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A polyurethane elastomer was microbiologically evaluated in vitro for its potential use in resilient denture liners. Specimens were immersed in suspensions of ten selected oral microorganisms; this was followed by viable cell counts at intervals during a 16-week period. Results indicated that the polyurethane neither supported the growth of the organisms nor was it degraded.
Antibiotic and disinfectant sensitivities of opportunistic bacteria, isolated from the oral cavity of normal subjects and orthodontic patients, were under study. The findings evidence that oral microflora of patients with orthodontic conditions is more rich in microorganisms that can induce pyoinflammatory diseases than that in health. Among the isolated opportunistic bacteria strains were found that were resistant to both: antibiotics and disinfectants. Antibiotic sensitivities of the microorganisms isolated from normal subjects and patients were found virtually the same, whereas the strains isolated from the patients have shown a higher sensitivity to disinfectants. The authors emphasize that effective prevention of pyoseptic complications in the maxillofacial area involves not only bacteriologic monitoring and studies of the microorganism sensitivity to antibiotics, but analysis of the bacterial sensitivity to disinfectants as well.
The pH-decrease in dental plaque in vivo after mouth rinses with solutions of sucrose and maltose has been compared. No statistically significant differences were found between the results obtained with these two disaccharides. Pooled samples of parotid saliva, centrifuged whole saliva and dental plaque supernatants were separated with the isoelectric focusing technique. The results suggest that maltose is hydrolysed in parotid saliva by the salivary alpha-amylase and in dental plaque by enzymes from sources other than the salivary glands, probably microorganisms. No bacterial alpha-amylases, separated from salivary alpha-amylase, were found in whole saliva specimens or in dental plaque supernatants. Quantitative determinations of "maltase" and amylase activities in parotid saliva, centrifuged whole saliva and dental plaque supernatants from 10 subjects were carried out. The highest enzyme activity of "maltase" was found in the samples of dental plaque and the highest amylase activity in parotid saliva specimens.
We studied the effects of polyphenol oxidase and asparaginase on microorganism adhesion to buccal epithelial cells. These enzymes reduced adhesion of pathogenic microorganisms (uropathogenic and Escherichia coli, Salmonella enteritidis, Entamoeba spp., Influenza virus, Candida albicans, Streptococcus spp.) and had virtually no effect on adhesive characteristics of probiotic variants of Escherichia coli and Lactobacillus fermentum.
10 specimens taken from oral hairy leukoplakia were compared to 8 histological preparations from hairy tongue. We found 9 criteria helpful concerning the histopathologic differential diagnosis of these entities. Oral hairy leukoplakia shows a gently papillated surface, a prominent horny layer with confluent bacterial overgrowth, and ballooned epithelial cells with a distinct perinuclear halo in a bandlike arrangement. Hairy tongue, in contrast, grows exophytically with a digitiform surface, the horny layer is rather thin, and the microorganisms are confined to the ends of the digitations; the ballooned epithelial cells show pale cytoplasm. Considering the growing incidents of HIV infection, the dermatologist should be familiar with the characteristics of oral hairy leukoplakia and its histopathological differential diagnosis.
Ten patients undergoing treatment with bridges supported by osseo-integrated oral titanium implants were studied regarding the oral microflora. Saliva samples for microbiological studies were collected before the abutment operation, 1 week after the operation, after the bridges were inserted and again 52 weeks after the abutment operation. The implants did not induce colonization with "plaque streptococci" such as Streptococcus mutans and Streptococcus sanguis. A marked colonization with potentially pathogenic microorganisms such as Staphylococcus aureus, Pseudomonas species and enterobacteria was observed after the abutment operation. This was probably due to the use of surgical dressing.
BACKGROUND: Because of the growing concern of the infectious nature of aerosols produced by air polishers, the Centers for Disease Control and Prevention and the American Dental Association have made recommendations to minimize dental aerosols. In addition, a device was developed in 1997 to reduce the aerosol generated during air polishing. METHODS: The authors conducted a blinded clinical study to determine the effectiveness of an aerosol reduction device during air polishing. All 30 subjects underwent two minutes of air polishing, one with the aerosol reduction device on one side of the mouth and one without the device on the opposite side. Microbial samples were collected on blood agar plates positioned 12 inches from the subject's mouth and from one plate attached to the dental hygienist's face mask. The sample plates were then inverted and incubated for three days at 37 C. RESULTS: Using the paired t-test, the authors found that the air polisher without the aerosol reduction device generated a significantly greater mean quantity of colony-forming units, or CFUs, 12 inches from the subject's mouth (mean +/- standard deviation, 148.00 +/- 145.00 CFUs) than the air polisher with the aerosol reduction device (20.10 +/- 53.90 CFUs) (P < .0001). In addition, the air polisher without the aerosol reduction device generated a significantly greater number of CFUs on the face mask plate (40.90 +/- 33.80 CFUs) than the air polisher with the aerosol reduction device (8.80 +/- 15.10 CFUs) (P < .0001). CONCLUSION: The data suggest that the aerosol reduction device is effective in reducing the number of microorganisms generated during air polishing. CLINICAL IMPLICATIONS: Air polishing with the aerosol reduction device may decrease the potential for disease transmission.
Over the last 10-15 yr antibiotic resistance has increased in the oral microflora. The beta-lactam antibiotics, i.e., penicillins and cephalosporins, are the most frequently used antimicrobial agents. Unfortunately, the efficiency of these drugs is increasingly being challenged by the emergence of resistant bacteria, which is mainly due to their production of beta-lactamases. In this paper, mechanisms of antibiotic resistance are reviewed, with emphasis on beta-lactamases. This review also discusses how the presence of beta-lactamases in oral microorganisms may affect the treatment of oral diseases. Dentists can influence the emerging global crisis of antibiotic resistance by carefully evaluating the indications for antibiotic treatment. General guidelines for when and how to use antibiotics in dentistry are reviewed.
beta-Defensins are cationic peptides with broad-spectrum antimicrobial activity that are produced by epithelia at mucosal surfaces. Two human beta-defensins, HBD-1 and HBD-2, were discovered in 1995 and 1997, respectively. However, little is known about the expression of HBD-1 or HBD-2 in tissues of the oral cavity and whether these proteins are secreted. In this study, we characterized the expression of HBD-1 and HBD-2 mRNAs within the major salivary glands, tongue, gingiva, and buccal mucosa and detected beta-defensin peptides in salivary secretions. Defensin mRNA expression was quantitated by RNase protection assays. HBD-1 mRNA expression was detected in the gingiva, parotid gland, buccal mucosa, and tongue. Expression of HBD-2 mRNA was detected only in the gingival mucosa and was most abundant in tissues with associated inflammation. To test whether beta-defensin expression was inducible, gingival keratinocyte cell cultures were treated with interleukin-1beta (IL-1beta) or bacterial lipopolysaccharide (LPS) for 24 h. HBD-2 expression increased approximately 16-fold with IL-1beta treatment and approximately 5-fold in the presence of LPS. Western immunoblotting, liquid chromatography, and mass spectrometry were used to identify the HBD-1 and HBD-2 peptides in human saliva. Human beta-defensins are expressed in oral tissues, and the proteins are secreted in saliva; HBD-1 expression was constitutive, while HBD-2 expression was induced by IL-1beta and LPS. Human beta-defensins may play an important role in the innate defenses against oral microorganisms.
The subject of this study was investigation of quantitative relations between streptococci, lactic acid bacilli and actinomycetes and staphylococci present in the oral cavity. It was found that in each tested sample of saliva streptococci are present which inhibit growth of an indicator strain Staphylococcus aureus 209P. Percentage of such streptococci varies from 11.1% to 100% (mean value 52.9 +/- 19.7%). There is a negative correlation between number of streptococci and staphylococci in samples of saliva delivered from the same oral cavity. Pearson's linear correlation coefficient was r = -0.7962 (p < 0.0001), and Spearman's correlation rank was rs = -0.7667 (p < 0.0001). Lactic acid bacilli were inhibiting growth of staphylococci only in conditions in which there were not neutralized by organic acids produced by these microorganisms. Actinomycetes had no influence at all on growth of these microorganisms. These results suggest that streptococci are responsible for antagonistic properties of oral cavity bacterial flora in relation to staphylococci. Numbers of streptococci conditions size of staphylococcal population in this environment. Staphylococci practically exert no antagonistic activity against cohabiting with them streptococci.
Dental plaque is composed of a biofilm community of microorganisms on teeth that coats the oral cavity, including attaching to the teeth, and provides a protective reservoir for oral microbial pathogens, which are the primary cause of persistent and chronic infectious diseases. Oral streptococci are pioneering organisms that play an important role in biofilm formation on tooth surfaces as well as being primary causative agents of dental caries. The purpose of this study was to clarify the role of the E2f1 gene in susceptibility to dry mouth and bacterial adherence of oral streptococci to tooth surfaces in animal model experiments. A mutation of the E2f1 gene in mice is known to cause enhanced T-lymphocyte proliferation, leading to testicular atrophy, splenomegaly, salivary gland dysplasia, and other systemic and organ-specific autoimmunity. We found a decreased volume of saliva production and protein production rate, along with increased amylase activity, IgA concentration, and mucin 1 concentration in E2F-1(-/-) mice as compared with the control C57BL/6 mice. Further, we quantified the recolonization of oral streptococci in E2F-1(-/-) mice and found that a higher number of some oral streptococci were colonized on the teeth of these mice. In particular, following oral ingestion of 1% sucrose in water, the colonization of Streptococcus mutans increased in comparison with other streptococci. Our results suggest that the E2f1 gene may affect susceptibility for oral biofilm formation by streptococci in humans with dry mouth.
Adhesion of microorganisms to various mucosal surfaces appears to be essential for initiating infection. The role of adhesion to host surfaces in pathogenesis of human mycoses, particularly the various manifestations of candidiasis, has been shown experimentally and correlated with epidemiological data.
The aim of this study was to investigate the influence of large doses of orally administered human IgG on the normal gastrointestinal microflora of healthy volunteers since human immunoglobulin has been tried as oral prophylaxis and therapy in gastrointestinal infections. Ten adult healthy volunteers received 10 g of IgG orally, once daily for three consecutive days. Aerobic and anaerobic microorganisms were identified in the saliva and stool specimens, using morphological, biochemical and serological tests and gas-liquid chromatography. Although the immunoglobulin preparation contains antibodies against a variety of microorganisms, there were no significant changes in the numbers of different aerobic and anaerobic microorganisms due to the oral intake of the immunoglobulin. IgG may, therefore, be used against pathogens without disturbing the normal oral and intestinal microflora.
Mononuclear cell preparations isolated by Ficoll-Hypaque centrifugation from human peripheral blood were found to vary considerably in the number of monocytes they contained (mean, 20.3%; range, 13 to 33%). The regulatory role of monocytes in T cell proliferative responses to sonic extracts of a panel of oral microorganisms was therefore investigated. T cells were fractionated by anti-immunoglobulin chromatography and depleted of monocytes by treatment with a monoclonal anti-human Ia-like (DR locus antigen) antibody and complement. Purified populations of monocytes were obtained by extensive adherence procedures. The resultant cell populations were greater than 95% pure, as judged by indirect immunofluorescence on a fluorescence-activated cell sorter. Monocyte-depleted T cells failed to respond by proliferation to the nonoral antigen tetanus toxoid, as well as to any oral microorganism, but retained responsiveness to phytohemagglutinin. Readdition of monocytes in final concentrations of from 5 to 15% resulted in the restoration of maximal T cell proliferation. Monocytes in greater numbers suppressed T cell responses to all sonic extracts tested.
BACKGROUND: Behçet's disease is a multisystem disorder of unknown etiology, affecting predominantly the oral mucosa, skin, and eyes. Recurrent and painful episodes of oral ulcerations interfere with regular oral hygiene leading to rapid bacterial plaque accumulation. The aims of this study were to evaluate the periodontal status of patients with Behçet's disease and determine serum antibody responses to selected oral microorganisms, including major periodontopathogens in these patients. METHODS: Thirty-three patients with Behçet's disease and 15 healthy subjects were included in the study. Plaque, sulcular bleeding, periodontal index scores, probing depths, and total number of teeth were recorded. Serum IgG antibody levels to a panel of 13 oral microorganisms were determined. RESULTS: Significantly higher values for each of the clinical measures were observed in patients with Behçet's disease compared to healthy subjects (P <0.0001). Antibody levels to selected members of plaque, including Actinomyces viscosus, Streptococcus mutans, Streptococcus sanguis, Streptococcus oralis, Eikenella corrodens, Campylobacter rectus, and Prevotella intermedia were significantly lower in patients with Behçet's disease than in controls (P <0.001-0.05). In contrast, these patients exhibited significantly elevated antibody levels to Actinobacillus actinomycetemcomitans Y4 compared to controls (P <0.01). CONCLUSIONS: Our data indicate that the patients with Behçet's disease generally exhibit clinical findings of established periodontal disease. Decreased antibody responses to early colonizers of both supra- and subgingival plaque were observed along with the elevation in antibody levels to A. actinomycetemcomitans. These results suggest that the bacterial plaque ecology and/or immune responses to these microorganisms may be affected in Behçet's disease which could lead to changes in the expression of periodontal disease.
In this study, we investigated the oral status of children suffering from end-stage renal disease (ESRD) with the aim of determining the causes of low caries prevalence in this population (using the CRT bacteria and buffer test), and compared results with a control group (n=38). In the study group, there were 38 children (aged 4-17 years) who were being treated in pediatric nephrology units at three different hospitals in Izmir, Turkey. The study and control groups did not significantly differ in daily tooth brushing frequency and periodic dental check-up frequency. Severe enamel hypoplasia was present in the study group. Dmft, DMFT, gingival and plaque indices were compared statistically in mixed dentition stage with the control group and dmft and gingival status showed a statistically significant difference (p<0.05). The differences among groups for DMFT and plaque indices were not statistically significant. In the study group, high salivary buffer capacity was found in 89.5% of patients. Salivary levels of cariogenic streptococcus mutans and lactobacilli in the study group were significantly lower than in the control group. In conclusion, probably due to increased concentrations of antibacterial chemicals such as urea in the saliva of children with ESRD, decreased levels of cariogenic microorganisms were detected. Therefore, although dental treatment need is not high, these children should receive dental health education, including oral hygiene instruction, in order to improve their overall oral health.
The possible link between oral and general health is based on an old concept. This paper summarizes current ideas on the role of translocation of oral pathogens to other parts of the body in the development of systemic disease. It appears that colonisation of the oral cavity by respiratory pathogens is a risk factor in the development of pneumonia in institutionalised elderly and intensive care patients. Using a chloorhexidine oral rinse may reduce the risk of pneumonia. Furthermore, periodontal disease is associated with an increased risk of cardiovascular disease. Translocation of oral microorganisms and an increase in serum concentrations of inflammatory mediators are considered to play a role in the development of cardiovascular disease. Potentially, preventive oral health care and periodontal intervention could play a part in preventing cardiovascular disease.
OBJECTIVES: To compare the clinical effects of a fluoride-containing varnish (Fluor-Protector) in combination with a chlorhexidine-containing varnish (Cervitec) on existing root caries lesions in a group of frail elderly subjects. METHODS: A randomised double blind longitudinal study was utilised. Subjects (n = 102) were randomly allocated to a Test or Placebo group. All leathery and soft root caries lesions in all subjects were coated with Fluor-Protector while the lesions in the Test group were also coated with Cervitec and the lesions in the Placebo group were coated with a Placebo varnish. Treatments were repeated five times in a 12-month period. Clinical parameters associated with root caries, measurements of individual lesions and salivary levels of caries associated bacteria were made at intervals. RESULTS: The clinical severity of the lesions in the Test group did not change significantly during the 12-month study period. In the Placebo group the mean lesion width and lesion height and length of exposed root increased significantly and the lesions were significantly closer to the gingival margin. There were no significant changes in the salivary levels of caries-associated microorganisms after 12 months although, in both groups, there was initially a significant reduction in the salivary levels of mutans streptococci. CONCLUSIONS: The combination of Fluor-Protector and Cervitec is a useful, simple, quick and non-invasive method for the control and management of existing root caries lesions. The procedure could be performed by a dental hygienist and may be usefully applied in other high-risk groups including persons with Parkinson's disease, debilitating neuromuscular conditions and dry mouth from whatever cause.