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Factors Controlling the Microflora of the Healthy Mouth
Published in Michael J. Hill, Philip D. Marsh, Human Microbial Ecology, 2020
The mouth is a moist environment with a stable temperature of 34 to 36°C and a pH close to neutrality in most areas, although sugar consumption may cause a temporary drop to pH = 4 to 5 in dental plaque. A wide range of oxygen tensions and oxidation reduction potentials are found in different areas of the mouth. Saliva is the source of a continuous supply of low concentrations of nutrients, while dietary intakes supply extra nutrients in intermittent pulses of high concentrations. An inflammatory exudate from the gingival tissues, named crevicular fluid (gingival pocket fluid, or gingival exudate), enters the gingival sulcus (crevice) area and periodontal pockets through the epithelium in cases of gingivitis and periodontitis.133 Small quantities of interstitial fluid may pass into the gingival sulcus even in the absence of inflammation. The crevicular fluid supplies nutrients for microorganisms in these locations. It may be supplemented with blood, as bleeding is common in inflamed gingiva. Some aspects of the above-mentioned determinants of oral growth conditions are discussed in the following sections.
Infection-driven periodontal disease
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Thomas E. Van Dyke, Mike Curtis
The early lesion of periodontitis is a more mature leukocyte infiltrate in which neutrophils no longer dominate. The absolute number of neutrophils does not decline, but the main infiltrating cell types are lymphocytes with increasing numbers of lymphoblasts and a few peripheral plasma cells. Mononuclear phagocytes and macrophages also accumulate and maintain a proinflammatory phenotype contributing to the chronicity of the lesion. Collagen loss may reach 80%, and there is loss of fibroblasts and matrix. An exudate forms and flows through the gingival sulcus.
The gastrointestinal system
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Sharon J. White, Francis A. Carey
Disease of the periodontal tissues presents as inflammation of the gingival tissues (gingivitis) or involves the gingivae, the periodontal ligament, and the related alveolar bone (periodontitis). Recent new classification of periodontal disease divides periodontal conditions into four categories: periodontal health, gingival disease and conditions, periodontitis, other conditions affecting the periodontium, and peri-implant diseases and conditions. The most common of these is gingivitis (Figure 10.3), which does not result in the loss of attachment of the periodontal tissues, is reversible and is usually caused by dental plaque but may also be influenced by other factors such as a genetic susceptibility. Periodontitis is measured in Stages (1–4) and Grades (A–C). The higher the stage the more advanced the disease. Grading reflects the rate of progression of disease and the risk of future progression A (slow progression), B (moderate rate of progression), or C (rapid progression). Local and systemic factors influence periodontitis, the most important of which is bacterial plaque within the pocket around the tooth. The inflammation in periodontitis results in the progressive loss of attachment of the periodontal ligament. The deepening of the gingival sulcus occurs with the formation of deep pockets. Prolonged inflammation results in osteoclastic resorption of the alveolar bone which leads to a lack of support and subsequent tooth loss if allowed to progress. Infrequently there may be an acute exacerbation of infection in such pockets and a periodontal abscess can develop.
Critical roles of adherens junctions in diseases of the oral mucosa
Published in Tissue Barriers, 2023
Christina Kingsley, Antonis Kourtidis
The gingival epithelium has been extensively studied due to its implication in periodontal disease. The gingival epithelium is composed of keratinizing stratified epithelium and covers the external surface of the gingiva, which surrounds the teeth (Figure 1).6 An important function of the gingival epithelium is to provide the first line of defense in the oral cavity against pathogens.7 There are several components of the gingiva. The attached gingiva is firmly bonded to the connective tissue over the alveolar bone and is separated from the oral mucosa by the mucogingival line (Figure 1). The attached gingiva is located apically to the gingival sulcus, which is the space surrounding each tooth and is lined by the oral sulcular epithelium (Box 1; Figure 1). This epithelium is stratified and non-keratinized.2 The junctional epithelium is a specialized epithelial component. This epithelium is derived from the enamel epithelium and mediates the attachment of the gingival epithelium to the enamel on the tooth surface (Figure 1).8 This is an important function of the junctional epithelium, because it forms a barrier against pathogens passing from the oral cavity into the tissue that supports the tooth.9 Due to its role, the junctional epithelium isan area of extensive study in periodontal disease,10 where tooth mobility and loss are found. In comparison to the gingival epithelium, the junctional epithelium shows no keratinization and exhibits much higher proliferation and turnover rate2,7,8 (Figure 1).
Incorporation of zinc into cetylpyridinium chloride mouthwash affects the composition of multispecies biofilms
Published in Biofouling, 2023
Willy Bustillos Torrez, Luciene Cristina Figueiredo, Thalita Dias Silva Santos, Geisla Mary Soares, João Marcos Spessoto Pingueiro, Hélio Doyle Pereira da Silva, Zilson Malheiros, Bernal Stewart, Magda Feres, Bruno Bueno-Silva
Biofilm models may be considered as the starting point to study new antimicrobials. Taking this into account, the present multispecies in vitro biofilm model was proposed (Soares et al. 2015) and was shown to present a high complexity due to the number of microorganisms included (Coenye and Nelis 2010; Prado et al. 2022). To the best of our knowledge, this biofilm model includes the largest number of microorganisms as well as members of the supra and subgingival biofilm (Miranda et al. 2019; Pingueiro et al. 2019; Miranda et al. 2020). However, one of its limitations consists of the absence of crevicular fluid of the gingival sulcus (Arweiler et al. 2018). Additionally, it should be noted that while this study reports novel information about the in vitro antimicrobial effect of CPC + Zn, clinical studies are necessary in order to support the benefits of this formulation over those obtained with CHX or CPC alone.
Approximal plaque pH lowering after sugar intake in a periodontally infected dentition
Published in Acta Odontologica Scandinavica, 2021
The plaque pH is widely used for caries risk assessments [1], its significance in relation to periodontal disease, on the other hand, has not been investigated as extensively. In a recent in vitro study, it has been shown that the metabolic activity of biofilms representing periodontal disease (including species like Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola) was highest at pH 7.0–7.5 while cariogenic bacteria (including Streptococcus gordonii, Actinomyces naeslundii, Streptococcus mutans) thrived best at pH 5.5–6.0 [2]. In growing supra- and subgingival biofilms in vivo saccharolytic species, for example, Streptococcus ssp. and Actinomyces ssp., dominate initially. From day four, however, in both healthy and periodontally diseased individuals, a subgingival shift to an asaccherolytic proteolytic microbiota, for example, Campylobacter rectus, Campylobacter showae, Capnocytophaga ochracea and Prevotella nigrescens was seen [3]. As a result, signs of inflammation occur at the gingival margin and the flow of the gingival crevicular fluid (GCF) – a serum-like fluid derived from blood vessels in the gingival sulcus – increases [4]. While only traces of GCF are detectable in gingival health [5], clinical signs of inflammation usually are accompanied by higher volumes [6–8] and higher pH of the GCF [9–11]. In contrast, bacteria in the supragingival environment metabolize typically glucose, creating an acidic environment and favouring acid-tolerant microorganisms [12].