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PubMed2006

Effect of material characteristics and/or surface topography on biofilm development.

BACKGROUND: From an ecological viewpoint, the oral cavity, in fact the oro-pharynx, is an 'open growth system'. It undergoes an uninterrupted introduction and removal of both microorganisms and nutrients. In order to survive within the oro-pharyngeal area, bacteria need to adhere either to the soft or hard tissues in order to resist shear forces. The fast turn-over of the oral lining epithelia (shedding 3 x/day) is an efficient defence mechanism as it prevents the accumulation of large masses of microorganisms. Teeth, dentures, or endosseous implants, however, providing non-shedding surfaces, allow the formation of thick biofilms. In general, the established biofilm maintains an equilibrium with the host. An uncontrolled accumulation and/or metabolism of bacteria on the hard surfaces forms, however, the primary cause of dental caries, gingivitis, periodontitis, peri-implantitis, and stomatitis. OBJECTIVES: This systematic review aimed to evaluate critically the impact of surface characteristics (free energy, roughness, chemistry) on the de novo biofilm formation, especially in the supragingival and to a lesser extent in the subgingival areas. METHODS: An electronic Medline search (from 1966 until July 2005) was conducted applying the following search items: 'biofilm formation and dental/oral implants/surface characteristics', 'surface characteristics and implants', 'biofilm formation and oral', 'plaque/biofilm and roughness', 'plaque/biofilm and surface free energy', and 'plaque formation and implants'. Only clinical studies within the oro-pharyngeal area were included. RESULTS: From a series of split-mouth studies, it could be concluded that both an increase in surface roughness above the R(a) threshold of 0.2 microm and/or of the surface-free energy facilitates biofilm formation on restorative materials. When both surface characteristics interact with each other, surface roughness was found to be predominant. The biofilm formation is also influenced by the type (chemical composition) of biomaterial or the type of coating. Direct comparisons in biofilm formation on different transmucosal implant surfaces are scars. CONCLUSIONS: Extrapolation of data from studies on different restorative materials seems to indicate that transmucosal implant surfaces with a higher surface roughness/surface free energy facilitate biofilm formation.

Bacterial Adhesion↗

PubMedDate not supplied

Microbiota around root-form endosseous implants: a review of the literature.

Although high success rates for root-form endosseous implants have been reported, failures occasionally occur, and these implants must be removed. At least 10% of the failures have been suggested to be the result of peri-implantitis. There is some evidence that periodontal pathogens, mainly those belonging to the group of gram-negative anaerobic rods, play a role in the etiology of peri-implantitis. This article provides an overview of the literature associated with common peri-implant microbiology and an assessment as to whether bacteria associated with periodontitis exert a possible risk for peri-implant tissue breakdown. The peri-implant area is colonized by a large variety of oral microbial complexes. The microflora of the oral cavity prior to implant placement determines the composition of the microflora in the peri-implant area. Implants involved in peri-implantitis are colonized with large amounts of gram-negative anaerobic bacteria, including Fusobacteria, spirochetes, Bacteroides forsythus, and "black-pigmented bacteria" such as Prevotella intermedia, Prevotella nigrescens, and Porphyromonas gingivalis. Also, Actinobacillus actinomycetemcomitans can be isolated from these lesions. Thus, the microflora of peri-implantitis lesions resembles that of adult or refractory periodontitis. However, the presence of periodontal pathogens does not always lead to a destructive process. Therefore, the etiologic role of specific microorganisms in implant failure related to infection is still not resolved. Controversy remains as to whether organisms recovered from the original microflora cause the failure (and if so to what extent) or merely result from the infection. Nevertheless, there is accumulating evidence that bacteria cause the disease, while the individual's genetic makeup and environmental influences determine the severity of the disease.

Dental Implantation, Endosseous↗

PubMed2005

Detection of Actinobacillus actinomycetemcomitans in unstimulated saliva of patients with chronic periodontitis.

BACKGROUND: The use of whole saliva has shown to be promising in detecting Actinobacillus actinomycetemcomitans out of the subgingival environment. The objective of the present study was to evaluate the use of unstimulated saliva in detecting A. actinomycetemcomitans and to compare the subgingival and extracrevicular occurrence of this pathogen in Brazilian subjects with chronic periodontitis. METHODS: Sixty-six patients (mean age 38.01 9.28 years) with advanced generalized chronic periodontitis were sampled. Subgingival plaque samples were collected from eight sites per patient representing the two deepest sites of each quadrant. Samples of the mucous surfaces, including dorsal surface of the tongue and cheek, were collected with a sterile swab and placed in a microtube containing a reduced solution. Samples of unstimulated saliva were also collected in sterile tubes and 0.1 ml of whole saliva was diluted in 1 ml of reduced solution. The presence of A. actionomycetemcomitans was established using bacterial culture in trypticase soy bacitracin vancomycin selective media. Polymerase chain reaction (PCR) was used to differentiate highly from minimally leukotoxic strains in patients who presented A. actinomycetemcomitans in at least two sampled sites. RESULTS: A. actinomycetemcomitans was isolated from 63.63% of subgingival samples, 56.06% of saliva samples, and 45.45% of samples from mucous surfaces. No statistical difference was observed between subgingival and salivary occurrence of the microorganism. Linear regression showed an association between subgingival plaque and saliva (r(2) = 0.897; P = 0.015) and mucous membrane and saliva (r(2) = 0.152; P = 0.024). The same A. actinomycetemcomitans leukotoxic profile was observed in all sampled sites for a given patient. CONCLUSION: These results suggest that in advanced periodontitis, unstimulated saliva is representative of pooled subgingival plaque samples and its use is appropriate in the oral detection of A. actinomycetemcomitans.

Adult↗

PubMed2004

Helicobacter pylori and food products: a public health problem.

Helicobacter pylori is a major human pathogen causing gastritis and chronic superficial infection (CSG). It colonizes the stomach of more than 50% of humans and causes disease. This microorganism is associated with the gastric antral epithelium in patients with active chronic gastritis, peptic (gastric) or duodenal ulcers, and gastric adenocarcinoma H. pylori is present in feces, sewage, and water but is killed by routine chlorination. Therefore, in developing countries, consumption of sewage-contaminated drinking water and vegetables may pose a risk; properly cooking foods and chlorinating water reduces the risk of transmitting H. pylori to humans. In South America the consumption of raw vegetables fertilized with human feces has been found to be a risk factor for infection, and consumption of water from a municipal supply has been suggested as a risk factor for children. Epidemiological studies have found that H. pylori organisms colonize the stomach and duodenum of humans and many animal species and family clusters; it is believed to be orally transmitted person to person. This transmission is the major, if not exclusive, source of infection.H. pylori has been detected in the mouth from dental plaque. Recent observations in persons infected with H. pylori caused to vomit or have diarrhea showed that an actively unwell person with these symptoms could spread H. pylori in the immediate vicinity by aerosol, splashing of vomitus, infected vomitus, and infected diarrhea. In summary, H. pylori is usually spread by the fecal-oral route but possibly also by the oral-oral route and the spread of contaminated secretions. Thus, in developing countries, individuals catch H. pylori at a very young age from other persons (children) in their environment. In developed countries, H. pylori is more difficult to acquire and is usually transmitted from one family member to another, possibly by the fecal-oral route, or by the oral-oral route, e.g., kissing, vomitus. On occasion, transmission occurs from person to person via contaminated endoscopes. Other gastric Helicobacter-like organisms have now been observed in a variety of animals, including rodents, primates, swine, and ferrets, but, with the exception of primates and possibly cats, these isolates are clearly different from human isolates. Foodborne transmission would not be unusual.

Breath Tests↗

PubMedDate not supplied

[Sanitaro-microbiologic aspects of the concurrent residence of man and animals in hermetic quarters].

Men and animals (dogs) shared an enclosed environment for 30 days. The microorganisms on their skin and in the air were examined. Specific attention was given to staphylococcal pathogens that are potential causal agents of infectious diseases in enclosed bio-objects. The data obtained suggest that conditional pathogens can be exchanged between men and animals sharing an environment and clarify the mechanism(s) of their transfer. The experimental results have been used to develop prophylactic measures against diseases caused by conditional pathogens among men and animals sharing an enclosed environment.

Air Microbiology↗

PubMed1991

Oral ecology and its pathogenic relation with the origin of primary periodontitis associated with plaque.

Microbial factors involved in the genesis of periodontitis are related with supragingival (coronal) and subgingival plaque. The microorganisms in the supragingival plaque reach the gingival sulcus, and are influenced by ecological determinants in this zone which condition the establishment of adherent plaque. This plaque may subsequently form the substrate for particularly periodon to pathogenic bacteria, which may then form plaques adhered to the epithelium, or develop as floating (nonadhered) populations. After microbial colonization of the gingival sulcus, bacteria or substances they produce may reach the junctional epithelium and alveolar bone, leading to direct tissular destruction to an extent determined by the host's immune response. Damage may be local or generalized, depending on additional factors.

Dental Plaque↗

PubMed1988

[Use of standardized oral hygiene in the prevention and therapy of mucositis in patients treated with radiochemotherapy of head and neck neoplasms].

Aseptic mucositis is a regularly occurring complication during radiochemotherapy of head and neck cancer. In case of a superinfection with pathogenic microorganisms the degree of mucositits can make an interruption of cancer therapy imperative. It may also cause severe complications such as fulminating fatal infection, local spreading to the oesophagus and even mediastinitis as well as disseminated fungal infections. We investigated the effect of the systematic local combined application of H202, povidone iodine, nystatine and dexpanthenol solution for the prophylaxis and therapy of mucositis induced by radiochemotherapy. During 16 months of application of our scheme symptoms of mucositis appeared only to a minor extent. No interruption of radiochemotherapy was necessary at any time.

Combined Modality Therapy↗

PubMed2004

Time of initial acquisition of mutans streptococci by human infants.

The aim of this study was to detect and monitor the acquisition of mutans streptococci (MS) in healthy Brazilian children. Samples of 4 different sites (saliva, tongue dorsum, dental ridges, and dental plaque, if teeth were present) were collected from 33 edentulous nursery school infants (5.9+/-1.5 month-old), using sterilized swabs, bi-monthly for 24 months. Saliva samples from the mothers were collected only once. After inoculation, and incubation typical morphotype colonies, were isolated and submitted to amplification by the technique of polymerase chain reaction (PCR) for identification. The PCR method identified 1667 strains as MS In 29 of the children's samples, the first positive culture for MS occurred at 15.3+/-4.6 months. At the end of the follow-up period, 77% of the children were classified as colonized and in 33% MS was found as a transient microorganism. A positive correlation was found between the time of MS acquisition by the infant and the number of erupted teeth (p<0.0001), and the time of emergence of the first tooth (p=0.0048). After 24 months, there were no dental caries, and 77% of children remained caries-free. These results indicate that MS colonization in this sample of low-income pre-school children may begin earlier than suggested by some investigations.

Age Factors↗

PubMedDate not supplied

[The morphological characteristics of the interaction of parietal microflora with the mucosal epitheliocytes of the alveolar crest in patients with partially missing teeth].

Microbiopsy specimens of the alveolar ridge obtained at the sites of missing teeth from patients and similar autopsy specimens from those dead without apparent oral and gastrointestinal diseases were examined electron microscopically in order to elucidate the interactions between the oral mucosa parietal microflora and epitheliocytes. Cocci-like microorganisms and microorganisms resembling Candida-like yeast by their ultrastructure were as a rule seen on the surface of the horny layer. The results evidence that loss of teeth involves the appearance of quite a number of various parietal bacteria in the oral mucosa, inducing characteristic changes in the pricky and horny layer cells. Intracellular location of the bacteria also contributes here. All this should be borne in mind when choosing the denture design. Antibacterial therapy appears to be advisable before fitting the patients with dentures.

Alveolar Process↗

PubMed2002

Influence of calcium hydroxide root-canal sealer on microbial growth in vitro.

The calcium hydroxide-based filling material Apexit, which is often used in endodontic practice, was evaluated for its antibacterial and antifungal effects against microorganisms isolated from oral cavity (Serratia marcescens, Pseudomonas putida, Staphylococcus aureus, Candida albicans). Two different quantitative techniques were employed--the direct-contact test was used to examine the efficacy of freshly mixed material while the broth-survival test was employed to check the antimicrobial properties of 5-d-old material. Apexit inhibited Gram-negative bacteria more effectively than Gram-positive ones but had none or a very weak inhibitory effect on C. albicans.

Anti-Bacterial Agents↗

PubMed2000

Photoactive porphyrin derivative with broad-spectrum activity against oral pathogens In vitro.

Photodynamic therapy (PDT) has historically been used as a means to treat cancerous tumors but has recently been used to kill bacterial cells through the use of targeted photosensitizers. PDT is a potential adjunct to scaling and root planing in the treatment of periodontal disease. However, the effectiveness of porphyrin derivatives against microorganisms has been limited because some gram-negative bacteria are refractory to photodynamic treatment with these agents. We have designed a porphyrin derivative conjugated to a pentalysine moeity that endows the molecule with activity against gram-positive and gram-negative bacteria. Whereas the porphyrin, chlorin e6, showed in vitro activity against a limited spectrum of bacteria, chlorin e6 conjugated to pentalysine showed in vitro activity against all oral microorganisms tested, including Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum subsp. polymorphum, Actinomyces viscosus, and the streptococci. Potent antimicrobial activity (>/=5-log-unit reduction in the numbers of CFU per milliliter) was retained in the presence of up to 25% whole sheep blood. The use of potent, selective agents such as this chlorin e6-pentalysine conjugate to more effectively reduce the pathogenic bacteria in the periodontal pocket may be a significant tool for the treatment of periodontal disease.

Aggregatibacter actinomycetemcomitans↗

PubMed1982

Phagocytic and killing activity of human blood, gingival crevicular, and salivary polymorphonuclear leukocytes for oral streptococci.

The phagocytosis and killing of oral streptococci by blood, crevicular, and salivary polymorphonuclear leukocytes (PMNL) were examined using a visual assay based on differential staining of viable and non-viable microorganisms by acridine orange. Crevicular PMNL were 83% viable, 19% contained bacteria on collection, and phagocytosis occurred in vitro in 66% of glass-adherent leukocytes. Salivary PMNL were 56% viable, 11% contained bacteria on collection, and 44% phagocytosed streptococci in vitro. Crevicular and salivary PMNL were capable of phagocytosis and killing of oral streptococci, but both were impaired. Crevicular fluid was not significantly leukotoxic; mixed saliva caused a significant reduction in PMNL viability and in phagocytic and killing activity for oral streptococci. Crevicular PMNL may be actively functional phagocytes, but salivary PMNL are unlikely to be significant in oral defenses.

Animals↗

PubMed1991

Adhesion of Candida albicans to epithelial cells effect of polyoxin D.

Data from our previous studies suggested that the fungal cell wall component, chitin, is involved in the adhesion of Candida albicans to mucosal surfaces. In the present study, we investigated the effect of polyoxin D, an inhibitor of chitin synthase, on the interaction of the fungus with epithelial cells. The effect of polyoxin D on Candida was evaluated in in vitro assays for its capacity to adhere to buccal epithelial cells (BEC), and by fluorescent-microscopy photometry and flow cytometry using cells stained with cellufluor (CF), a fluorochrome with affinity for chitin. C. albicans grown with and without polyoxin D was stained with CF and examined in a fluorescent microscope equipped with a photometer. Measurements of fluorescence revealed a wide range of intensity among C. albicans cells and a decreased intensity in polyoxin D treated cultures. Flow cytometry analyses of yeasts revealed 2 peaks of fluorescence intensity, and pointed to differences between polyoxin D treated and non-treated microorganisms. C. albicans stained with CF were separated into 2 subpopulations by flow cytometry according to fluorescence intensity. In vitro adhesion of each subpopulation to BEC was similar. Polyoxin D treated fungi showed significantly reduced adherence to BEC, as evaluated by a radioactivity assay with radiolabelled yeasts and by microscopic readings. The reduction in adhesion was Polyoxin D concentration dependent. These observations support our previous findings suggesting involvement of chitin in the attachment process of C. albicans (CBS562) to epithelial cells.

Antifungal Agents↗

PubMed2000

The oral cavity as a reservoir of bacterial pathogens for focal infections.

Dental procedures, but more importantly, oral infections and poor oral health can provoke the introduction of oral microorganisms into the bloodstream or the lymphatic system. The subsequent attachment and multiplication of these bacteria on tissues or organs can lead to focal oral infections. Pathogenic agents may also remain at their primary oral site but the toxins liberated can reach an organ or tissue via the bloodstream and cause metastatic injury. Finally, metastatic inflammation may result from an immunological injury caused by oral bacteria or their soluble products that enter the bloodstream and react with circulating specific antibodies to form macromolecular complexes.

Bacteremia↗

PubMed1999

Candida albicans triggers interleukin-6 and interleukin-8 responses by oral fibroblasts in vitro.

Oral candidiasis is the most frequent opportunistic infection associated with an immunocompromised host. Production of proinflammatory cytokines, such as interleukin-6 (IL-6) and IL-8, by host cells in response to Candida albicans can be expected to have a major impact in the activation of immune effector cells against the invading microorganism. Using a human cell--C. albicans coculture model system, we determined that this microorganism can trigger secretion of these potent chemoattractant and proinflammatory cytokines by oral mucosal fibroblasts. This response varied depending on the infecting strain and required fungal viability, germination of yeast into hyphae and mannose-mediated direct contact between the host cell and Candida. The secretion of proinflammatory cytokines by oral mucosal fibroblasts in response to C. albicans suggests that these cells have the potential to enhance the host defense against this organism in vivo. This may have important implications in controlling fungal overgrowth in the oral cavity.

Candida albicans↗

PubMed1991

Reduced bactericidal activity in neutrophils from scorbutic animals and the effect of ascorbic acid on these target bacteria in vivo and in vitro.

Actinomycetes, involved in oral and periodontal diseases, cause serious infections in immunocompromised hosts. Severely scorbutic guinea pig leukocytes killed only 12% of phagocytosed actinomycetes, had distorted nuclear morphology, had 16 times less ascorbate, and had no chemotactic responses in vitro. Ascorbate reversed these indices and also prevented nitrosamine formation by oral organisms. Degranulating leukocytes release lactoferrin and ascorbate that chelate iron, essential for microorganisms. Ascorbic acid, 2,2'-bipyridine and 1,10-phenanthroline were bactericidal to several bacterial pathogens at millimolar concentrations. Iron alone reversed this effect. In in vivo experiments an Actinomyces viscosus monoflora was implanted in rhesus monkeys. Plaque and serum samples showed decreased (by six orders of magnitude) bacterial counts and decreased actinomycete antibody titers in animals given 1 g ascorbate/d. Removing ascorbate returned counts and titers to preascorbate concentrations. Fifteen marmosets, receiving twice daily topical applications of ascorbate or water, had comparatively lower gingival, calculus, and plaque indices and only slightly lowered actinomycete counts.

Actinomyces viscosus↗

PubMed1993

Increased adherence of Staphylococcus aureus from cystic fibrosis lungs to airway epithelial cells.

Airway colonization by Staphylococcus aureus is a frequent feature of cystic fibrosis (CF). To assess the pathogenesis of selective colonization with this organism, we compared the capacity of S. aureus isolated from the respiratory tract of CF and non-CF patients to adhere to epithelial cells from the upper and lower airways of CF and control subjects. Bacterial adherence to bronchial epithelial cell lines was significantly greater for CF than for non-CF isolates (p < 0.001). Of 17 CF S. aureus isolates 12 adhered at a level > 1 bacterium per cell; this was true for only 1 of 14 non-CF isolates. CF S. aureus isolates also bound more avidly than non-CF isolates to ciliated (p < 0.05) and squamous nasal cells (p < 0.02) and buccal epithelial cells (p < 0.005) freshly harvested by scraping. Each S. aureus isolate bound with equal avidity to epithelial cells from CF patients and healthy individuals. Adherence was not related to sex, age, severity of pulmonary disease, presence of other microorganisms in the airways, or genotype of the CF hosts. Binding of S. aureus was blocked by proteinase treatment of organisms, suggesting that adherence is mediated by one or more peptide adhesins. We propose that the high prevalence of adherent S. aureus is due either to selection of adherent strains by CF airways or to induction of an adherent phenotype by factors residing at the CF airways surface.

Adolescent↗

PubMed1980

Uptake and retention of tin by S. mutans.

The uptake of tin by S. mutans from stannous fluoride or stannous chloride solutions was determined by atomic absorption spectroscopy. The uptake occurred rapidly, and the microorganism was shown to have a greater capacity and higher affinity to uptake of tin than of other metal ions tested. In 10 mM solutions, bound tin amounted to 17.5 per cent of the cellular dry mass. The tin uptake was independent of cell metabolism. The cell bound tin could not be washed out with water or saline, but 84 per cent was removed by ethylenediaminetetraacetic acid solutions. When pH was lowered by low 2, increasing loss of bound tin occurred. It is suggested that the binding occurs to polyanionic structural polymers in the cell wall and the cell capsule.

Binding, Competitive↗