Biomedical subjects

Lakshman P Samaranayake

Publications and source records attributed to Lakshman P Samaranayake.

At least 19 recordsLinked to original sources

PubMed2006

Hyphal invasion of Candida albicans inhibits the expression of human beta-defensins in experimental oral candidiasis.

Oral epithelium reacts to microbial challenges by eliciting a defensive response that includes the production of antimicrobial peptides. This study investigated the expression of human beta-defensins-1, 2, and 3 in reconstituted human oral epithelia during experimental oral infections with six different Candida species, and a wild-type C. albicans isolate and five of its mutants. The expression of defensins was induced after 12 hours infection with the wild-type C. albicans, but this response was not seen for the noninvasive hyphal mutants nor the secreted aspartyl proteinase mutants. Furthermore, defensin expression was not detected after 48 hours in epithelia infected with either C. albicans wild-type isolate or its invasive hyphal and proteinase mutants. Most of the non-albicans Candida were capable of inducing the expression of defensins in epithelia after 24 or 48 hours of infection. These Candida-host interaction patterns suggest that the oral epithelia possess mechanisms for sensing the early invasion of C. albicans through recognition of the presence of hyphae and proteinases of Candida and respond to the insult by producing antimicrobial peptides. This hyphal-invasion-dependent inhibition of defensin expression in oral epithelium that undermines the host surveillance system represents a hitherto undescribed novel pathogenic mechanism of C. albicans.

Aspartic Acid Endopeptidases↗

PubMed2006

Effect of oral bacteria on growth and survival of Candida albicans biofilms.

The purpose of this study was to evaluate the effect of eight aerobic and anaerobic oral commensal bacterial species on in vitro Candida albicans biofilm development. A single isolate of C. albicans 2560 g, and eight different species of oral bacteria comprising, Actinomyces israelii, Lactobacillus acidophilus, Prevotella nigrescens, Porphyromonas gingivalis, Pseudomonas aeruginosa, Escherichia coli, Streptococcus mutans, and Streptococcus intermedius were studied using an in vitro biofilm assay. Biofilm formation was quantified in terms of the ability of Candida to grow on polystyrene plastic surfaces co-cultured with the foregoing bacteria. A viable cell count was used to quantify the sessile yeast growth and scanning electron microscopy was employed to confirm and visualize biofilm formation. Co-culture with differing concentrations of bacteria had variable effects on Candida biofilm formation. Co-culture with the highest concentrations of each of the foregoing bacteria resulted in a consistent reduction in the yeast counts in the candidal biofilm (P<0.05), except for L. acidophilus, S. mutans, and, S. intermedius co-cultures. Further, on regression analysis a significant negative correlation between the co-culture concentration of either P. gingivalis or E. coli and viable yeast counts in the biofilm was noted (P<0.05) although this was not evident for the other bacterial species. Taken together, our data indicate that, quantitative and qualitative nature of the bacteria modulate C. albicans biofilm formation in mixed species environments such as the oral cavity.

Bacteria, Aerobic↗

PubMed2006

Identification of cultivable microorganisms from root canals with apical periodontitis following two-visit endodontic treatment with antibiotics/steroid or calcium hydroxide dressings.

The study was aimed at comparing the efficacy of disinfection of root canals with periapical radiolucencies when treated with either antibiotics/steroid medicaments (Ledermix or Septomixine) or a calcium hydroxide paste (Calasept). Microbiological samples were taken before and after two-visit endodontic treatment from 88 canals with apical periodontitis. All of the canals but one (87 of 88) had cultivable growth before treatment. After dressing with Ledermix, Septomixine, or Calasept, the percentages of canals remained with positive growth were 48% (13 of 27), 31% (8 of 26), and 31% (11 of 35), respectively. The chi(2) tests showed there were no significant differences in the number of canals with positive growth or mean colony forming units counts after instrumentation, irrigation and dressing. In the Ledermix group, 38 strains of bacteria were recovered. The Septomixine group had 25 strains, and the Calasept group had 25 strains. Gram-positive facultative anaerobic cocci (including staphylococci and streptococci) were more prevalent than the Gram-negative obligate anaerobic rods after treatment in all three groups. Similarities in the reduced number of canals with residual growth, and the prevalence of Gram-positive facultative anaerobic cocci suggest that the use of different inter-appointment dressings produced similar microbiological outcomes. However, factors other than the antimicrobial effectiveness of intracanal medicaments may also be responsible for the results observed.

Anti-Bacterial Agents↗

PubMed2006

Application of an interactive computer program to manage a problem-based dental curriculum.

Managing the change from traditional to problem-based learning (PBL) curricula is complex because PBL employs problem cases as the vehicle for learning. Each problem case covers a wide range of different learning issues across many disciplines and is coordinated by different facilitators drawn from the school's multidisciplinary pool. The objective of this project was to adapt an interactive computer program to manage a problem-based dental curriculum. Through application of a commercial database software--CATs (Curriculum Analysis Tools)--an electronic database for all modules of a five-year problem-based program was developed. This involved inputting basic information on each problem case relating to competencies covered, key words (learning objectives), participating faculty, independent study, and homework assignments, as well as inputting information on contact hours. General reports were generated to provide an overview of the curriculum. In addition, competency, key word, manpower, and clock-hour reports at three levels (individual PBL course component, yearly, and the entire curriculum) were produced. Implications and uses of such reports are discussed. The adaptation of electronic technology for managing dental curricula for use in a PBL curriculum has implications for all those involved in managing new-style PBL dental curricula and those who have concerns about managing the PBL process.

Curriculum↗

PubMed2005

Frequent allelic loss of 21q11.1 approximately q21.1 region in advanced stage oral squamous cell carcinoma.

A fine mapping of loss of heterozygosity (LOH) was performed in oral squamous cell carcinoma (OSCC), using 12 markers on 21q11.1 approximately q21.1. We studied 43 resected primary invasive tumors and their paired normal tissues, concurrent dysplasia or carcinoma in situ in separate areas from 8 of the specimens, and 6 local recurrent carcinomas. LOH status was compared between lesions of different phases of progression within the same patient. A high frequency of LOH was observed for D21S1410, D21S120, and D21S1433 (60% each) in the primary lesions, constituting two interstitial deleted regions encompassing eight known genes. Cases showing LOH of D21S120 were significantly associated with advanced clinical stages (III and IV; P=0.02). Consistent allelic loss was observed in 64.2% of the informative cases between the precursor lesions and their corresponding invasive tumors, and in 59.5% of those between the primary lesions and their recurrent counterparts. Fewer than half of the different lesions within a given patient showed discordant allelic loss for tested markers. Our results suggest that 21q11.1 approximately q21.1 harbors tumor suppressor genes in OSCC. Genetic divergence may develop during tumor clone evolution.

Carcinoma in Situ↗

PubMed2005

Identification of cultivable microorganisms from primary endodontic infections with exposed and unexposed pulp space.

This study was aimed at comparing the cultivable microorganisms in canals with periapical radiolucencies with exposed and unexposed pulp space. Microbiological samples were taken and analyzed from 45 canals with exposed pulp space, and 43 canals with unexposed pulp space. The canal contents were analyzed by aerobic/anaerobic culture, and conventional identification techniques. There were 211 isolates of bacteria belonging to 28 genera and 55 species recovered from exposed canals. In the unexposed group, 185 isolates of bacteria were recovered, of which 54 species of 28 genera were identified. Among the four most common genera, Prevotella was significantly more common in the exposed group (51/211 in the exposed group versus 30/185 in the unexposed group) (p = 0.049), while there were no differences in prevalence of Actinomyces, Peptostreptococcus, and Campylobacter between two groups of canals. In addition, Fusobacterium nucleatum and Propionibacterium acne were significantly more common in the unexposed canals (p = 0.047 and p = 0.0051, respectively). Similarity in bacterial species in these two groups suggests that pulp space exposure may not be a significant factor in determining the type of bacteria present in infected canals.

Adolescent↗

PubMed2005

Expression of human beta-defensin-3 in gingival epithelia.

OBJECTIVE: This study aimed to investigate the expression patterns of the newly discovered human beta-defensin-3 (hBD-3) in human gingiva. BACKGROUND: Human beta-defensins (hBDs) are a group of small, broad-spectrum, cationic antimicrobial peptides. Our recent study showed that the expression levels of hBD-1 and 2 peptides were associated with periodontal conditions. METHODS: A total of 49 gingival biopsies were collected, including 33 samples from 21 patients with chronic periodontitis and 16 samples from 16 periodontally healthy subjects. The expression of hBD-3 was detected by immunohistochemistry and in situ hybridization. Double staining was undertaken to identify hBD-3 peptide-positive cells, using CD-1a and cytokeratin 20 as markers for Langerhans cells and Merkel cells, respectively. RESULTS: hBD-3 peptide was detected in 88% of the samples, which was confined to the gingival epithelia. In healthy control subjects, hBD-3 peptide was more frequently detected in the basal layer as compared to the patients (53% vs. 18%, p < 0.05). In patients, hBD-3 expression extended from the basal layer to the spinous layers (82%), in which hBD-3 was confined to the basal and deep spinous layers in clinically healthy tissues from patients, whereas it extended to the superficial spinous layers in pocket tissues from patients (0% vs. 50%, p < 0.05). In both groups, hBD-3 peptide was expressed not only in gingival keratinocytes, but also in Langerhans cells and Merkel cells. hBD-3 transcripts were detected in 90% of the samples and they were confined to the basal and/or suprabasal layers of gingival epithelia. CONCLUSIONS: This study shows that hBD-3 is frequently expressed in gingival epithelia. The appropriate expression of hBD-3 peptide may contribute to the maintenance of periodontal homeostasis, possibly through its antimicrobial effect and promotion of adaptive immune responses.

Adolescent↗

PubMed2004

Direct detection of cell surface interactive forces of sessile, fimbriated and non-fimbriated Actinomyces spp. using atomic force microscopy.

Actinomyces species are predominant early colonizers of the oral cavity and prime mediators of inter-bacterial adhesion and coaggregation. Previous workers have evaluated the adhesion of Actinomyces spp. by quantitative assessment of sessile, as opposed to planktonic cells attached to substrates, but did not quantify the cell surface interactive forces. Therefore we used atomic force microscopy to directly detect the interactive force between an approaching silicon tip and sessile Actinomyces spp. adhering to a substrate, at nanonewton (nN) range force levels. A total of eight strains each belonging to fimbriated and non-fimbriated Actinomyces species were employed, namely A. bovis, A. gerencseriae, A. israelii, A. meyeri, A. naeslundii genospecies 1 and 2, A. odontolyticus and A. viscosus. The sterile mica discs, used as the adhesion substrate, were immersed in mono-species bacterial suspensions for five days to obtain a thin bacterial biofilm. Interactive forces were measured using a silicon nitride cantilever attached to a Nanoscope IIIA atomic force microscope. The interactive forces between the approaching silicon nitride tip and bacterial biofilm surfaces were randomly quantified at three different locations on each cell; namely, the cell surface proper, the periphery of the cell and the substrate and, the interface between two cells. When the interactive forces at these locations of the same species were compared, significantly higher force levels at the cell-cell interface than the other two locations were noted with A. gerencseriae (P < 0.001), A. viscosus (P < 0.01) and A. israelii (P < 0.05). When the interactive forces of different Actinomyces spp. at an identical location were compared, fimbriated A. naeslundii genospecies 2 showed the greatest interactive force at the cell surface proper (-32.6 +/- 8.7 nN, P < 0.01). A. naeslundii genospecies 1, 2 and A. viscosus demonstrated greater interactive force at the cell-mica periphery than the other five species (P < 0.05); A. viscosus (-34.6 +/- 10.5 nN) displayed greater interactive force at the cell-cell interface than the others (P < 0.01), except for A. gerencseriae (P > 0.05). These data indicate that fimbriated Actinomyces spp., including A. naeslundii genospecies 1, 2 and A. viscosus exert higher cell surface interactive forces than those devoid of fimbriae and, such variable force levels may modulate their adhesion and coaggregation during biofilm formation.

Actinomyces↗

PubMed2004

Biofilm formation of Candida albicans is variably affected by saliva and dietary sugars.

The pathogenesis of both superficial and systemic candidiasis is closely dictated by properties of the yeast biofilms. Despite extensive investigations on bacterial biofilms, the characteristics of candidal biofilms, and various factors affecting this process remain to be determined. Therefore we examined the effect of human whole saliva and dietary sugars, glucose and galactose on the adhesion and biofilm formation of Candida albicans. Biofilms of C. albicans isolate 192 887 g were developed on polystyrene, flat-bottomed 96-well microtiter plates and monitored using ATP bioluminescence and tetrazolium (XTT) reduction assays as well as the conventional colony forming unit (CFU) evaluation. Our data showed that both the ATP and the XTT assays strongly correlated with the CFU assay (ATP versus CFU: r = 0.994, P = 0.006; XTT versus CFU: r = 0.985, P = 0.015). Compared with a glucose-supplemented (100 mM) medium, galactose containing (500 mM) medium generated consistently lower levels of both candidal adhesion and biofilm formation (all P < 0.05), but a higher pace of biofilm development over time (96 h). Whist the presence of an immobilised saliva coating had little effect on either the candidal adhesion or biofilm formation, the addition of saliva to the incubation medium quantitatively affected biofilm formation especially on day 3 and 4, without any significant effect on yeast adhesion. To conclude, biofilm formation of C. albicans within the oral milieu appears to be modulated to varying extents by dietary and salivary factors and, further investigations are required to elucidate these complex interactions.

Adenosine Triphosphate↗

PubMed2004

In vitro growth, acidogenicity and cariogenicity of predominant human root caries flora.

Streptococcus mutans (Sm), Lactobacillus acidophilus (La) and Actinomyces israelii (Ai) have been associated with root surface caries, which is an increasing problem in elderly Chinese. The aim of this study therefore, was to evaluate in vitro, the growth, acidogenicity and cariogenicity of these organisms, both in mono- and co-cultures using an in vitro model. Forty-eight root specimens were prepared using intact extracted human molars. Fresh, wild-type bacteria obtained from root caries lesions were assembled into seven experimental groups as either mono- or co-cultures and incubated with the root specimens. Appropriate controls were included. Growth curve of each experimental group was monitored for 24h, aerobically, at 37 degrees C using a microplate reader. The pH of the medium was recorded after 24-h incubation using a pH meter. Mean depths of artificial root lesions produced in each cultural group were measured using polarized light microscopy in specimens cut into thin sections (100+/-20 microm). Compared with mono-cultures, synergistic growth was observed in co-cultures of 'La+Sm', 'Ai+La' and 'Ai+La+Sm'. Mean lesion depth produced in La group was significantly shallower than other mono- or co-culture groups (p<0.01). The pH values of all culture media were similar after 24-h incubation. The current data elucidate the complex interactions of three predominant bacterial species considered prime agents of human root surface caries.

Acids↗

PubMed2004

Cytotoxic drugs, radiotherapy and oral candidiasis.

The increased incidence of oral candidiasis in patients with malignancies stems partly from the systemic disease itself and, partly from the therapeutic measures such as cytotoxic and other immunosuppressive drugs and radiotherapy they receive during management of such malignancies. In this review we discuss the clinical and laboratory findings on the relationship between cytotoxics, radiotherapy and oral candidiasis, possible mechanisms of pathogenicity following such therapy, as well as precautions that could be taken to minimize such recalcitrant yeast infections.

Antineoplastic Agents↗

PubMed2004

The effect of antiretroviral therapy on the prevalence of HIV-associated oral candidiasis in a Spanish cohort.

OBJECTIVE: To investigate the temporal changes in the prevalence of oral candidiasis in a cohort of Spanish human immunodeficiency virus (HIV)-infected individuals, before and after the introduction of highly active antiretroviral therapy (HAART). STUDY DESIGN: Retrospective analysis of a clinical database from "Carlos Haya" Hospital, Málaga, Spain, from 1995 to 2000. The prevalence of oral candidiasis was assessed in 807 HIV/AIDS patients and the temporal progression of its major variants evaluated using a linear regression model. RESULTS: Overall oral candidiasis was prevalent in 30.0% to 48.3% of the cohort throughout and no significant variation in its incidence was noted during the study period. Prevalence of erythematous candidiasis increased from 24.5% (1995) to 45.0% (2000) and pseudomembranous candidiasis decreased from 22.4% (1995) to 5.2% (2000) (P<.05). Hyperplastic candidiasis was not detected in the cohort after the introduction of HAART therapy. CONCLUSIONS: Although oral candidiasis in HIV-infected Spanish individuals has not decreased significantly after the introduction of HAART, there appears to be a significant reduction in hyperplastic and pseudomembranous variants of the disease with a compensatory increase in erythematous candidiasis.

AIDS-Related Opportunistic Infections↗

PubMed2004

Expression of human beta-defensins-1 and -2 peptides in unresolved chronic periodontitis.

BACKGROUND: Human beta-defensins (hBDs) are antimicrobial peptides which contribute to host innate immunity by disrupting the membrane integrity of a broad spectrum of microorganisms. OBJECTIVES: This study aimed to determine the expression profiles of hBD-1 and -2 peptides in gingiva and to assess the possible relations of these antimicrobial peptides with periodontal health and disease. METHODS: Seven periodontally healthy subjects and 22 patients with unresolved chronic periodontitis were recruited and the gingival biopsies collected consisted of healthy tissues from the healthy subjects (HT-C); periodontal pocket tissues (PoT) and inflamed connective tissues (ICT) from the base of pocket, i.e. granulation tissues, as well as clinically healthy tissues (HT-P) from the adjacent clinically healthy sites from the patients. The expression of hBD-1 and -2 peptides was detected by immunohistochemistry and quantitatively analyzed with a computerized image processing system. RESULTS: Both hBD-1 and -2 peptides were detected in all periodontally healthy subjects, while hBD-1 was detected in all patients and hBD-2 was found in most of the patients. Their expression was mainly confined to the granular and spinous layers of gingival epithelium, in which hBD-1 was detected in both intercellular spaces and cytoplasm, whereas hBD-2 was mainly observed in the cytoplasm. HT-C expressed significantly higher levels of hBD-2 than HT-P (p < 0.05). Within the patients, both defensins were up-regulated significantly in PoT as compared with the adjacent HT-P (p < 0.05). CONCLUSIONS: The present study showed that hBD-1 and -2 were frequently expressed in the granular and spinous layers of gingival epithelia and their expression may be associated with periodontal health and disease.

Anti-Infective Agents↗

PubMed2004

Topical and systemic antibiotics in the management of periodontal diseases.

Both systemic and topical antibiotics are increasingly used in the management of periodontal infections. Whilst these drugs are used mostly on an empirical basis, some contend that rational use of antibiotics should be the norm due to their wide abuse and consequential global emergence of antibiotic resistance organisms. Here we review the rationale and principles of antimicrobial therapy, treatment goals, drug delivery routes and various antibiotics that are used in the management of periodontal diseases. The pros and cons of systemic and local antibiotic therapy are described together with practical guidelines for their delivery. The available data indicate, in general, that mechanical periodontal treatment alone is adequate to ameliorate or resolve the clinical condition in most cases, but adjunctive antimicrobial agents, delivered either locally or systemically, can enhance the effect of therapy in specific situations. This is particularly true for aggressive (early onset) periodontitis, in patients with generalised systemic disease that may affect host resistance and in case of poor response to conventional mechanical therapy. Locally delivered antibiotics together with mechanical debridement are indicated for non-responding sites of focal infection or in localised recurrent disease. After resolution of the periodontal infection, the patient should be placed on an individually tailored maintenance care programme. Optimal plaque control by the patient is of paramount importance for a favourable clinical and microbiological response to any form of periodontal therapy.

Actinobacillus Infections↗

PubMed2004

Severe acute respiratory syndrome and dentistry: a retrospective view.

BACKGROUND: Severe acute respiratory syndrome, or SARS, which has created panic in Asia and in some parts of North America, is the first epidemic of the new century. Although it has been well-contained, sporadic cases continue to emerge. OBJECTIVES: The authors trace the emergence of the SARS outbreak from southern China and its spread worldwide, discuss the viral etiology of the infection and its clinical features, and review the infection control guidelines issued during the outbreak by the health authorities in Hong Kong, the Centers for Disease Control and Prevention, the World Health Organization and the American Dental Association. They also review the prospects for a new outbreak and preventive measures. OVERVIEW: The disease, which is caused by a novel coronavirus termed the "SARS coronavirus," or SARS-CoV, essentially spreads through droplet infection and affects people of any age. It has a mortality rate ranging from 10 to 15 percent. A major hallmark of this disease has been the rate at which it has affected health care workers through nosocomial transmission; in some countries, up to one-fourth to one-third of those infected were in this category. However, no dental health care worker has been affected by SARS in a nosocomial or dental setting. CONCLUSIONS AND CLINICAL IMPLICATIONS: Researchers believe that a combination of factors, including the universal infection control measures that the dental community has implemented and/or the low degree of viral shedding in the prodromal phase of SARS, may have obviated the spread of the disease in dental settings. The dental community should reflect on this outbreak to reinforce the currently applied infection control measures.

Centers for Disease Control and Prevention, U.S.↗

PubMed2004

A multi-country comparison of caries-associated microflora in demographically diverse children.

OBJECTIVE: The aim of this formative international collaborative research on childhood dental caries was to undertake an initial investigation comparing the dental plaque of young children from diverse ethnic and socioeconomic backgrounds with and without dental caries. BASIC RESEARCH DESIGN: The following four null hypotheses were investigated. There were no differences in numbers of individual taxa when comparing plaque samples from: 1) caries-free children from deprived and non-deprived backgrounds; 2) children from deprived and non-deprived backgrounds with at least 3 decayed teeth; 3) children from non-deprived backgrounds who are caries free with those from similar backgrounds with at least 3 decayed teeth; and, 4) children from deprived backgrounds who are caries free with those from similar backgrounds with at least 3 decayed teeth. PARTICIPANTS: 277 children aged 3-4 years from 5 countries. MAIN OUTCOME MEASURES: A sample of interproximal plaque from anterior teeth was collected using sterile dental floss, and cultured according to accepted international standards. RESULTS: Analysis of the data found that the first null hypothesis was accepted and that the fourth was rejected. Unexpectedly, the second null hypothesis was rejected as the children with caries from deprived and non-deprived backgrounds had a different caries-associated flora. In particular, children living in deprivation harbored more caries-associated bacteria [mutans streptococci and lactobacilli]. This greater microbial challenge was associated with a higher level of cavitated carious lesions and with more frequent consumption of confectionery. Conclusions Children from deprived backgrounds with caries may be further disadvantaged by having higher levels of caries-associated microflora.

Candy↗

PubMed2004

International comparisons of health inequalities in childhood dental caries.

OBJECTIVE: To undertake formative studies investigating how the experience of dental caries in young children living in diverse settings relates to familial and cultural perceptions and beliefs, oral health-related behaviour and oral microflora. PARTICIPANTS: The scientific consortium came from 27 sites in 17 countries, each site followed a common protocol. Each aimed to recruit 100 families with children aged 3 or 4 years, half from deprived backgrounds, and within deprived and non-deprived groups, half to be "caries-free" and half to have at least 3 decayed teeth. OUTCOME MEASURES: Parents completed a questionnaire, developed using psychological models, on their beliefs, attitudes and behaviours related to their child's oral health. 10% of children had plaque sampled. RESULTS: 2,822 children and families were recruited. In multivariate analyses, reported toothbrushing behaviours that doubled the odds of being caries-free were a combination of brushing before age 1, brushing twice a day and adult involvement in brushing. Analyses combining beliefs, attitudes and behaviours found that parents' perceived ability to implement regular toothbrushing into their child's daily routine was the most important predictor of whether children had caries and this factor persisted in children from disadvantaged communities. 90% of children with lactobacillus had caries. CONCLUSIONS: Parental beliefs and attitudes play a key role in moderating oral health related behaviour in young children and in determining whether they develop caries. Further research is indicated to determine whether supporting the development of parenting skills would reduce dental caries in children from disadvantaged communities independent of ethnic origin.

Adult↗

PubMed2003

Artificial mouth model systems and their contribution to caries research: a review.

The complexity of the oral environment, and ethical problems associated with studies of oral diseases in humans inevitably directed the attention to development of laboratory models, that simulate the human oral microcosm. These developments and in particular the in vitro 'artificial mouth' systems have progressed from simple and basic apparatus devised by Magitot and Miller at the end of 19th century to the currently available, highly sophisticated, computer-controlled, multi-station artificial mouth systems. These advances have metamorphosed from the early studies devised primarily to investigate factors affecting the carious process to the present designs that evaluate growth, pathogenicity, metabolism and mineralization of dental plaque under highly controlled conditions. The modern 'artificial mouth systems' can evaluate microbial interactions in simulated dental plaque and similar biofilms and monitor their physical, chemical, biological and molecular features to a very high degree of accuracy. We review and trace here the historical aspects and developments leading to the currently available artificial mouth systems and discuss their contribution to the study of oral flora, especially related to many variants of dental caries.

Biofilms↗