Oral microbiota associated with gingiva of healthy, gingivitis and periodontitis cases.

Oral microbes coexist with each other in a symbiotic relationship or as commensals in healthy body. Teeth and oral cavity harbor diverse community of fungi and bacteria. This study focused on bacterial and fungal component of gingiva, where the last occupy little attention. In addition to study the antimicrobial activity of toothpastes, mouth washes and natural oils against microorganisms. Sixty swabs from outer surfaces of gingiva in healthy persons, as well as patients complaining of gingivitis and periodontitis were collected for fungal and bacterial analyses. Sensitivity of the isolated microorganisms to some pharmaceutical preparations and natural oils was also performed. Ten fungal and 9 bacterial species were identified. There is a highly significant variation in the frequency of Klebsiella pneumonia among healthy, gingivitis and periodontitis. Also, Candida tropicalis and cocci bacteria showed significant diversity among the three tested groups. Among pharmaceutical preparations (toothpastes and mouth washes) and natural oils, Paradontax, Hexitol and clove oil showed the best antimicrobial activity against tested fungal and bacterial strains. Although, minimum inhibition concentrations (MICs) of clove oil were high compared to Paradontax and Hexitol, nevertheless, it is highly recommended as both antifungal and antibacterial agent against oral pathogenic microorganisms, because it is a natural compound and nearly devoid of side effects.

Low-level laser-aided orthodontic treatment of periodontally compromised patients: a randomised controlled trial.

Low-level laser irradiation (LLLI) shows effects in orthodontic pain relief and periodontal inflammation control. The aim of this article is to investigate the analgesic and inflammation-modulatory effects of low-level laser irradiation among orthodontic patients with compromised periodontium. A randomised controlled trial with split-mouth design was conducted in 27 adults with treated and controlled chronic periodontitis over 6 months. One side of the dental arch underwent repeated treatment under a 940-nm diode laser (EZlase; Biolase Technology Inc.) with a beam size of 2.8 cm2 for 60 seconds at 8.6 J/cm2, whilst the other side received pseudo-laser treatment. Laser irradiation was applied repeatedly for 8 times during the first 6 weeks after bracket bonding and monthly thereafter until the end of orthodontic treatment. Subjective pain (assessed by visual analogue scale in pain diary and by chairside archwire activation), periodontal status (assessed by periodontal clinical parameters), cytokines in gingival crevicular fluid (interleukin 1ß, prostaglandin E2, substance P) and periodontopathic bacteria (Porphyromonas gingivalis and Treponema denticola) in supragingival plaque were assessed. The intensity of pain was lower on the laser-irradiated side at multiple follow-up visits (P < 0.05). The pain subsided 1 day earlier on the laser side, with a lower peak value during the first week after initial archwire placement (P < 0.05). The laser side exhibited a smaller reduction in bite force during the first month (mean difference = 3.17, 95% CI: 2.36-3.98, P < 0.05 at 1-week interval; mean difference = 3.09, 95% CI: 1.87-4.32, P < 0.05 at 1-month interval). A smaller increase was observed in the plaque index scores on the laser side at 1-month (mean difference = 0.19, 95% CI: 0.13-0.24, P < 0.05) and in the gingival index scores at the 3-month follow-up visit (mean difference = 0.18, 95% CI: 0.14-0.21, P < 0.05). Laser irradiation inhibited the elevation of interleukin-1ß, prostaglandin E2 and substance P levels during the first month (P < 0.05). However, no intergroup difference was detected in the bacteria levels. Low-level laser irradiation exhibits benefits in pain relief and inflammation control during the early stage of adjunctive orthodontic treatment in periodontally compromised individuals.

Investigation of Antibacterial and Antiinflammatory Activities of Proanthocyanidins from Pelargonium sidoides DC Root Extract.

The study explores antibacterial, antiinflammatory and cytoprotective capacity of Pelargonium sidoides DC root extract (PSRE) and proanthocyanidin fraction from PSRE (PACN) under conditions characteristic for periodontal disease. Following previous finding that PACN exerts stronger suppression of Porphyromonas gingivalis compared to the effect on commensal Streptococcus salivarius, the current work continues antibacterial investigation on Staphylococcus aureus, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans and Escherichia coli. PSRE and PACN are also studied for their ability to prevent gingival fibroblast cell death in the presence of bacteria or bacterial lipopolysaccharide (LPS), to block LPS- or LPS + IFNγ-induced release of inflammatory mediators, gene expression and surface antigen presentation. Both PSRE and PACN were more efficient in suppressing Staphylococcus and Aggregatibacter compared to Escherichia, prevented A. actinomycetemcomitans- and LPS-induced death of fibroblasts, decreased LPS-induced release of interleukin-8 and prostaglandin E2 from fibroblasts and IL-6 from leukocytes, blocked expression of IL-1ß, iNOS, and surface presentation of CD80 and CD86 in LPS + IFNγ-treated macrophages, and IL-1ß and COX-2 expression in LPS-treated leukocytes. None of the investigated substances affected either the level of secretion or expression of TNFα. In conclusion, PSRE, and especially PACN, possess strong antibacterial, antiinflammatory and gingival tissue protecting properties under periodontitis-mimicking conditions and are suggestable candidates for treatment of the disease.

Chemical effects of chewing sticks made of Salvadora persica.

OBJECTIVE: The chewing sticks are widely used in many regions of Asia and Africa as a traditional tool to maintain oral hygiene. Salvadora persica L. (S. persica), also known as Arak or Miswak, a member of the salvadoraceae family. Chewing sticks, made up from S. persica, have chemical antibacterial properties and mechanical effects. The study aimed to investigate possible chemical effects of S. persica on dental plaque, sub-gingival microbiota and gingival inflammation. In order to achieve this, we inactivated some sticks through boiling to be used as inactive, but mechanically comparable control sticks. METHODS: In a double-blinded crossover trial, 24 patients with mild-to-moderate periodontitis were randomly allocated to use either fresh activated Miswak or inactivated Miswak for 3-week period. Plaque index (PI), gingival index (GI), visual plaque index (VPI) and bleeding on probing (BOP) were evaluated before and immediately following the experimental period. Sub-gingival plaque samples were analysed using DNA-DNA hybridization technique. The study was repeated with the participants switching the type of Miswak they used after a 7-week of "washout" period. RESULTS: There were no significant differences in the microflora after using active and inactive Miswak. Sixteen species of bacteria showed an increase (P < 0.05) after the usage of inactive Miswak, as compared to pretreatment values. No species showed a similar change after the use of active Miswak. There were no significant differences between active and inactive Miswak regarding the registered clinical variables. CONCLUSION: This study has not shown any clinical effect of the chemically active Miswak, but there was a tendency towards an effect on the microflora.

Green tea polyphenols enhance gingival keratinocyte integrity and protect against invasion by Porphyromonas gingivalis.

The gingival epithelium, a stratified squamous tissue that acts as an interface between the external environment and the underlying connective tissue, plays an active role in maintaining periodontal health. The aim of the present study was to investigate the ability of green tea catechins to enhance gingival epithelial barrier function and protect against the disruption of epithelial integrity induced by Porphyromonas gingivalis. Both the green tea extract and epigallocatechin-3-gallate (EGCG) dose- and time-dependently increased the transepithelial electrical resistance (TER) of a gingival keratinocyte model and decreased the permeability of the cell monolayer to fluorescein isothyocyanate-conjugated 4.4-kDa dextran. This was associated with the increased expression of zonula occludens-1 (ZO-1) and occludin, two tight junction proteins. Treating the gingival keratinocyte monolayer with P. gingivalis caused a reduction in TER and affected the distribution of ZO-1 and occludin, allowing P. gingivalis to translocate through the cell monolayer. These deleterious effects mediated by P. gingivalis were abolished by the green tea extract and EGCG. This protection may be in part related to the ability of tea catechins to inhibit the protease activities of P. gingivalis. Given the above properties, green tea catechins may represent promising preventive and therapeutic molecules against periodontal disease.

Effects of green tea on miRNA and microbiome of oral epithelium.

Consumption of green tea (GT) extracts or purified catechins has shown the ability to prevent oral and other cancers and inhibit cancer progression in rodent models, but the evidence for this in humans is mixed. Working with humans, we sought to understand the source of variable responses to GT by examining its effects on oral epithelium. Lingual epithelial RNA and lingual and gingival microbiota were measured before and after 4 weeks of exposure in tobacco smokers, whom are at high risk of oral cancer. GT consumption had on average inconsistent effects on miRNA expression in the oral epithelium. Only analysis that examined paired miRNAs, showing changed and coordinated expression with GT exposure, provided evidence for a GT effect on miRNAs, identifying miRNAs co-expressed with two hubs, miR-181a-5p and 301a-3p. An examination of the microbiome on cancer prone lingual mucosa, in contrast, showed clear shifts in the relative abundance of Streptococcus and Staphylococcus, and other genera after GT exposure. These data support the idea that tea consumption can consistently change oral bacteria in humans, which may affect carcinogenesis, but argue that GT effects on oral epithelial miRNA expression in humans vary between individuals.

Low antibiotic resistance among anaerobic Gram-negative bacteria in periodontitis 5 years following metronidazole therapy.

The objective of this study was to assess antibiotic susceptibility among predominant Gram-negative anaerobic bacteria isolated from periodontitis patients who 5 years prior had been subject to mechanical therapy with or without adjunctive metronidazole. One pooled sample was taken from the 5 deepest sites of each of 161 patients that completed the 5 year follow-up after therapy. The samples were analyzed by culture. A total number of 85 anaerobic strains were isolated from the predominant subgingival flora of 65/161 patient samples, identified, and tested for antibiotic susceptibility by MIC determination. E-tests against metronidazole, penicillin, amoxicillin, amoxicillin + clavulanic acid and clindamycin were employed. The 73/85 strains were Gram-negative rods (21 Porphyromonas spp., 22 Prevotella/Bacteroides spp., 23 Fusobacterium/Filifactor spp., 3 Campylobacter spp. and 4 Tannerella forsythia). These were all isolated from the treated patients irrespective of therapy procedures (+/-metronidazole) 5 years prior. Three strains (Bifidobacterium spp., Propionibacterium propionicum, Parvimonas micra) showed MIC values for metronidazole over the European Committee on Antimicrobial Susceptibility Testing break point of >4 µg/mL. All Porphyromonas and Tannerella strains were highly susceptible. Metronidazole resistant Gram-negative strains were not found, while a few showed resistance against beta-lactam antibiotics. In this population of 161 patients who had been subject to mechanical periodontal therapy with or without adjunct metronidazole 5 years prior, no cultivable antibiotic resistant anaerobes were found in the predominant subgingival microbiota.

Evaluation of antimicrobial photodynamic therapy with indocyanine green and curcumin on human gingival fibroblast cells: An in vitro photocytotoxicity investigation.

UNLABELLED: Recent investigations have suggested that antimicrobial photodynamic therapy (aPDT) can be an alternative treatment for the management of periodontal infections. However, currently there is very limited data regarding the photocytotoxicity of this method on human gingival fibroblast (HuGu) cells. AIM: The in vitro optimal concentrations of indocyanine green (ICG) and curcumin as photosensitizers (PSs) and the irradiation time of diode laser emission were evaluated by assessing the photocytotoxicity of the treatment on HuGu cells. MATERIALS AND METHOD: Monolayers of HuGu cells were incubated with various final concentrations of ICG (500, 750, 1000, 1250, 1500, 1750, and 2000µg/ml) and curcumin (3, 4, 5, 10, and 20mM). Three exposure times of the diode laser (30s, 60s, and 2×30s irradiation with an interval of 1min between each) and one of exposure time of 5min for LED were tested; cell viability was determined using neutral red assay. Chlorhexidine (CHX) as a gold standard antimicrobial agent for periodontal disease was considered as a control group. RESULTS: ICG and curcumin significantly reduced HuGu cell viability at concentrations below 1000µg/ml and 10mM, respectively (P<0.01). Cytotoxicity was higher when the cells were treated for 2×30s irradiation with an interval of 1min and then again exposed to the laser for 30s (2% and 0.1%). CHX demonstrated no significant reduction in HuGu cell survival. CONCLUSION: Photocytotoxicity is influenced by PS concentration, exposure time of PS, and time of irradiation. High doses of ICG and curcumin with lowest exposure time of light source and without cytotoxic effects may be an effective strategy for aPDT as an alternative treatment for periodontal disease.

Antimicrobial photodynamic effect to treat residual pockets in periodontal patients: a randomized controlled clinical trial.

AIM: A randomized controlled clinical trial was designed to evaluate the efficacy of the photodynamic therapy (PDT) in the treatment of residual pockets of chronic periodontitis patients. MATERIAL AND METHODS: Thirty-four patients with at least four residual periodontal pockets undergoing maintenance care were included and randomly assigned to test group (PDT, n = 18) or control group (sham procedure, n = 16). The intervention was performed at baseline, 3, 6 and 12 months. Clinical parameters such as pocket probing depth (PPD), clinical attachment level (CAL), bleeding on probing (BoP) and plaque index (PI) were measured before intervention and after 3, 6 and 12 months. Subgingival samples were obtained at baseline, and after 7 days, 3, 6 and 12 months to quantify Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia by real-time polimerase chain reaction (PCR). RESULTS: All clinical variables showed significant improvement during the study, but there was no significant difference between test and control groups. The microbiological analyses showed no differences between groups at any time during the study. CONCLUSION: Within the limits of this clinical trial and considering the laser and photosensitizer protocol used, PDT failed to demonstrate additional clinical and bacteriological benefits in residual pockets treatment.

The Effect of Pistacia atlantica Var. mutica Mouthwash on Dental Plaque Bacteria and Subgingival Microorganisms: a Randomized and Controlled Triple-blind Study.

Dental plaque is a well-documented etiologic factor for periodontal diseases. While chlorhexidine (CHX) is the gold-standard agent for treating dental plaques, undesirable side effects are often found after continuous use of the mouthwash. Therefore, this single-center, randomized, triple-blinded and clinical trial was undertaken to evaluate the efficacy of Pistacia atlantica Var. mutica extract mouthwash on de novo dental plaque bacteria and subgingival microorganisms compared to CHX on a total of 28 patients. The mean aerobic plaque bacterial count of patients at baseline was 2.17 × 10(6). After 4 days of treatment, there were statistically significant decreases in the mean aerobic bacteria in the patients who received P. atlantica and/or CHX (7.25 × 10(4), p = 0.006) and (9.91 × 10(3), p = 0.002), respectively, compared to the patients who received the placebo (6.26 × 10(5)). This study showed that P. atlantica mouthwash is effective against gingival microorganisms. Because of its reduced side effects, P. atlantica mouthwash may be a good alternative choice for patients.

Phototargeting human periodontal pathogens in vivo.

The effects of blue light at 455 nm were investigated on the bacterial composition of human dental plaque in vivo. Eleven subjects who refrained from brushing for 3 days before and during phototherapy participated in the study. Light with a power density of 70 mW/cm(2) was applied to the buccal surfaces of premolar and molar teeth on one side of the mouth twice daily for 2 min over a period of 4 days. Dental plaque was harvested at baseline and again at the end of 4 days from eight posterior teeth on both the exposed side and unexposed sides of the mouth. Microbiological changes were monitored by checkerboard DNA probe analysis of 40 periodontal bacteria. The proportions of black-pigmented species Porphyromonas gingivalis and Prevotella intermedia were significantly reduced on the exposed side from their original proportions by 25 and 56 %, respectively, while no change was observed to the unexposed side. Five other species showed the greatest proportional reduction of the light-exposed side relative to the unexposed side. These species were Streptococcus intermedius, Fusobacterium nucleatum ss. vincentii, Fusobacterium nucleatum ss. polymorphum, Fusobacterium periodonticum, and Capnocytophaga sputigena. At the same time, the percentage of gingival areas scored as being red decreased on the side exposed to light from 48 to 42 %, whereas the percentage scored as red increased on the unexposed side from 53 to 56 %. No adverse effects were found or reported in this study. The present study proposes a new method to modify the ecosystem in dental plaque by phototherapy and introduces a new avenue of prophylactic treatment for periodontal diseases.

Peptidylarginine deiminase from Porphyromonas gingivalis contributes to infection of gingival fibroblasts and induction of prostaglandin E2 -signaling pathway.

Porphyromonas gingivalis (P. gingivalis) expres-ses the enzyme peptidylarginine deiminase (PPAD), which has a strong preference for C-terminal arginines. Due to the combined activity of PPAD and Arg-specific gingipains, P. gingivalis on the cell surface is highly citrullinated. To investigate the contribution of PPAD to the interaction of P. gingivalis with primary human gingival fibroblasts (PHGF) and P. gingivalis-induced synthesis of prostaglandin E2 (PGE2 ), PHGF were infected with wild-type P. gingivalis ATCC 33277, an isogenic PPAD-knockout strain (∆ppad) or a mutated strain (C351A) expressing an inactive enzyme in which the catalytic cysteine has been mutated to alanine (PPAD(C351A) ). Cells were infected in medium containing the mutants alone or in medium supplemented with purified, active PPAD. PHGF infection was assessed by colony-forming assay, microscopic analysis and flow cytometry. Expression of cyclo-oxygenase 2 (COX-2) and microsomal PGE synthase-1 (mPGES-1), key factors in the prostaglandin synthesis pathway, was examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR), while PGE2 synthesis was evaluated by enzyme immunoassay. PHGF were infected more efficiently by wild-type P. gingivalis than by the ∆ppad strain, which correlated with strong induction of COX-2 and mPGES-1 expression by wild-type P. gingivalis, but not by the PPAD activity-null mutant strains (Δppad and C351A). The impaired ability of the Δppad strain to adhere to and/or invade PHGF and both Δppad and C351A to stimulate the PGE2 -synthesis pathway was fully restored by the addition of purified PPAD. The latter effect was strongly inhibited by aspirin. Collectively, our results implicate PPAD activity, but not PPAD itself, as an important factor for gingival fibroblast infection and activation of PGE2 synthesis, the latter of which may strongly contribute to bone resorption and eventual tooth loss.

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.

Protective effect of topical Cordia verbenacea in a rat periodontitis model: immune-inflammatory, antibacterial and morphometric assays.

BACKGROUND: This study evaluated the effects of C. verbenacea essential oil topically administered in a rat periodontitis model. METHODS: Periodontitis was induced on rats in one of the mandibular first molars assigned to receive a ligature. Animals were randomly divided into two groups: a) non-treatment group (NT) (n = 18): animals received 1mL of vehicle; b) C. verbenacea group (C.v.) (n = 18): animals received 5mg/Kg of essential oils isolated from C. verbenacea. The therapies were administered topically 3 times daily for 11 days. Then, the specimens were processed for morphometric analysis of bone loss. The ligatures were used for microbiological assessment of the presence of Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Porphyromonas gingivalis using PCR. The gingival tissue was collected to Elisa assay of interleukin (IL)-1α and IL-10 levels. RESULTS: Bone loss was inhibited by C. verbenacea when compared to the NT group (p < 0.05). A decrease in the levels of IL-1α and increase in the IL-10 amounts was observed in the C.v. group as compared to NT group (p < 0.05). A lower frequency of P. gingivalis was found in C.v. group (p < 0.05). CONCLUSION: C. verbenacea essential oil topically administered diminished alveolar bone resorption, promoting a positive local imbalance in the pro/anti-inflammatory system and reducing the frequency of detection of P. gingivalis.

Effects of fruit and vegetable low molecular mass fractions on gene expression in gingival cells challenged with Prevotella intermedia and Actinomyces naeslundii.

Low molecular mass (LMM) fractions obtained from extracts of raspberry, red chicory, and Shiitake mushrooms have been shown to be an useful source of specific antibacterial, antiadhesion/coaggregation, and antibiofilm agent(s) that might be used for protection towards caries and gingivitis. In this paper, the effects of such LMM fractions on human gingival KB cells exposed to the periodontal pathogens Prevotella intermedia and Actinomyces naeslundii were evaluated. Expression of cytokeratin 18 (CK18) and ß4 integrin (ß4INT) genes, that are involved in cell proliferation/differentiation and adhesion, and of the antimicrobial peptide ß2 defensin (HßD2) in KB cells was increased upon exposure to either live or heat-killed bacteria. All LMM fractions tested prevented or reduced the induction of gene expression by P. intermedia and A. naeslundii depending on the experimental conditions. Overall, the results suggested that LMM fractions could modulate the effects of bacteria associated with periodontal disease in gingival cells.

Short term clinical effect of active and inactive Salvadora persica miswak on dental plaque and gingivitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Salvadora persica shrub has been used traditionally in folk medicine for different medical condition treatments. The habitual use of Salvadora persica roots (chewing sticks) for dental hygiene is still wildly spread throughout parts of Asia, Africa, and Middle. It is one of the most important species with its reported strong antibacterial, antifungal, and antiviral effects. Mechanical removal of dental plaque is regarded as an effective mean of controlling progression of periodontal disease. AIM OF THE STUDY: To evaluate the effect of active and inactive miswak on dental plaque, subgingival microbiota and gingival inflammation in patients with gingivitis. MATERIALS AND METHODS: In this double blinded randomized controlled trial 68 gingivitis patients were randomly assigned to either active or inactive miswak group, and were instructed to use only issued miswaks for oral hygiene during 3 weeks experimental period. Registration of plaque, gingival inflammation, and plaque samples were taken at baseline and on completion of the study. Plaque samples were analyzed by DNA-DNA hybridization technique. RESULTS: Active miswak significantly reduced dental plaque (p = 0.007). There were no differences between active and inactive miswak in reduction of approximal plaque and composition of subgingival microbiota. CONCLUSIONS: Miswak has an overall effect on dental plaque and gingival inflammation scores. Similar results were achieved by active and inactive miswak in difficult to reach areas, indicating miswak has limited chemical effects on this study population. Therefore, miswak can be used as a dental hygiene method in conjunction with interproximal cleaning aides.

Effect of khat chewing on periodontal pathogens in subgingival biofilm from chronic periodontitis patients.

AIMS: Existing in vitro and in vivo data suggest that khat may have a favorable effect on periodontal microbiota. The purpose of this study was to assess the effect of khat chewing on major periodontal pathogens in subgingival plaque samples from subjects with chronic periodontitis. MATERIALS AND METHODS: 40 subgingival plaque samples were obtained from periodontitis and healthy sites of 10 khat chewers (40 y median age) and 10 khat non-chewers (37.5 y median age) with chronic periodontitis. Absolute and relative counts of 6 periodontal pathogens were determined in each sample using highly sensitive and specific Taqman real-time PCR assays. Data were analyzed using an ordinal regression model. RESULTS: Significantly more total bacteria were detected in samples from the periodontitis sites of the khat chewers (OR=20). Treponema denticola was present at significantly higher absolute counts at the healthy as well as periodontitis sites of the khat chewers (OR=3.13 and 13, respectively). However, the khat chewers harbored significantly lower absolute counts of Porphyromonas gingivalis at the healthy sites (OR=0.07). Furthermore, khat chewing was significantly associated with lower relative counts of Porphyromonas gingivalis, fusobacterium ssp., prevotella ssp. and Parvimonas micra-like species in subgingival plaque samples from both healthy and periodontitis sites (OR=0.11-0.33). Only Treponema denticola was found in higher relative counts at the healthy sites of the khat chewers (OR=2.98). CONCLUSIONS: Overall, there was a lower burden of pathogens in the khat chewers. Findings from the current study are suggestive of a potential prebiotic effect for khat on periodontal microbiota.

Suppressive effect of ethanolic Kaempferia pandurata Roxb. extract on matrix metalloproteinase-2 expression in Porphyromonas gingivalis-treated human gingival fibroblasts in vitro.

In periodontal disease, gingival fibroblasts activated by the Gram-negative anaerobic bacterium Porphyromonas gingivalis induce overexpression of matrix metalloproteinase-2 (MMP-2), which is involved in inflammatory progression. This process is followed by tissue destruction and bone loss. In the present study, we investigated the in vitro effect of the ethanolic Kaempferia pandurata Roxb. extract on expression of MMP-2 in P. gingivalis-treated human gingival fibroblast-1 (HGF-1) cells. In addition, we utilized gelatin zymography, Western blotting, and reverse transcription-PCR analysis to elucidate the molecular mechanisms underlying MMP-2 inhibition via the mitogen-activated protein kinase (MAPK) and cyclic AMP response element-binding protein (CREB) signaling pathways. Treatment with K. pandurata extract (1-10 µg/ml) dose-dependently suppressed the activity, secretion, and protein expression of MMP-2 in HGF-1 cells exposed to P. gingivalis. At the transcriptional level, inhibition of MMP-2 gene expression by K. pandurata was mediated by phosphorylation of c-Jun N-terminal kinase (JNK) and CREB signaling pathways in P. gingivalis-treated HGF-1 cells. These results suggest that K. pandurata extract suppresses MMP-2 expression at the protein and gene levels via downregulation of the principal JNK and CREB signaling pathways. Due to its efficacy in inhibiting MMP-mediated periodontal destruction, K. pandurata might represent a new, potent periodontal therapy.

Protective effect of locally applied carvacrol gel on ligature-induced periodontitis in rats: a tapping mode AFM study.

The aims of this study were to test a locally applied carvacrol gel and determine its efficacy preventing alveolar bone loss in experimental periodontitis in rats by regular methodology to validate applicability the atomic force microscopy (AFM) as a novel morphology method on this model. Wistar rats were subjected to ligature around second, upper-left molars. Animals were treated carvacrol gel topically (CAG), immediately after Experimental Periodontitis Disease induction for 1' three-times/day for 11 days. A vehicle gel was utilized as control. The periodontium and the surrounding gingivae were examined at regular histopathology and by AFM method; the neutrophil influx into the gingivae was also assayed using myeloperoxidase activity. The bacterial flora was assessed through culture of the gingival tissue. Alveolar bone loss was significantly inhibited by CAG group compared to the Vehicle (V) group, the carvacrol gel treatment reduced tissue lesion at histopathology, with preservation of the periodontium, coupled to decreased myeloperoxidase activity in gingival tissue and also prevented the proliferation of periodontal microorganisms and the weight loss. The GAC treatment preserved alveolar bone resorption and showed anti-inflammatory and antibacterial activities in experimental periodontitis. Topographical changes in histological sections were seen bringing into high relief the periodontal structures, being a simple and cost-effective method for periodontal evaluation with ultrastructural resolution.

Microbiological evaluation of the effects of hyperbaric oxygen on periodontal disease.

The term periodontitis indicates a variety of clinical manifestations of infectious disorders in which the supporting tissues of the teeth are attacked. The initiation and progression of periodontal disease are attributed to the presence of elevated levels of pathogenic bacteria within the gingival crevice. Approaches to periodontal treatment range from surgical to regenerative therapy and anti-infective chemotherapy. Anti-infective drug therapy should be rationally based on the composition of the pathogenic microbiota. It is also important to recognize that the periodontopathic plaque constitutes a bacterial biofilm infection that may render the resident microorganisms more resistant than the same organisms grown planktonically. Hyperbaric oxygen (HBO) has been successfully used in several medical applications. The therapeutic effect is related to elevated partial oxygen pressure in the tissues. The aim of this study was to evaluate the effects of HBO on a selected number of patients suffering from adult chronic periodontitis in comparison with surgical intervention (scaling and root planning, SRP), as well as the effects of a combination of both therapies on the evolution over time of the microflora of the periodontal pockets. Bacteria were detected either by culture or by a molecular method (PCR). Microbiological data indicate that the combination of HBO and SRP substantially reduced (by up to 99.9%) the gram-negative anaerobe loads of the subgingival microflora. The low values of pathogens persisted for at least two months after the therapy. HBO or SRP alone produced a temporarily more limited effect on periodontal anaerobes. Additional experimental confirmation of these results was provided by molecular detection of the main periodontopathogenic bacteria with a significant reduction in the number of dental sites which harboured them. It is also shown that HBO both alone and in combination with SRP reduced the Gingival Index value to zero and gingival health persisted for 3 months at least. Thus, in parallel with the loss of periodontopathogenic bacteria, a substantial improvement in oral health was observed. In conclusion, this study has shown that HBO may represent a useful aid, especially in combination with SRP, as far as non-surgical periodontal therapy is concerned.