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Alveolar bone is the thickened ridge of jaw bone that supports teeth. It is subject to constant occlusal force and pathogens invasion, and is therefore under active bone remodeling and immunomodulation. Alveolar bone holds a distinct niche from long bone considering their different developmental origin and postnatal remodeling pattern. However, a systematic explanation of alveolar bone at single-cell level is still lacking. Here, we construct a single-cell atlas of mouse mandibular alveolar bone through single-cell RNA sequencing (scRNA-seq). A more active immune microenvironment is identified in alveolar bone, with a higher proportion of mature immune cells than in long bone. Among all immune cell populations, the monocyte/macrophage subpopulation most actively interacts with mesenchymal stem cells (MSCs) subpopulation. Alveolar bone monocytes/macrophages express a higher level of Oncostatin M (Osm) compared to long bone, which promotes osteogenic differentiation and inhibits adipogenic differentiation of MSCs. In summary, our study reveals a unique immune microenvironment of alveolar bone, which may provide a more precise immune-modulatory target for therapeutic treatment of oral diseases. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this cross-sectional study was to profile complete denture wearers in 2 different unmatched and nonrandomized population groups and compare any possible relationships between the prevalence of denture stomatitis and other factors involved in wearing complete dentures. Materials and Methods: Denture wearers who attended the clinics of the Dental School and Hospital, University of Bristol, United Kingdom (group A), and the Dental School, University of Athens, Greece (group B), were examined. The examination included a record of gender, age, years wearing a complete denture, number of dentures used, duration of current denture's usage, daily time period of denture wearing, and clinical examination of the maxillary denture-bearing mucosa. Data were analyzed using the chi-square test. Results: Denture wearers of group A were older, more experienced in wearing complete dentures, and had used more sets of dentures. The majority of patients used dentures exhibiting decreased vertical dimension of occlusion and wore their dentures only in the daytime. Denture stomatitis prevalence was statistically significantly different between groups A and B (27% and 39.7%, respectively). In both groups, the denture stomatitis prevalence was greater in women. There was no statistically significant difference between the groups regarding the age of denture wearers, the number of dentures used, or the vertical dimension of occlusion. In group B, the denture stomatitis prevalence was significantly related to the years of denture-wearing experience and the current denture's usage. In both groups, continuous denture wearing was highly related to denture stomatitis prevalence. Conclusions: This cross-sectional study showed that 2 different population groups of denture wearers presented different complete denture wearing habits and denture stomatitis prevalence. Comparisons indicate that proper denture wearing habits decrease the prevalence of denture stomatitis. Int J Prosthodont 2006;19:621-625. [ABSTRACT FROM AUTHOR]

Sex is a biological variable that affects immune responses to bacterial and other types of infectious agents. Males and females are known to have differential oral bacterial disease burden in periodontal and endodontic disease. Understanding that there is a contribution from both sex and gender to these oral diseases, we discuss in this review recent sex-based findings that provide a pathobiological basis for differences observed between males and females. Sexual dimorphism of immune responses with respect to neutrophil trafficking and osteoclast differentiation and formation is presented as a plausible mechanism to explain the sexual differences. We also emphasize that sex, as a biological variable, should be considered in these types of oral immunologic studies. [ABSTRACT FROM AUTHOR]

Objective: To determine the patterns of tobacco usage among subjects with potentially malignant oral lesions or conditions through a comparative study design.Methods: The study was carried out in a span of 2 months on a sample of 120 subjects; 60 in case group (30 subjects with leukoplakia and oral submucous fibrosis [OSMF], respectively) and 60 subjects in control group (30 current smokers and current chewers, respectively), attending the tobacco cessation clinic at a private dental college hospital in Chennai city. Demographic data, details of tobacco usage, and Fagerstrom nicotine dependence scores (FNTD) were recorded in a prevalidated tobacco cessation intake form.Results: Cases with leukoplakia had a higher mean FNTD score when compared to the control group (P = 0.0001). The most common form of smokeless tobacco used by case (OSMF) subjects was found to be mawa (53%) significantly higher than the control group (P = 0.05). Mean FNTD scores of mawa users were higher than other tobacco users in both case and control group.Conclusion: The current study has hence put forth the role of mawa form of tobacco in causation of OSMF at a time when implementation of tougher anti-tobacco laws is the talk of the town. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of chronic continuous hypoxia (CCH) in alveolar bone and its correlation with the inflammatory markers which play a key role in the development of periodontitis. Material and methods Wistar rats were exposed to CCH (600 mbar, 3 months). Macroscopic and histological analyses of alveolar bone were performed, together with measurement of oxidative stress and inflammatory parameters in gums and submandibular glands (SMG). Results HCC induced cortical alveolar bone loss, decreased interradicular bone volume and increased the periodontal ligament height compared to control rats (p < 0.05). CCH enhanced iNOS activity in gums (from 2735,04 ± 662,96 nmol/min/mg proteins to 4289,58 ± 915,63 p < 0.05) and in SMG (from 56,71 ± 12,05 nmol/min/mg proteins to 90,15 ± 21,78 p < 0.05). PGE 2 did not change in gums or in SMG by means of CCH, while TNFα decreased in gums (p < 0.05). Regarding oxidative stress, thiobarbituric acid reactive species concentration in CCH animals was higher both in gums as in SMG, and catalase activity was decreased in SMG. Conclusion Higher iNOS activity both in gums and SMG under CCH could be associated with the alveolar bone loss observed. The increase in oxidative stress occurring in SMG and gums, together with a lower antioxidant capacity might indicate a deleterious effect of HX in oral health. [ABSTRACT FROM AUTHOR]

The article offers information on oral submucous fibrosis (OSMF), a chronic disease of the mouth. Topics discussed include factors contributing to the disease such as areca nut chewing, ingestion of chillies and genetic and immunological processes, a study conducted in Durban, South Africa related to male to female ratio of OSMF, and need of a habit of non-addiction of chewing areca nut and pan as a remedy for the disease.

Oral Diseases (2010) 16, 696-701 Objectives: Hypoxia inducible factor (HIF)-1α gene expression is mainly induced by tissue hypoxia. Overexpression of HIF-1α has been demonstrated in a variety of cancers. The aim of this study was to compare HIF-1α expression in normal human oral epithelium and areca quid chewing-associated oral squamous cell carcinoma (OSCC) and further to explore the potential mechanisms that may lead to induce HIF-1α expression. Methods: Twenty-five OSCC from areca quid chewing-associated OSCC and 10 normal oral tissue biopsy samples without areca quid chewing were analyzed by immunohistochemistry. The oral epithelial cell line GNM cells were challenged with arecoline, a major areca nut alkaloid, by using Western blot analysis. Furthermore, glutathione precursor N-acetyl-l-cysteine (NAC), AP-1 inhibitor curcumin, extracellular signal-regulated protein kinase inhibitor PD98059, and protein kinase C inhibitor staurosporine were added to find the possible regulatory mechanisms. Results: Hypoxia inducible factor-1α expression was significantly higher in OSCC specimens than normal specimen ( P < 0.05). Arecoline was found to elevate HIF-1α expression in a dose- and time-dependent manner ( P < 0.05). The addition of NAC, curcumin, PD98059, and staurosporine markedly inhibited the arecoline-induced HIF-1α expression ( P < 0.05). Conclusions: Hypoxia inducible factor-1α expression is significantly upregulated in areca quid chewing-associated OSCC and HIF-1α expression induced by arecoline is downregulated by NAC, curcumin, PD98059, and staurosporine. [ABSTRACT FROM AUTHOR]

Summary: Using a model of lethal oral infection with Toxoplasma gondii, we examined the fate of both induced and natural regulatory T (Treg) cells in the face of strong inflammatory responses occurring in a tolerogenic-prone environment. We found that during highly T helper 1 (Th1) cell-polarized mucosal immune responses, Treg cell numbers collapsed via multiple pathways, including blockade of Treg cell induction and disruption of endogenous Treg cell homeostasis. In particular, shutdown of interleukin 2 (IL-2) in the highly Th1 cell-polarized environment triggered by infection directly contributes to Treg cell incapacity to suppress effector responses and eventually leads to immunopathogenesis. Furthermore, we found that environmental cues provided by both local dendritic cells and effector T cells can induce the expression of T-bet transcription factor and IFN-γ by Treg cells. These data reveal a mechanism for Th1 cell pathogenicity that extends beyond their proinflammatory program to limit Treg cell survival. [Copyright &y& Elsevier]

Bacteria in the human oral cavity often grow in an attached multispecies biofilm community. Members of this community display defined interactions that have an impact on the physiology of the individual and the group. Here, we show that during coculture growth with streptococci, the oral pathogen Aggregatibacter actinomycetemcomitans displays enhanced resistance to killing by host innate immunity. The mechanism of resistance involves sensing of the streptococcal metabolite hydrogen peroxide by A. actinomycetemcomitans, which stimulates a genetic program resuiting in enhanced expression of the complement resistance protein ApiA. The oxidative stress response regulator OxyR mediates induction of apiA transcription, and this induction is required for coculture resistance to killing by human serum. These findings provide evidence that interaction between community members mediates prokaryotic resistance to host innate immunity and reinforce the need to understand how polymicrobial growth affects interaction with the host immune system. [ABSTRACT FROM AUTHOR]

El artículo afirma que el fenotipo de los linfocitos T pueden contribuir a la enfermedad periodontal. Asevera que el perfil Th1/Th2 en el área de inflamación incide en el resultado de la enfermedad. Nota que los linfocitos T activados por la respuesta inmunitaria del hospedador pueden promover la osteoclastogénesis. Propone que el equilibrio entre los linfocitos Th1 y Th2 en el área de inflamación determina la destrucción periodontal.

El artículo trata el rol de los linfocitos B en la periodontitis. Informa que los leucocitos y linfocitos representan la gran mayoría de las células inflamatorias en las lesiones de periodontitis. Nota que los linfocitos B internalizan los antígenos a través de receptores Ig ubicados en las membranas celulares y que esto constituye una respuesta inmunitaria eficaz contra bajos niveles de antígenos.

El artículo trata los diferentes niveles de inmunidad en los seres humanos en el contexto de la inflamación periodontal. Informa que la enfermedad periodontal inflamatoria crónica ocurre cuando, el resultado de respuestas inmunitarias innatas y adaptivas, las bacterias orales dañan las células epiteliales. Examina en particular la susceptabilidad a la inflamación, la variación de los receptores tipo Toll en las personas y las variabilidad en la señalización entre otros factores.

The purpose of this work was to evaluate the influence of Pro- tease Inhibitors (PI) on the occurrence of oral candidiasis in 111 HIV+ patients under PT therapy (Group A). The controls consisted of 56 patients that were not using PI drugs (Group B) and 26 patients that were not using any drugs for HIV therapy (Group C). The patient's cd4 cell counts were taken in account for the correlations. One hundred and ninety three patients were evaluated. The PI did not affect the prevalence of oral candidiasis (p = 0.158) or the frequency of C. albicans isolates (p = 0.133). Patients with lower cd4 cell counts showed a higher frequency of C. albicans isolates (p = 0.046) and a greater occurrence of oral candidiasis (p = 0.036). [ABSTRACT FROM AUTHOR]

El artículo examina los efectos del tratamiento del cáncer en la salud bucal. Informa que se descubren más de un millón de casos de cáncer en los Estados Unidos cada año. Describe los métodos empleados en el tratamiento del cáncer, incluso la cirugía, radiación y quimoterapia. Informa que la boca es susceptible a los efectos secundarios de la quimoterapia. En particular, nota que la boca puede convertirse en una fuente para la infección sistémica en los pacientes inmunodeprimidos.

Some of the most frequent extrahepatic manifestations of hepatitis C virus (HCV) infection involve the oral region predominantly or exclusively. Part 2 of this review discusses the current evidences regarding the association of lichen planus (LP) and other diseases frequently involving the oral cavity with HCV. Epidemiological data suggest that LP may be significantly associated with HCV infections especially in southern Europe and Japan but not in northern Europe. These geographical differences are possibly influenced by immunogenetic factors, the duration of the HCV infection and the design of the published studies. Because of the fact that most of the studies published are retrospective, it is impossible to establish whether the HCV exposure occurred earlier to or after the onset of disease and more prospective studies are clearly warranted. As the virus may replicate in the skin and oral mucosa and HCV-specific T lymphocytes can be found in the oral mucosa of patients with chronic hepatitis C and LP, HCV may be implicated in the pathogenesis of LP. However, little attention has been paid to the variable effect of therapy with interferon-alpha (IFN-α), with or without ribavirin for LP. Conversely, it is unlikely that other oral diseases such as oral carcinoma, pemphigus and Behcet disease are triggered by HCV. [ABSTRACT FROM AUTHOR]

El artículo trata la respuesta del hospedador a los microorganismos patológicos relacionados con enfermedades periodontales. Afirma que las infecciones bucales pueden influir en la aparición de condiciones médicas de tipo sistémico. Nota que los antígenos en general pueden provocar una reacción inflamatoria en el hospedador que destruye el ligamento periodontal y el hueso. Menciona factores de riesgo para la enfermedad periodontal, entre ellos el fumar, la obesidad y el diabetes.

This study reports denture stomatitis (DS) prevalence from a large USA probability sample from the National Health and Nutrition Examination Survey, 1988–1994 (NHANES III).Oral examinations were performed on 3450 individuals 18–90+ years of age (mean: 59.2; SD: 0.50 years), 57.7% male and 42.3% female. Multivariable logistic regression models were fitted for DS using sociodemographic, denture quality, blood analytes, alcohol and tobacco use, history of diabetes, and current antibiotic use as covariates. Odds ratios (OR), adjusted for other covariates in each model (AOR) are presented.Of 3450 removable denture wearers, 963 (27.9%) had DS. DS prevalence was associated with wearing maxillary (AOR: 6.20) and mandibular (AOR: 5.21) complete dentures continuously; smoking≥15 cigarettes day (maxillary complete: AOR = 1.31; mandibular complete: AOR = 1.50; maxillary partial: AOR = 2.04); vitamin A deficiency (mandibular complete: AOR = 5.97; maxillary partial: AOR = 5.67; mandibular partial: AOR = 24.42). Maxillary dentures with inadequate relines had approximately half the OR of DS than those with adequate relines (maxillary complete: AOR = 0.42; mandibular complete: AOR = 0.50).Denture stomatitis prevalence is associated with the amount of tissue covered by dentures, low vitamin A levels, cigarette smoking, and constant denture wear.J Oral Pathol Med(2005)34: 340–6 [ABSTRACT FROM AUTHOR]

Oral fungal infections (mycoses) have come into particular prominence since the advent of infection with Human Immunodeficiency Virus (HIV), and recognition of the Acquired Immune Deficiency Syndrome (AIDS), as well as the phenomenal increase in world travel with increased exposure to infections endemic in the tropics. Paracoccidioidomycosis is a rare mycosis worldwide but common in Brazil and some other areas in Latin America. It can be life-threatening and can manifest with a spectrum of clinical presentations, including frequent oral lesions. This paper reviews the more recent information on Paracoccidioidomycosis, emphasizing those areas most relevant in dental science. [ABSTRACT FROM AUTHOR]

Mast cells are mobile granule-containing secretory cells that are distributed preferentially about the microvascular endothelium in oral mucosa and dental pulp. The enzyme profile of mast cells in oral tissues resembles that of skin, with most mast cells expressing the serine proteases tryptase and chymase. Mast cells in oral tissues contain the pro-inflammatory cytokine tumour necrosis factor-a in their granules, and release of this promotes leukocyte infiltration during evolving inflammation in several conditions, including lichen planus, gingivitis, pulpitis, and periapical inflammation, through induction of endothelial-leukocyte adhesion molecules. Mast cell synthesis and release of other mediators exerts potent immunoregulatory effects on other cell types, while several T-lymphocyte-derived cytokines influence mast cell migration and mediator release. Mast cell proteases may contribute to alterations in basement membranes in inflammation in the oral cavity, such as the disruptions that allow cytotoxic lymphocytes to enter the epithelium in oral lichen planus. A close relationship exists among mast cells, neural elements, and laminin, and this explains the preferential distribution of mast cells in tissues. Mast cells are responsive to neuropeptides and, through their interaction with neural elements, form a neural immune network with Langerhans cells in mucosal tissues. This facilitates mast cell degranulation in response to a range of immunological and non-immunological stimuli. Because mast cells play a pivotal role in inflammation, therapies that target mast cell functions could have value in the treatment of chronic inflammatory disorders in the oral cavity. [ABSTRACT FROM AUTHOR]

Oral mucosal barrier injury (mucositis) is a frequent, painful, serious, dose-limiting toxicity associated with many anti-neoplastic drugs and radiation to the head and neck. Results of recent studies suggest that mucositis is the result of a complex series of interactive biological events that take place in the submucosa and epithelium. The nuclear transcription factor NF-κB has been implicated in the control of a broad range of biological responses, the activation of a large number of specific cellular genes, and the determination of the fate of cells exposed to ionizing radiation and anti-neoplastic drugs. Of particular importance to mucositis is the fact that NF-κB regulates key elements in the apparent sequence that leads to normal tissue toxicity. Not the least of these is the effect that NF-κB activation has on apoptosis. In particular, a paradox exists between the potential pro-apoptotic effect NF-κB exerts on normal cells, and the anti-apoptotic and cytoprotective effect it causes in tumor cells. This paper provides a review of the structure and function of NF-κB and speculates how its apparent enigmatic effect on normal and tumor cells may occur. [ABSTRACT FROM AUTHOR]

Both antigen-specific and non-specific mechanisms may be involved in the pathogenesis of oral lichen planus (OLP). Antigen-specific mechanisms in OLP include antigen presentation by basal keratinocytes and antigen-specific keratinocyte killing by CD8+ cytotoxic T-cells. Non-specific mechanisms include mast cell degranulation and matrix metalloproteinase (MMP) activation in OLP lesions. These mechanisms may combine to cause T-cell accumulation in the superficial lamina propria, basement membrane disruption, intra-epithelial T-cell migration, and keratinocyte apoptosis in OLP. OLP chronicity may be due, in part, to deficient antigen-specific TGF-β1-mediated immunosuppression. The normal oral mucosa may be an immune privileged site (similar to the eye, testis, and placenta), and breakdown of immune privilege could result in OLP and possibly other autoimmune oral mucosal diseases. Recent findings in mucocutaneous graft-versus-host disease, a clinical and histological correlate of lichen planus, suggest the involvement of TNF-α, CD40, Fas, MMPs, and mast cell degranulation in disease pathogenesis. Potential roles for oral Langerhans cells and the regional lymphatics in OLP lesion formation and chronicity are discussed. Carcinogenesis in OLP may be regulated by the integrated signal from various tumor inhibitors (TGF-β1, TNFα, IFN-γ, IL-12) and promoters (MIF, MMP-9). We present our recent data implicating antigen-specific and non-specific mechanisms in the pathogenesis of OLP and propose a unifying hypothesis suggesting that both may be involved in lesion development. The initial event in OLP lesion formation and the factors that determine OLP susceptibility are unknown. [ABSTRACT FROM AUTHOR]

Strategies aimed at the prevention of Streptococcus mutans infection and dental caries include mucosal immunization, which results in salivary anti-S. mutans responses. The purpose of this study was to evaluate the effectiveness of nasal vs. tonsillar immunization with S. mutans antigens in inducing salivary immune responses. Twenty-one adult subjects were immunized twice, within a seven-day interval, with a glucosyltransferase-enriched preparation (E-GTF) administered by nasal or tonsillar topical spray. Parotid saliva, nasal wash, and serum were collected prior to and at one- to two-week intervals for 3 months following immunization and were assayed by ELISA for anti-E-GTF activity. Results were analyzed by means of the mixed-models procedure with p < 0.05 level of significance. Significantly higher anti-E-GTF responses were detected in saliva and nasal wash samples from the group immunized by the nasal compared with the tonsillar route, indicating that nasal immunization was more effective in inducing mucosal responses in adults. [ABSTRACT FROM AUTHOR]

Adhesion of Candida cells to oral surfaces is an initial event in pathogenesis. Since specific immobilized salivary components mediate the binding of Candida albicans to hydroxyapatite, we hypothesized that saliva may also promote adherence to oral epithelia via a similar mechanism. In an in vitro model, C. albicans ATCC 10261 yeast cells adhered in a saturable manner to monolayers of three cultured human epithelial cell lines (A549, HEp-2, and HET-1A). The addition of whole saliva to the assay promoted the binding of C. albicans to all cell lines in a dose-dependent manner, but preincubation of the epithelial cells with pooled whole saliva had no effect on subsequent adherence. Pre-incubation of the yeast cells with pooled whole saliva, however, significantly enhanced (by up to 120%, P < 0.05) binding to epithelial cell monolayers, and pooled saliva that had been pre-incubated with C. albicans yeast cells was defective in promoting yeast adherence. There was a negative correlation (r = 0.68, P < 0.005) between specific IgA titers against whole cells of C. albicans and adherence-promoting activities for individual saliva samples. The adhesion-inhibitory effect of specific anti- C. albicans IgA was reversed by depletion of IgA from saliva by affinity chromatography. Factors in whole saliva, therefore, bound to the yeast cells, counter the C. albicans-specific salivary IgA inhibitory effect on adhesion and promote the adherence of C. albicans yeast cells to cultured epithelial cells. [ABSTRACT FROM AUTHOR]

The article presents a study regarding the induction of oral tolerance in various strains of mice. The author explains that antigenic contacts may induce the production of secretory IgA specific antibodies at the local site of mucosal stimulation, as well as more distant sites. The results indicate that oral immunization occurs optimally at a certain age interval.

Oral infections are among the first manifestations of infection by the human immunodeficiency virus (HIV). They include fungal, viral, and bacterial infections and range from being essentially trivial, through troublesome to life threatening. Although some infections are due to overproliferation of the normal oral flora, others are due to organisms that normally are not found in the mouth. The clinical features of many of these infections have now been characterized, and clinical trials have indicated the optimal management. However, for many infections, the underlying processes are still not clear, and improvements in treatment are necessary. [ABSTRACT FROM AUTHOR]

In this study, the modulation of adherence of hydrogen peroxide (H2O2)-producing and non-H2O2-producing strains of oral streptococci by the host leukocyte enzyme myeloperoxidase (MPO) was examined. It was found that exposure to MPO decreased adherence of many strains of oral streptococci to saliva-coated hydroxyapatite beads in the presence of exogenous H2O2 and chloride. The MPO-H2O2-Cl- system increased the adherence of one strain. In the absence of exogenous H2O2, the MPO-H2O2-Cl- system decreased the adherence of H2O2-producing strains only. Glucose increased streptococcal H2O2 production and also increased the anti-adhesive activity of MPO in the absence of exogenous H2O2. We conclude that: (1) host leukocytes can modulate the adherence of oral streptococci via MPG; (2) endogenous production of H2O2 by the oral streptococci can provide sufficient substrate H2O2 to drive this system; and (3) MPO will exert differential modulatory effects on the adherence of oral streptococci, based in part upon the level of endogenous H2O2 production and in part upon the particular characteristics of the adhesins of the bacteria. [ABSTRACT FROM AUTHOR]

Levels of immunoglobulin class-specific antibodies as determined by solid phase radioimmunoassays to herpes simplex virus type 1 (HSV-1), human adenovirus types 5, 21, and 31 and to Candida albicans in sera from untreated healthy dental patients were not significantly different from levels of these antibodies in sera from untreated dental patients with benign oral tumors, oral carcinoma, or periodontal disease. These results show that higher levels of immunoglobulin class-specific antibodies to HSV-1, the three adenoviruses, or Candida albicans are not a consistent finding in sera from patients with oral cancer when comparisons are made with healthy patients and patients with other oral diseases. [ABSTRACT FROM AUTHOR]

The article discusses the aims and objective of the periodical published by the organization Indian Dental Association (IDA) which is to highlight the importance of oral health and to create awareness of oral hygiene for preventing oral ailments. Topics discussed include mouth as the most sensitive biological indicator of oral health status, effect of nutritional deficiencies and blood disorders on mouth, and prevalence of oral cancer in India.