work investigated the antibacterial activity of 15 commercially available plant-derived essential oils (EOs) against a panel of oral pathogens. The broth microdilution method afforded the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the assayed EOs. The EO obtained from Cinnamomum zeylanicum (Lauraceae) (CZ-EO) displayed moderate activity against Fusobacterium nucleatum (MIC and MBC = 125 µg/mL), Actinomyces naeslundii (MIC and MBC = 125 µg/mL), Prevotella nigrescens (MIC and MBC = 125 µg/mL) and Streptococcus mutans (MIC = 200 µg/mL; MBC = 400 µg/mL). (Z)-isosafrole (85.3%) was the main chemical component of this oil. We did not detect cinnamaldehyde, previously described as the major constituent of CZ-EO, in specimens collected in other countries.

Detection and genetic characterization of ß-lactamases in Prevotella intermedia and Prevotella nigrescens isolated from oral cavity infections and peritonsillar abscesses.

A prospective analysis on ß-lactam resistance mechanisms and ß-lactamase prevalence was conducted on Prevotella intermedia and Prevotella nigrescens recovered from patients with chronic periodontitis and peritonsillar abscesses. Both phenotypic and genotypic methods were performed to characterize the ß-lactamases, their coding genes and their genetic contexts. Overall, ß-lactamase production was observed in 64% (16/25) P. intermedia and 23.8% (5/21) P. nigrescens (p < 0.01). Besides higher ß-lactamase production rates were observed in P. intermedia (8/16) than in P. nigrescens (2/16) recovered from chronic periodontitis, almost all isolates from peritonsillar abscesses were producers (8/9 and 3/3, respectively). cfxA, but not cepA and cblA, was detected in those isolates, which were previously categorized as ß-lactamase producers. CfxA producing isolates displayed higher ß-lactam MICs than non-producers in both species. The most frequent allele was cfxA2, followed by cfxA3 and a new allelic variant named cfxA6. The analysis of the downstream flanking region in the three cfxA variants revealed the association with mobA of Tn4555, suggesting their localization in a mobilizable element. ß-lactam resistance and cfxA carriage prevalence seems to be not only related to the bacterial species but also to the infection site.

Combinatorial effects of amoxicillin and metronidazole on selected periodontal bacteria and whole plaque samples.

OBJECTIVE: The aim of the present study was to analyze in vitro the combinatorial effects of the antibiotic combination of amoxicillin plus metronidazole on subgingival bacterial isolates. DESIGN: Aggregatibacter (Actinobacillus) actinomycetemcomitans, Prevotella intermedia/nigrescens, Fusobacterium nucleatum and Eikenella corrodens from our strain collection and subgingival bacteria isolated from patients with periodontitis were tested for their susceptibility to amoxicillin and metronidazole using the Etest. The fractional inhibitory concentration index (FICI), which is commonly used to describe drug interactions, was calculated. RESULTS: Synergy, i.e. FICI values ≤ 0.5, between amoxicillin and metronidazole was shown for two A. actinomycetemcomitans (FICI: 0.3), two F. nucleatum (FICI: 0.3 and 0.5, respectively) and one E. corrodens (FICI: 0.4) isolates. Indifference, i.e. FIC indices of >0.5 but ≤4, occurred for other isolates and the 14 P. intermedia/nigrescens strains tested. Microorganisms resistant to either amoxicillin or metronidazole were detected in all samples by Etest. CONCLUSION: Combinatorial effects occur between amoxicillin and metronidazole on some strains of A. actinomycetemcomitans, F. nucleatum and E. corrodens. Synergy was shown for a few strains only.

Antibiotic resistance in human chronic periodontitis microbiota.

BACKGROUND: Patients with chronic periodontitis (CP) may yield multiple species of putative periodontal bacterial pathogens that vary in their antibiotic drug susceptibility. This study determines the occurrence of in vitro antibiotic resistance among selected subgingival periodontal pathogens in patients with CP. METHODS: Subgingival biofilm specimens from inflamed deep periodontal pockets were removed before treatment from 400 adults with CP in the United States. The samples were cultured, and selected periodontal pathogens were tested in vitro for susceptibility to amoxicillin at 8 mg/L, clindamycin at 4 mg/L, doxycycline at 4 mg/L, and metronidazole at 16 mg/L, with a post hoc combination of data for amoxicillin and metronidazole. Gram-negative enteric rods/pseudomonads were subjected to ciprofloxacin disk-diffusion testing. RESULTS: Overall, 74.2% of the patients with CP revealed subgingival periodontal pathogens resistant to at least one of the test antibiotics. One or more test species, most often Prevotella intermedia/nigrescens, Streptococcus constellatus, or Aggregatibacter actinomycetemcomitans, were resistant in vitro to doxycycline, amoxicillin, metronidazole, or clindamycin, in 55%, 43.3%, 30.3%, and 26.5% of the patients with CP, respectively. Fifteen percent of patients harbored subgingival periodontal pathogens resistant to both amoxicillin and metronidazole, which were mostly either S. constellatus (45 individuals) or ciprofloxacin-susceptible strains of Gram-negative enteric rods/pseudomonads (nine individuals). CONCLUSIONS: Patients with CP in the United States frequently yielded subgingival periodontal pathogens resistant in vitro to therapeutic concentrations of antibiotics commonly used in clinical periodontal practice. The wide variability found in periodontal pathogen antibiotic-resistance patterns should concern clinicians empirically selecting antibiotic treatment regimens for patients with CP.

Efficacy of a new mouth rinse formulation based on 0.07% cetylpyridinium chloride in the control of plaque and gingivitis: a 6-month randomized clinical trial.

AIM: To assess the efficacy of a 0.07% cetylpyridinium chloride (CPC) mouth rinse in the control of plaque and gingival inflammation during a 6-month period. MATERIAL AND METHODS: Adult subjects with moderate gingivitis were selected [≥40% bleeding on marginal probing (BOMP)]. After retrieving microbiological samples and evaluating the clinical parameters (plaque, BOMP and stain indexes), a professional prophylaxis was performed and subjects were randomly assigned to the test (CPC mouth rinse) or to the placebo group. Subjects were re-assessed after 3 and 6 months. RESULTS: A total of 67 patients (35 test, 32 placebo) were included in the analysis. At 6 months, intra-group significant plaque reductions were observed in the test group (0.691, p < 0.001), but not in the placebo (0.181, p = 0.653). At 6 months, the mean BOMP values were lower in the test group (p = 0.052). Changes between baseline and 6 months were significantly higher in the test group both for plaque (p = 0.002) and BOMP (p = 0.037) when compared with the placebo. A microbiological impact was observed in the test group, especially for Prevotella intermedia. CONCLUSION: The evaluated 0.07% CPC-based mouth rinse, used three times per day adjunctively to mechanical tooth cleaning, prevents plaque accumulation and gingival inflammation, as compared to the placebo, for at least 6 months.

Prevalence of ß-lactamase-producing bacteria in human periodontitis.

BACKGROUND AND OBJECTIVE: Beta-lactam antibiotics prescribed in periodontal therapy are vulnerable to degradation by bacterial ß-lactamases. This study evaluated the occurrence of ß-lactamase-positive subgingival bacteria in chronic periodontitis subjects of USA origin, and assessed their in vitro resistance to metronidazole at a breakpoint concentration of 4 µg/mL. MATERIAL AND METHODS: Subgingival plaque specimens from deep periodontal pockets with bleeding on probing were removed from 564 adults with severe chronic periodontitis before treatment. The samples were transported in VMGA III and then plated onto: (i) nonselective enriched Brucella blood agar (EBBA) and incubated anaerobically for 7 d; and (ii) selective trypticase soy-bacitracin-vancomycin (TSBV) and incubated for 3 d in air + 5% CO2 . At the end of the incubation periods, the bacterial test species were identified and quantified. Specimen dilutions were also plated onto EBBA plates supplemented with 2 µg/mL of amoxicillin, a combination of 2 µg/mL of amoxicillin plus 2 µg/mL of the ß-lactamase inhibitor clavulanic acid, or 4 µg/mL of metronidazole, followed by anaerobic incubation for 7 d. Bacterial test species presumptively positive for ß-lactamase production were identified by growth on EBBA primary isolation plates supplemented with amoxicillin alone and no growth on EBBA primary isolation plates containing both amoxicillin plus clavulanic acid. A subset of such isolates was subjected to nitrocefin-based chromogenic disk testing to confirm the presence of ß-lactamase activity. In vitro resistance to 4 µg/mL of metronidazole was noted when growth of test species occurred on metronidazole-supplemented EBBA culture plates. RESULTS: Two-hundred and ninety-four (52.1%) of the study subjects yielded ß-lactamase-producing subgingival bacterial test species, with Prevotella intermedia/nigrescens, Fusobacterium nucleatum and other Prevotella species most frequently identified as ß-lactamase-producing organisms. Of the ß-lactamase-producing bacterial test species strains recovered, 98.9% were susceptible in vitro to metronidazole at 4 µg/mL. CONCLUSION: The occurrence of ß-lactamase-positive subgingival bacterial species in more than half of the subjects with severe chronic periodontitis raises questions about the therapeutic potential of single-drug regimens with ß-lactam antibiotics in periodontal therapy. The in vitro effectiveness of metronidazole against nearly all recovered ß-lactamase-producing subgingival bacterial species further supports clinical periodontitis treatment strategies involving the combination of systemic amoxicillin plus metronidazole.

16S Ribosomal RNA Identification of Prevotella nigrescens from a Case of Cellulitis

No abstract available.

An in vitro comparative study determining bactericidal activity of stabilized chlorine dioxide and other oral rinses.

OBJECTIVE: The study was conducted to determine the bactericidal activity of a stabilized chlorine dioxide oral rinse (CloSYS Oral Rinse) compared to products currently available on the market. METHODS: Oral bacteria associated with gingivitis and periodontitis were exposed to rinses for one minute and five minutes. The numbers of colony forming units per milliliter (CFU/ml) were measured prior to and following exposure to determine the bactericidal activity. RESULTS: As expected, Listerine and Crest Pro-Health demonstrated complete kill on all bacteria exposed within one minute. Breath Rx exhibited the weakest levels of bactericidal effects overall. CloSYS and chlorhexidine rinses proved identical 100% kills against the periodontal pathogens at five minutes; in some cases, CloSYS oral rinse achieved a higher kill at the one-minute mark over the chlorhexidine rinse. CONCLUSION: The results demonstrated that CloSYS Oral Rinse has potential for providing a therapeutic benefit, making it an attractive option to induce compliance in patients concerned about taste and tooth discoloration during oral health therapy.

Bactericidal activity of stabilized chlorine dioxide as an endodontic irrigant in a polymicrobial biofilm tooth model system.

INTRODUCTION: The purpose of this study was to determine bactericidal efficacy of 0.04% stabilized chlorine dioxide, 3% sodium hypochlorite, 2% chlorhexidine gluconate, and sterile distilled water in a polymicrobial biofilm model. METHODS: Roots of 35 permanent bovine incisors had pulps extirpated, and their apical size and root length were standardized. Teeth were coated with mucin, inoculated with standardized suspensions of Streptococcus sanguinis, Actinomyces viscosus, Fusobacterium nucleatum, Peptostreptococcus micros, and Prevotella nigrescens and incubated anaerobically. Teeth were randomly divided into four groups and rinsed for 3 minutes with 15 mL of irrigant. Biofilms were harvested and spiral-plated on selective media. Numbers of bacteria in the harvested biofilms was determined via the standard spiral-plating methodology. Treatment groups were evaluated using the nonparametric Kruskal-Wallis procedure. Pair-wise comparisons among the four groups and five organisms were made using the Wilcoxon-Mann-Whitney procedure. Adjustments for multiple comparisons were made using the Holm method with p < 0.05. RESULTS: Results provide strong evidence of a significant difference in levels of bactericidal activity associated with the type of irrigant for all five bacterial species tested. Levels of bactericidal activity were significantly higher for the NaOCl group than for the stabilized chlorine dioxide (ClO2) group for S. sanguinis, A. viscosus, and P. nigrescens. Results for F. nucleatum and P. micros were not significant after the adjustment for multiple comparisons. CONCLUSIONS: The triple-inoculation bovine tooth model system is a robust, consistent, and reproducible model system to study polymicrobial biofilms. It should be used with the knowledge expansion of biofilm structure and function as well as the development of antimicrobial protocols.

Antibacterial effects of MDPB against anaerobes associated with endodontic infections.

AIM: To investigate the antibacterial effects of 12-methacryloyloxydodecylpyridinium bromide (MDPB), an antibacterial monomer synthesized by combining quaternary ammonium with a methacryloyl group, against three anaerobes associated with endodontic infections using planktonic and biofilm cells. METHODOLOGY: The antibacterial activity of unpolymerized MDPB against Enterococcus faecalis, Fusobacterium nucleatum and Prevotella nigrescens was examined by agar-disc diffusion tests and determination of the minimum inhibitory/bactericidal concentrations (MIC/MBC). Rapid killing effects of MDPB against three bacteria in planktonic form were examined by a cell number counting method, and those against biofilm cells were assessed by a viability staining method. RESULTS: MDPB demonstrated inhibition against all of the bacteria tested by agar-disc diffusion tests. The MIC/MBC values of MDPB for the three anaerobes were much smaller than those of other resin monomers, although greater compared with those of cetylpyridinium chloride or chlorhexidine diacetate for E. faecalis and F. nucleatum. Significant reduction in viable planktonic cells was obtained by contact with 250 microg mL(-1) of MDPB for 20 s (P < 0.05, Fisher's PLSD tests), and 40 s contact with 500 microg mL(-1) or 20 s contact with 1000 microg mL(-1) of MDPB resulted in more than 90% killing. Biofilm cells of all species were completely killed by application of 1000 microg mL(-1) of MDPB for 60 s. CONCLUSION: MDPB was found to have strong antibacterial effects against E. faecalis, F. nucleatum and P. nigrescens, and such effects were rapidly exhibited even against biofilm cells, suggesting the usefulness of application of MDPB to resin-based materials for root canal filling.

Efficacy of amoxicillin and metronidazole combination for the management of generalized aggressive periodontitis.

BACKGROUND: The aim of this study is to evaluate the effects of metronidazole-amoxicillin combination on clinical and microbiologic parameters in patients with generalized aggressive periodontitis. METHODS: Twenty-eight patients were randomly included. The test group (n = 12) received amoxicillin-metronidazole combination and scaling and root planing; the control group (n = 16) received scaling and root planing alone. In addition to the clinical examinations, subgingival plaque samples were analyzed for total cultivable bacteria and the presence of Porphyromonas gingivalis, Tannerella forsythia (previously T. forsythensis), Treponema denticola, Prevotella intermedia, Prevotella nigrescens, Prevotella pallens, and Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) using polymerase chain reaction. RESULTS: All clinical parameters improved significantly compared to baseline (P <0.05) in both groups. There was a statistically significant reduction of pockets and clinical attachment gain in the combined group compared to the control group (P <0.05). Total counts of bacteria also decreased significantly at 3 and 6 months in both groups (P <0.05). T. denticola and T. forsythia were the most prevalent bacteria throughout the study. T. denticola showed a continuous decrease over 6 months in the test group, whereas no change was seen in the control group beyond 3 months. P. gingivalis decreased significantly at 3 months (P <0.05), whereas T. forsythia was the only pathogen decreased below detection limits by the combination therapy with a significant difference compared to the control group (P <0.05). CONCLUSIONS: The results from this study suggest that combined amoxicillin and metronidazole use as an adjunct to scaling and root planing leads to better clinical healing compared to mechanical treatment alone. The polypharmaceutical approach used results in a significant and substantial decrease in T. forsythia and prevents its recolonization for 6 months, suggesting that T. forsythia may determine the long-term stability of periodontal treatment outcomes.

An agar diffusion comparison of the antimicrobial effect of calcium hydroxide at five different concentrations with three different vehicles.

The purpose of this study was to determine if varying the percent (by weight) of aqueous calcium hydroxide or using different vehicles had an effect on its antibacterial efficacy against common endodontic pathogens in a pour plate/traditional streak agar diffusion model. Mixtures of calcium hydroxide powder and sterile saline in 40, 50 and 60 percent concentrations and the commercial preparations UltraCal XS and Vitapex were tested against six known endodontic pathogens with an agar diffusion method. Each medicament was placed in one of five wells, in each of 10 agar plates (n = 10), for cultures of each bacterial species. Zones of inhibition were measured after 48 hours incubation for aerobes and 96 hours incubation for anaerobes. Multiple one-way analyses of variance and post-hoc Student Neuman Keuls evaluated the data at alpha = 0.05. Larger zones of inhibition were consistently observed for higher concentrations of calcium hydroxide with statistical significance among the bacteria, particularly between 40% and 60%. Vitapex had significantly smaller zones of inhibition than all other medicaments and 35% UltraCal XS with methylcellulose was nearly as effective as 50% Ca(OH)(2) in inhibitory activity. Formulations containing 50-60% Ca(OH)(2) or 35% Ca(OH)(2) with aqueous methylcellulose are recommended as endodontic interappointment medicaments.

Antimicrobial effect of propolis and other substances against selected endodontic pathogens.

OBJECTIVE: The aim of this study was to determine the antimicrobial effect of ethanol extract of propolis (EEP) and intracanal medicaments calcium hydroxide, camphorated paramonochlorophenol, and formocresol by means of the macrodilution method using the reinforced clostridial medium (RCM) and brucella and brain heart infusion media. STUDY DESIGN: The antimicrobial agents were sequentially diluted and tested against anaerobic bacteria Prevotella nigrescens, Fusobacterium nucleatum, Actinomyces israelii, and Clostridium perfringens and against Enterococcus faecalis, with the 5 x 10(5) CFU/mL standardized inocula. The tubes were anaerobically incubated and the minimum inhibitory concentration was detected. Blood agar RCM subcultures were performed to provide minimum bactericidal concentration. The results were analyzed by analysis of variance test. RESULTS: All drugs were effective against all tested strains, without statistical differences. E. faecalis was the less susceptible strain, and RCM broth promoted faster bacterial growth, but there were no significant differences in these results. Ethanol did not influence the antimicrobial effect of EEP.

Effect of calcium hydroxide-treated Prevotella nigrescens on the gene expression of matrix metalloproteinase and its inhibitor in MG63 cells.

The purpose of this study was to monitor the expression of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) produced by an osteoblastic cell line MG63 stimulated with Prevotella nigrescens lipopolysaccharides (LPS), and to compare the level of secretion before and after the P. nigrescens LPS was treated with calcium hydroxide [Ca(OH)2]. The underlying hypothesis is that the balance between MMP and TIMP secretion is the key to an understanding of the host degradative pathways involved in the pathogenesis of bacterial derived pulpal and periapical diseases. Confluent monolayers of MG63 human osteosarcoma cells were exposed to varying concentrations of P. nigrescens or Escherichia coli LPS. Alternately, confluent cultures were exposed to 10 microg/ml of bacterial LPS pretreated with Ca(OH)2 (12.5 mg/ml) for 72 hours. At the end of the experimental period, total RNA was extracted and real-time quantitative polymerase chain reaction (PCR) was performed for MMP-1, TIMP-1, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The results showed that the expression of MMP-1 mRNA was low and invariant for the experimental period in the negative controls. However, exposure to P. nigrescens LPS increased expression after 48 hours. Expression of TIMP-1 mRNA was highly increased at 24 and 48 hours with lower concentrations of LPS in contrast to a suppression with a concentration of 10 microg/ml. Treatment of P. nigrescens LPS with Ca(OH)2 resulted in a down-regulation of MMP-1, whereas pretreated E. coli LPS demonstrated no stimulatory activity for MMP-1 gene expression. Both types of LPS when pretreated with Ca(OH)2 induced slightly up-regulated expression of TIMP-1.