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Background: Vascular endothelial growth factor (VEGF) is a master regulator and is required for the effective coupling of angiogenesis and osteogenesis supporting both skeletal development and postnatal bone repair. A direct role for VEGF in intramembranous-derived osteoblast growth and differentiation is not clear. We investigated the expression of primary alveolar osteoblast VEGF receptors and the subsequent effects on mineralization and nodule formation in vitro following VEGFR inhibition.Methods: Primary human alveolar osteoblasts (HAOBs) were cultured in the presence of VEGF receptor inhibitors, exogenous VEGF or the bisphosphonate, zoledronic acid. VEGF, VEGFR1 and VEGFR2 mRNA expression and nodule formation following 21 days of culture. VEGFR1 protein expression was examined using immunofluorescence after 48 h.Results: The HAOBs expressed high levels of VEGF and VEGFR1 protein but VEGFR2 was not detected. The VEGFR1/2 inhibitors, ZM306416 and KRN633, lead to a dose-dependent decrease in mineralization. Treatment with zoledronic acid showed no difference in HAOB VEGF receptor expression.Conclusion: VEGF/VEGFR1 pathway appears to be important for intramembranous-derived osteoblast differentiation and maturation in vitro. [ABSTRACT FROM AUTHOR]

An abstract of the article "The effect of infection with Porphyromonas gingivalis on atherogenesis in a murine model" by P. J. Ford, E. Gemmell, P. S. Bird, and G. J. Seymour is presented.

The aim of the study was to evaluate the association between salivary anti-Porphyromonas gingivalis IgA antibodies and the leprosy reaction. The levels of salivary anti - P. gingivalis IgA antibodies, together with salivary flow and pH were measured in individuals diagnosed with leprosy and associated with the development of the leprosy reaction. Saliva was collected from 202 individuals diagnosed with leprosy at a reference leprosy treatment center, 106 cases with the leprosy reaction and 96 controls without the leprosy reaction. Anti - P. gingivalis IgA was evaluated by indirect immunoenzyme assay. Non-conditional logistic regression analysis was employed to estimate the association between antibody levels and the leprosy reaction. There was a positive statistically significant association between the levels of anti - P. gingivalis IgA and the presence of the leprosy reaction, controlling for confounders: age, sex, level of education and alcoholic beverage consumption: OR ajusted : 2.55; IC 95%: 1.34-4.87. Individuals with leprosy who had high levels of salivary anti - P. gingivalis IgA had approximately twice as many chances of developing the leprosy reaction. The findings suggest a possible relationship between salivary anti - P. gingivalis IgA antibodies and the leprosy reaction., (© 2023. The Author(s).)

The Interleukin (IL)-33 is important in several inflammatory diseases and its cellular receptor is the Interleukin 1 receptor-like 1 (IL1RL1), also called suppression of tumorigenicity 2 ligand (ST2L). This study investigated associations between single nucleotide variants (SNVs) in the IL33 gene and in the IL1RL1 (ST2) gene with periodontitis. Additionally, aimed to determine the role of Aggregatibacter actinomycetemcomitans (Aa) relative amount in the subgingival biofilm in these associations. A cross-sectional study was carried out with 506 individuals that answered a structured questionnaire used to collect their health status, socioeconomic-demographic, and behavioral characteristics. Periodontal examination was performed to determine the presence and severity of periodontitis, and subgingival biofilm samples were collected to quantify the relative amount of Aa by real time polymerase chain reaction. Human genomic DNA was extracted from whole blood cells and SNV genotyping was performed. Logistic regression estimated the association measurements, odds ratio (OR), and 95% confidence interval (95%CI), between the IL33 and ST2 genes with periodontitis, and subgroup analyses assessed the relative amount of Aa in these associations. 23% of individuals had periodontitis. Adjusted measurements showed a statistically significant inverse association between two SNVs of the ST2; rs148548829 (C allele) and rs10206753 (G allele). These two alleles together with a third SNV, the rs11693204 (A allele), were inversely associated with moderate periodontitis. One SNV of the IL33 gene also showed a statistically significant inverse association with moderate periodontitis. Nine SNVs of the ST2 gene were inversely associated with the relative amount of Aa. In the high Aa subgroup, there was a direct association between 11 SNVs of the ST2 gene and moderate periodontitis and two SNVs of the ST2 gene and severe periodontitis, and eight SNVs of the ST2 gene and periodontitis. These exploratory findings of genetic variants in IL-33/ST2 axis support the concept that the different tissue responses among individuals with periodontitis may be modulated by the host's genetics, influencing the physiopathology of the disease., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Trindade et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

While periodontal disease is associated with many risk factors, socioeconomically disadvantaged communities experience the highest disease burden. The aim of this study was to evaluate the effectiveness of a personalized oral health education program, in combination with routine dental treatment, in participants from a low socioeconomic community. We used a randomized, controlled, examiner-blinded clinical trial. A total of 579 participants (aged 18-60 years) were randomly grouped: the intervention group (n = 292) received a personalized oral health education program in combination with routine dental care and the control group (n = 287) received routine dental care. All participants were assessed for improvement in oral health care behaviors, dental plaque, and periodontal status at baseline, 12 months, and 24 months. We found a significant drop ( p < 0.001) in the plaque indices, Periodontal Probing Depths (PPD) and Bleeding on Probing (BOP) between baseline and the 12-month follow-up for both groups. For BOP, the number of sites positive was significantly different between baseline and the 24-month follow-up ( p = 0.037). No differences were found between the two groups for any evaluated clinical outcome. The personalized oral health education program used in the current study did not appear to add significant improvement to clinical outcomes of periodontal health compared with routine restorative dental care per se.

Objective: To determine the association between the presence of periodontal pathogens and low birthweight., Methods: This observational and case-control study consisted of mothers of infants weighing <2,500g (Group A), and mothers of newborns weighing ≥2,500g (Group B), born at Hospital da Mulher in Feira de Santana (BA), Brazil. A semi-structured questionnaire covering demographic data, gestational history and aspects related to general and oral health was employed postpartum. Following a complete periodontal examination, biofilm samples were collected at six sites in the mouth. The participants were further categorized in terms of presence or absence of periodontitis. Differences between the groups were determined using Pearson's χ 2 test, odds ratio, and confidence intervals were obtained using the Mantel-Haenszel test., Results: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Prevotella intermedia were detected by polymerase chain reaction. A total of 303 postpartum women were evaluated, 224 (73.9%) in Group B. Statistically significant differences between the groups were found for age, body mass index and history of previous low birthweight babies. Group A had a higher frequency of periodontitis (33.34%) than Group B (16.22%). P. gingivalis and P. intermedia were detected more frequently among women with periodontitis (74.19% and 88.70%, respectively)., Conclusion: In this population, there was no association between the presence of maternal periodontal pathogens and the occurrence of low birthweight infants.

Objectives: To examine stakeholder perspectives of the Bachelor of Dental Surgery 2012-2013 clinical outplacement programme with Māori Oral Health Providers (MOHPs) and inform the programme's ongoing development., Design: A mixed methods kaupapa Māori action research project., Setting: Six North Island MOHPs and the University of Otago Faculty of Dentistry., Participants and Methods: Online questionnaires were used to conduct a pre- and post-outplacement survey of dental students and a twice-yearly survey of all MOHP-based clinical supervisors. Paper questionnaires were used to survey adult clients and caregivers of child clients that the students treated. Data were analysed descriptively and thematically., Main Outcome Measures: 68 (61%) of the 112 eligible students completed the pre- and post-outplacement questionnaires; 31 clinical supervisor questionnaire responses were received representing all six MOHPs; and 426 client and 130 caregiver questionnaire responses were received from five MOHPs., Results: 79% of students felt well prepared for outplacement and 75% indicated that they would consider working for a MOHP in future. Of the clinical supervisors, 93% indicated that the students were adequately prepared for outplacement, and 68%, that they would recommend one or more students for employment. However, 58% associated the outplacements with decreased productivity. More than 97% of adult clients and caregivers of child clients were pleased with the care that the students provided., Conclusion: Recommendations for strengthening the outplacement programme included: increasing communication between the Faculty, MOHPs and students; addressing the financial cost of the programme to the MOHPs; and providing more support for clinical supervisors.

It is becoming increasingly apparent that the tumor microenvironment plays an important role in the progression of cancer. The microenvironment may promote tumor cell survival and proliferation or, alternatively may induce tumor cell apoptosis. Toll-like receptors (TLRs) are transmembrane proteins, expressed on immune cells and epithelial cells, that recognize exogenous and endogenous macromolecules. Once activated, they initiate signaling pathways leading to the release of cytokines and chemokines, which recruit immune cells inducing further cytokine production, the production of angiogenic mediators and growth factors, all of which may influence tumor progression. This paper examines the actions of TLRs in carcinogenesis with particular emphasis on their role in oral squamous cell carcinoma.

This study profiled the local and systemic inflammatory responses to experimentally induced gingivitis. Eight females participated in a 21-day experimental gingivitis model followed by a 14-day resolution phase. Bleeding on probing and plaque index scores were assessed before, during, and after resolution of gingival inflammation, and samples of saliva, GCF, and plasma were collected. Samples were assessed for biomarkers of inflammation using the BioPlex platform and ELISA. There were no significant changes in GCF levels of cytokines during the experimental phase; however, individual variability in cytokine profiles was noted. During resolution, mean GCF levels of IL-2, IL-6, and TNF-α decreased and were significantly lower than baseline levels (P = 0.003, P = 0.025, and P = 0.007, resp.). Furthermore, changes in GCF levels of IL-2, IL-6, and TNF-α during resolution correlated with changes in plaque index scores (r = 0.88, P = 0.004; r = 0.72, P = 0.042; r = 0.79, P = 0.019, resp.). Plasma levels of sICAM-1 increased significantly during the experimental phase (P = 0.002) and remained elevated and significantly higher than baseline levels during resolution (P < 0.001). These results support the concept that gingivitis adds to the systemic inflammatory burden of an individual.

Background: The aim of this study was to investigate the expression of toll-like receptor 2 (TLR2) on cells associated with oral squamous cell carcinoma, epithelial dysplasia and irritative hyperplasia, using immunohistochemistry., Results: More immune cells expressed TLR2 in carcinoma and dysplasia than in hyperplasia (P<0.001). No hyperplastic samples showed positive TLR2 staining on keratinocytes, whereas keratinocytes in 64% of cases of carcinoma and 74% of cases of dysplasia were TLR2 positive., Conclusion: Positive TLR2 expression in the microenvironment suggests activation of immune surveillance against the altered epithelium, whereas TLR2 expression by malignant keratinocytes may be indicative of resistance to apoptosis as a pro-survival mechanism.

Rheumatoid arthritis (RA) and periodontal disease (PD) have shown similar physiopathologic mechanisms such as chronic inflammation with adjacent bone resorption in an immunogenetically susceptible host; however, PD has a well-recognized bacterial etiology while the cause of RA is unclear. Some reports have indicated that an infectious agent in a susceptible host could be one possible trigger factor for RA, and it has been suggested that oral microorganisms, specialty periodontal bacteria could be the infectious agent (mainly Porphyromonas gingivalis). It has been reported that PD is more frequent and more severe in patients with RA, suggesting a positive association between both diseases. There have been reports regarding the detection of antibodies against periodontal bacteria while other studies have identified periodontal bacterial DNA in serum and synovial fluid of RA patients and have explored the possible pathways of transport of periodontal bacterial DNA. In conclusion, there is no question that RA and PD have pathologic features in common and there is strong evidence of an association between both diseases, but further studies, including experimental models, are needed to demonstrate the arthritogenicity of oral microorganisms.

Periodontal disease, as a polymicrobial disease, is globally endemic as well as being a global epidemic. It is the leading cause for tooth loss in the adult population and has been positively related to life-threatening systemic diseases such as atherosclerosis and diabetes. As a result, it is clear that more sophisticated therapeutic modalities need to be developed, which may include vaccines. Up to now, however, no periodontal vaccine trial has been successful in satisfying all the requirements; to prevent the colonization of a multiple pathogenic biofilm in the subgingival area, to elicit a high level of effector molecules such as immunoglobulin sufficient to opsonize and phagocytose the invading organisms, to suppress the induced alveolar bone loss, or to stimulate helper T-cell polarization that exerts cytokine functions optimal for protection against bacteria and tissue destruction. This article reviews all the vaccine trials so as to construct a more sophisticated strategy which may be relevant in the future. As an innovative strategy to circumvent these barriers, vaccine trials to stimulate antigen-specific T-cells polarized toward helper T-cells with a regulatory phenotype (Tregs, CD4+, CD25+, FoxP3+) have also been introduced. Targeting not only a single pathogen, but polymicrobial organisms, and targeting not only periodontal disease, but also periodontal disease-triggered systemic disease could be a feasible goal.

The relationship between oral and general health has been increasingly recognised during the past two decades. Several epidemiological studies have linked poor oral health with cardiovascular disease, poor glycaemic control in diabetics, low birth-weight pre-term babies, and a number of other conditions, including rheumatoid arthritis and osteoporosis. Oral infections are also recognised as a problem for individuals suffering from a range of chronic conditions, including cancer and infection with human immunodeficiency virus, as well as patients with ventilator-associated pneumonia. This review considers the systemic consequences of odontogenic infections and the possible mechanisms by which oral infection and inflammation can contribute to cardiovascular disease, as well as the oral conditions associated with medically compromised patients. A large number of clinical studies have established the clinical efficacy of topical antimicrobial agents, e.g., chlorhexidine and triclosan, in the prevention and control of oral disease, especially gingivitis and dental plaque. The possible risks of antimicrobial resistance are a concern, and the benefits of long-term use of triclosan require further evaluation. Oral infections have become an increasingly common risk-factor for systemic disease, which clinicians should take into account. Clinicians should increase their knowledge of oral diseases, and dentists must strengthen their understanding of general medicine, in order to avoid unnecessary risks for infection that originate in the mouth.

Oral conditions such as gingivitis and chronic periodontitis are found worldwide and are among the most prevalent microbial diseases of mankind. The cause of these common inflammatory conditions is the complex microbiota found as dental plaque, a complex microbial biofilm. Despite 3000 years of history demonstrating the influence of oral status on general health, it is only in recent decades that the association between periodontal diseases and systemic conditions such as coronary heart disease and stroke, and a higher risk of preterm low birth-weight babies, has been realised. Similarly, recognition of the threats posed by periodontal diseases to individuals with chronic diseases such as diabetes, respiratory diseases and osteoporosis is relatively recent. Despite these epidemiological associations, the mechanisms for the various relationships remain unknown. Nevertheless, a number of hypotheses have been postulated, including common susceptibility, systemic inflammation with increased circulating cytokines and mediators, direct infection and cross-reactivity or molecular mimicry between bacterial antigens and self-antigens. With respect to the latter, cross-reactive antibodies and T-cells between self heat-shock proteins (HSPs) and Porphyromonas gingivalis GroEL have been demonstrated in the peripheral blood of patients with atherosclerosis as well as in the atherosclerotic plaques themselves. In addition, P. gingivalis infection has been shown to enhance the development and progression of atherosclerosis in apoE-deficient mice. From these data, it is clear that oral infection may represent a significant risk-factor for systemic diseases, and hence the control of oral disease is essential in the prevention and management of these systemic conditions.

We have shown previously that both humoral and cellular immune responses to heat shock protein 60 (HSP60) are elevated in chronic periodontitis patients compared with non-diseased subjects. The aim of the present study was to determine whether periodontal treatment could influence the level of serum antibodies to human HSP60 and Porphyromonas gingivalis GroEL, a bacterial homologue of human HSP60. Sera were obtained from 21 patients with moderate to advanced chronic periodontitis at the baseline examination and again after completion of treatment. Antibody levels were determined using an enzyme-linked immunosorbent assay. The mean anti-P. gingivalis GroEL antibody levels were down-regulated significantly by periodontal treatment when recombinant P. gingivalis GroEL was used as an antigen, whereas antibody levels to P. gingivalis GroEL-specific peptide were significantly elevated following successful periodontal therapy. The mean level of anti-human HSP60 antibody remained unchanged although individual levels of antibody either increased or decreased after periodontal treatment, suggesting that synthesis of these antibodies might be regulated independently during the course of periodontal infection. Although their regulatory mechanisms in chronic infection are not understood, further study would provide insight not only into the role of these antibodies in the pathogenesis of periodontitis but also into the possible link between periodontitis and systemic diseases such as coronary heart disease.

T cell cytokine profiles and specific serum antibody levels in five groups of BALB/c mice immunized with saline alone, viable Fusobacterium nucleatum ATCC 25586, viable Porphyromonas gingivalis ATCC 33277, F. nucleatum followed by P. gingivalis and P. gingivalis followed by F. nucleatum were determined. Splenic CD4 and CD8 cells were examined for intracytoplasmic interleukin (IL)-4, interferon (IFN)-gamma and IL-10 by dual colour flow cytometry and the levels of serum anti-F. nucleatum and anti-P. gingivalis antibodies determined by an ELISA. Both Th1 and Th2 responses were demonstrated by all groups, and while there were slightly lower percentages of cytokine positive T cells in mice injected with F. nucleatum alone compared with the other groups immunized with bacteria, F. nucleatum had no effect on the T cell production of cytokines induced by P. gingivalis in the two groups immunized with both organisms. However, the percentages of cytokine positive CD8 cells were generally significantly higher than those of the CD4 cells. Mice immunized with F. nucleatum alone had high levels of serum anti-F. nucleatum antibodies with very low levels of P. gingivalis antibodies, whereas mice injected with P. gingivalis alone produced anti-P. gingivalis antibodies predominantly. Although the levels of anti-F. nucleatum antibodies in mice injected with F. nucleatum followed by P. gingivalis were the same as in mice immunized with F. nucleatum alone, antibody levels to P. gingivalis were very low. In contrast, mice injected with P. gingivalis followed by F. nucleatum produced equal levels of both anti-P. gingivalis and anti-F. nucleatum antibodies, although at lower levels than the other three groups immunized with bacteria, respectively. Anti-Actinobacillus actinomycetemcomitans, Bacteroides forsythus and Prevotella intermedia serum antibody levels were also determined and found to be negligible. In conclusion, F. nucleatum immunization does not affect the splenic T cell cytokine response to P. gingivalis. However, F. nucleatum immunization prior to that of P. gingivalis almost completely inhibited the production of anti-P. gingivalis antibodies while P. gingivalis injection before F. nucleatum demonstrated a partial inhibitory effect by P. gingivalis on antibody production to F. nucleatum. The significance of these results with respect to human periodontal disease is difficult to determine. However, they may explain in part differing responses to P. gingivalis in different individuals who may or may not have had prior exposure to F. nucleatum. Finally, the results suggested that P. gingivalis and F. nucleatum do not induce the production of cross-reactive antibodies to other oral microorganisms.

Heat shock protein 60s (hsp60) are remarkably immunogenic, and both T-cell and antibody responses to hsp60 have been reported in various inflammatory conditions. To clarify the role of hsp60 in T-cell responses in periodontitis, we examined the proliferative response of peripheral blood mononuclear cells (PBMC), as well as the cytokine profile and T-cell clonality, for periodontitis patients and controls following stimulation with recombinant human hsp60 and Porphyromonas gingivalis GroEL. To confirm the infiltration of hsp60-reactive T-cell clones into periodontitis lesions, nucleotide sequences within complementarity-determining region 3 of the T-cell receptor (TCR) beta-chain were compared between hsp60-reactive peripheral blood T cells and periodontitis lesion-infiltrating T cells. Periodontitis patients demonstrated significantly higher proliferative responses of PBMC to human hsp60, but not to P. gingivalis GroEL, than control subjects. The response was inhibited by anti-major histocompatibility complex class II antibodies. Analysis of the nucleotide sequences of the TCR demonstrated that human hsp60-reactive T-cell clones and periodontitis lesion-infiltrating T cells have the same receptors, suggesting that hsp60-reactive T cells accumulate in periodontitis lesions. Analysis of the cytokine profile demonstrated that hsp60-reactive PBMC produced significant levels of gamma interferon (IFN-gamma) in periodontitis patients, whereas P. gingivalis GroEL did not induce any skewing toward a type1 or type2 cytokine profile. In control subjects no significant expression of IFN-gamma or interleukin 4 was induced. These results suggest that periodontitis patients have human hsp60-reactive T cells with a type 1 cytokine profile in their peripheral blood T-cell pools.

Oropharyngeal candidiasis is associated with defects in cell-mediated immunity and is commonly seen in human immunodeficiency virus positive individuals and AIDS patients. A model for oral candidiasis in T-cell-deficient BALB/c and CBA/CaH nu/nu mice was established. After inoculation with 10(8) Candida albicans yeasts, these mice displayed increased levels of oral colonization compared to euthymic control mice and developed a chronic oropharyngeal infection. Histopathological examination of nu/nu oral tissues revealed extensive hyphae penetrating the epithelium, with polymorphonuclear leukocyte microabscess formation. Adoptive transfer of either naive or immune lymphocytes into immunodeficient mice resulted in the recovery of these animals from the oral infection. Reconstitution of immunodeficient mice with naive CD4(+) but not CD8(+) T cells significantly decreased oral colonization compared to controls. Interleukin-12 and gamma interferon were detected in the draining lymph nodes of immunodeficient mice following reconstitution with naive lymphocytes. This study demonstrates the direct requirement for T lymphocytes in recovery from oral candidiasis and suggests that this is associated with the production of cytokines by CD4(+) T helper cells.

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-beta1-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-alpha, 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-beta 1, TNF-alpha, IFN-gamma, 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.

It is now 35 years since Brandtzaeg and Kraus (1965) published their seminal work entitled "Autoimmunity and periodontal disease". Initially, this work led to the concept that destructive periodontitis was a localized hypersensitivity reaction involving immune complex formation within the tissues. In 1970, Ivanyi and Lehner highlighted a possible role for cell-mediated immunity, which stimulated a flurry of activity centered on the role of lymphokines such as osteoclast-activating factor (OAF), macrophage-activating factor (MAF), macrophage migration inhibition factor (MIF), and myriad others. In the late 1970s and early 1980s, attention focused on the role of polymorphonuclear neutrophils, and it was thought that periodontal destruction occurred as a series of acute exacerbations. As well, at this stage doubt was being cast on the concept that there was a neutrophil chemotactic defect in periodontitis patients. Once it was realized that neutrophils were primarily protective and that severe periodontal destruction occurred in the absence of these cells, attention swung back to the role of lymphocytes and in particular the regulatory role of T-cells. By this time in the early 1990s, while the roles of interleukin (IL)-1, prostaglandin (PG) E(2), and metalloproteinases as the destructive mediators in periodontal disease were largely understood, the control and regulation of these cytokines remained controversial. With the widespread acceptance of the Th1/Th2 paradigm, the regulatory role of T-cells became the main focus of attention. Two apparently conflicting theories have emerged. One is based on direct observations of human lesions, while the other is based on animal model experiments and the inability to demonstrate IL-4 mRNA in gingival extracts. As part of the "Controversy" series, this review is intended to stimulate debate and hence may appear in some places provocative. In this context, this review will present the case that destructive periodontitis is due to the nature of the lymphocytic infiltrate and is not due to periodic acute exacerbations, nor is it due to the so-called virulence factors of putative periodontal pathogens.

The purpose of this study was to identify the cell populations involved in recovery from oral infections with Candida albicans. Monoclonal antibodies specific for CD4+ cells, CD8+ cells, and polymorphonuclear leukocytes were used to deplete BALB/c and CBA/CaH mice of the relevant cell populations in systemic circulation. Monocytes were inactivated with the cytotoxic chemical carrageenan. Mice were infected with 10(8) C. albicans yeast cells and monitored for 21 days. Systemic depletion of CD4+ and CD8+ T lymphocytes alone did not increase the severity of oral infection compared to that of controls. Oral colonization persisted in animals treated with head and neck irradiation and depleted of CD4+ T cells, whereas infections in animals that received head and neck irradiation alone or irradiation and anti-CD8 antibody cleared the infection in a comparable fashion. The depletion of polymorphonuclear cells and the cytotoxic inactivation of mononuclear phagocytes significantly increased the severity of oral infection in both BALB/c and CBA/CaH mice. High levels of interleukin 12 (IL-12) and gamma interferon (IFN-gamma) were produced by lymphocytes from the draining lymph nodes of recovering animals, whereas IL-6, tumor necrosis factor alpha, and IFN-gamma were detected in the oral mucosae of both naïve and infected mice. The results indicate that recovery from oropharyngeal candidiasis in this model is dependent on CD4+-T-cell augmentation of monocyte and neutrophil functions exerted by Th1-type cytokines such as IL-12 and IFN-gamma.

An immunoperoxidase technique was used to examine IP-10 (interferon-gamma inducible protein 10), RANTES (regulated on activation normal T cell expressed and secreted), MCP-1 (monocyte chemoattractant protein-1), and MIP-1 alpha (macrophage inflammatory protein-1 alpha) in gingival biopsies from 21 healthy/gingivitis and 26 periodontitis subjects. The samples were placed into 3 groups according to the size of infiltrate. MIP-1 alpha+ cells were more abundant than the other chemokines with few MCP-1+ cells. The mean percent MIP-1 alpha+ cells was higher than the percent MCP-1+ cells (P = 0.02) in group 2 (intermediate size infiltrates) lesions from periodontitis subjects, other differences not being significant due to the large variations between tissue samples. Analysis of positive cells in relation to CD4/CD8 ratios showed that with an increased proportion of CD8+ cells, the mean percent MIP-1 alpha+ cells was significantly higher in comparison with the mean percent RANTES+ and MCP-1+ cells (P < 0.015). Endothelial cells were MCP-1+ although positive capillaries were found on the periphery of infiltrates only. Keratinocyte expression of chemokines was weak and while the numbers of healthy/gingivitis and periodontitis tissue sections positive for IP-10, RANTES and MCP-1 reduced with increasing inflammation, those positive for MIP-1 alpha remained constant for all groups. In conclusion, fewer leucocytes expressed MCP-1 in gingival tissue sections, however, the percent MIP-1 alpha+ cells was increased particularly in tissues with increased proportions of CD8 cells and B cells with increasing inflammation and also in tissues with higher numbers of macrophages with little inflammation. Further studies are required to determine the significance of MIP-1 alpha in periodontal disease.

The aim of this study was to evaluate clinically three commercially available dentifrices and to determine any surface effects on tooth or gingival surfaces. Sixty-four participants were included in this study and were allocated randomly to one of four treatment groups by an independent person to ensure the investigators were unaware of the brushing material used. All toothbrushes and dentifrices were distributed by this independent person. The treatment groups were: Group 1--brush with water; Group 2--brush with Colgate (Baking Soda and Peroxide); Group 3--brush with Macleans (Whitening); Group 4--brush with Colgate (Sensation Whitening). All participants were requested to brush both morning and evening in their customary fashion using only the designated toothpaste, or water, for four weeks. All participants were required to use the same toothbrush type. No other oral hygiene products such as mouth rinses or dental floss were used during the trial period. Prior to commencement of the brushing period, all participants received a full clinical examination recording the status of the soft and hard tissues including a gingival index (Löe and Silness) to record gingival condition. A polyvinyl siloxane impression was taken of the six anterior teeth and gingival tissues at the commencement of the trial. After four weeks, a second full clinical examination was made and further silicone impressions were taken of the anterior teeth. All impressions were cast in epoxy resin for investigation with light and electron microscopy. Participants were also asked to answer a questionnaire relating to the toothpaste used. The results of this study indicated that no significant clinical differences were recorded for any dentifrice or water and there was no significant difference in gingival index scores over the four week period. Patient responses to each dentifrice varied according to individual patient preferences and expectations and no consistent findings could be determined. Light and electron microscopy indicated that tooth and gingival surface changes that occurred over the four week period with any of the dentifrices were similar to, and not significantly different from, changes seen with the use of water alone. These results indicate that none of the dentifrices tested was harmful to teeth or soft tissues.

Chronic inflammatory periodontal diseases are characterized by a cellular infiltrate and are similar in many respects to other chronic inflammatory diseases. While periodontopathic bacteria have been recognized as the principal causative agent and the immune response to these bacteria is thought to be responsible for the tissue destruction, the full aetiological spectrum is still incompletely understood. In addition to many cell types such as polymorphonuclear leucocytes and macrophages, T cells have been implicated in pathogenesis and are considered to have regulatory roles in progression of the disease. Based on our recent studies demonstrating biased expression of several Vbeta families in periodontitis tissues, the aim of this study was to characterize further the T cells relevant to the disease process by reverse transcription-polymerase chain reaction-single-strand conformation polymorphism (RT-PCR-SSCP) and subsequent nucleotide sequence analysis of complementarity-determining region 3 (CDR3) of the TCR beta-chain. In spite of the likely involvement of numerous bacteria, the present study has clearly shown the oligoclonality of infiltrating T cells in periodontitis lesions in contrast to low clonality of peripheral blood T cells as evidenced by the appearance of distinct bands in gingival tissue samples and smear pattern of peripheral blood on SSCP gels. These were confirmed by the DNA sequencing of the CDR3 of Vbeta16 of selected samples. The analysis of deduced amino acid sequences demonstrated amino acid motifs in the CDR3 region of the periodontitis lesion-derived sequences from each patient. The results indicate that gingival tissue-infiltrating T cells recognizing a limited number of antigens or epitopes are involved in the disease process.

Data from CPITN studies indicate that severe periodontitis affects approximately 10 per cent of most populations. These data have remained static for a number of years. Of interest, however, is that despite the dramatic increase in the use of oral hygiene aids, efforts by the dental profession in oral hygiene instruction, and the associated general improvement in oral hygiene levels in the community, the incidence of severe chronic inflammatory periodontal disease has remained largely unaffected. The effects of changing oral hygiene may be reflected in slight shifts in the mild and moderate classifications of periodontal disease but the prevalence of advanced disease in presumably susceptible subjects has remained relatively unchanged. The ramifications of relatively non-specific plaque control measures in the management of advanced disease in susceptible subjects are still unclear and it may not be until the adoption of a more specific approach to the control of specific pathogens which inhabit the subgingival biofilm that major changes in the general incidence of the severe inflammatory periodontal diseases will be seen.

In the treatment of periodontal disease initial therapy aims at reducing marginal inflammation so allowing assessment of residual disease and further treatment options. The aim of the present study was to determine whether the use of a dentifrice and oral rinse containing sanguinaria extract led to a more rapid resolution of gingival inflammation following initial therapy. Thirty-four subjects, randomly assigned to one of two treatment groups, took part in this randomized double-blind parallel study. All subjects received initial therapy including oral hygiene instruction and scaling and root planing as required. One group also received an active dentifrice and oral rinse containing sanguinaria extract (an antiplaque agent) and zinc chloride. The other group received a placebo dentifrice and oral rinse. The gingival index (GI), plaque index (PLI) and probing pocket depths (PD) were recorded at six sites per tooth at baseline, two weeks after initial therapy and six weeks after initial therapy. There was no significant difference between the groups for any of the parameters at the baseline examination. Two weeks following initial therapy both groups showed a statistically significant increase in the number of sites with PLI of 0 or 1 (p < 0.0001) and a statistically significant increase in the number of sites with a GI of 0 or 1 (that is, no bleeding on probing), (p < 0.0001). Also there was a statistically significant increase in the number of sites with probing depths < or = 3 mm (p < 0.0001) compared with baseline. These changes were maintained through to six weeks post therapy. There was no significant advantage to the sanguinaria group. Results demonstrate that initial therapy in the form of oral hygiene instruction, scaling and root planing leads to a significant improvement in periodontal status which is maintained at least in the short term. Further, use of a dentifrice and oral rinse containing sanguinaria did not improve the efficacy of initial therapy.

The aim of the present study was to investigate the hypothesis that there is selective activation and expansion of a limited repertoire of T cell receptor (TCR)-bearing T cells in periodontitis tissue. We studied TCR V beta gene expression in gingival tissues of periodontitis lesions and compared these with peripheral blood mononuclear cells (PBMC) from the same patients using polymerase chain reaction (PCR) amplification with 22 V beta-specific sense primers in combination with a common antisense C beta-specific primer. After initial therapy, gingival tissue specimens were obtained from 14 periodontitis patients at the time of periodontal surgery, and PBMC were also obtained from the same patients by density gradient centrifugation. Total RNA was extracted and analysed by reverse transcription PCR. The PCR products were electrophoresed on a 2% agarose gel and stained with ethidium bromide. For each product, gingival tissue and the respective peripheral blood were compared. The TCR repertoire identified in the PBMC in general overlapped with that of the gingival tissue. However, V beta 6 appeared to be over-expressed in the gingival tissues compared with the PBMC, but V beta 16 appeared to be under-expressed in the gingival tissues. Although it is not known whether this is due to antigen-specific activation or superantigen activation, the data suggest that there may be as yet uncharacterized T cell subsets in periodontal disease tissue.

Microscope endoscopy is a technique which allows high resolution, non-invasive examination of soft tissues. This study employed microscope endoscopy to examine the process of healing following exposure of the oral mucosa to carbon dioxide laser radiation. On the wound boundaries, cellular debris and the laser-induced char layer were shed as epithelial migration occurred. Wounds healed by secondary intention, with complete epithelial closure by 72 hours. A marked vascular response was evident from 6 to 48 hours following wounding, a time period coincident with the known pattern of blood vessel activation and infiltration of the wound site by leukocytes. The use of microscope endoscopy as an adjunct to biopsy and other invasive diagnostic methods in the assessment and follow-up of soft tissue pathology may have value in clinical practice.

T cells are central to the immune response to infection and studies have indicated a local immunoregulatory imbalance may exist in human periodontal disease. Since Porphyromonas gingivalis is generally recognized as a major periodontopathogen, the aim of this study was to establish T cell lines and clones specific to P. gingivalis from the gingival tissues and peripheral blood of P. gingivalis--infected subjects. Two subjects were selected from two groups of individuals (one from each group) established on the basis of P. gingivalis in their plaque and the presence of serum antibodies which react with P. gingivalis antigens. The two groups differed however in their clinical susceptibility (adult periodontitis) or resistance (gingivitis) to periodontal breakdown. The mean ages +/- standard error of the mean of the two groups were 47.9 +/- 2.2 and 49.6 +/- 3.7, respectively, so that resistance in the gingivitis group was related to the age of the subjects. T cell lines and clones were established from the peripheral blood of one patient from each of the two groups and also from the gingival tissues of the same periodontitis subject. This study has demonstrated the capability of establishing P. gingivalis-specific T cell lines and clones from P. gingivalis-infected subjects and FACS analysis of the T cell receptor variable regions demonstrated that the clones were indeed monoclonal. The CD4:CD8 ratios of the peripheral blood-derived T cell lines were 1.2 and 0.4 for the gingivitis-derived line and the periodontitis-derived line, respectively, thus supporting the clinical differences displayed by the two subjects.

Microbiological and serological (enzyme linked immunosorbent assay) investigations were carried out, including karyotyping, on two Asian children with Papillon-Lefèvre syndrome. In case 1, a girl aged four years, the most prevalent putative periodontopathogens were Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia (deciduous dentition) and Bacteroides gracilis, E corrodens and F nucleatum (permanent dentition). In case 2, a boy aged nine years, they were F nucleatum, P intermedia and P loeschii and E corrodens. Serum from case 2 showed a raised specific IgG antibody response to Actinomyces actino-mycetemcomitans serotype b. Thus, a wider range of species than hitherto reported may be associated with Papillon-Lefèvre syndrome, including A actino-mycetemcomitans and F nucleatum.

T cell induced differentiation of B cells has been shown to be dependent on the CD2/LFA-3 and LFA-1/ICAM-1 pathways. Flow cytometric analysis was used to examine these adhesion molecules on T and B cells extracted from gingival tissues before and after stimulation with the putative periodontopathic bacteria, Porphyromonas gingivalis and Fusobacterium nucleatum. Adhesion molecule expression on peripheral blood cells from healthy adults was used as a control. Approximately 50 per cent of B cells extracted from gingival tissues expressed LFA-3 and ICAM-1 compared with 30 per cent positive peripheral blood B cells. Around 50 per cent of gingival T cells expressed CD2 relative to 76 per cent positive peripheral blood T cells. However, 40-50 per cent of both gingival and peripheral blood T cells expressed LFA-1. There was no difference in the expression of adhesion molecules on T and B cells extracted from health/marginal gingivitis or adult periodontitis lesions. After stimulation of gingival cells in vitro, the per cent CD2 positive T cells and LFA-3 and ICAM-1 positive B cells remained relatively stable over the six-day culture period, although P. gingivalis and F. nucleatum appeared to induce an increase in the percentage of gingival T cells expressing LFA-1. In contrast to the gingival lymphocytes, stimulation of peripheral blood cells resulted in an increase in the per cent CD2 positive T cells, LFA-3 and ICAM-1 positive B cells, with a decrease in LFA-1 positive T cells. The results therefore demonstrated that gingival T and B cells express adhesion molecules in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal models have been used to study the pathogenic ability of putative periodontopathic bacteria. Injection of mice with live Porphyromonas gingivalis extracts has been shown to induce primary lesions which develop at the site of injection within one day and secondary lesions which develop at a distant site some 3-5 days later. These lesions are primarily polymorphonuclear cell (PMN) infiltrates. Recently, extensive data have shown that PMN activity may in part be controlled by T cells. Hence the aim of this report was to use the mouse model to determine the presence of T cells and macrophages in primary lesions in order to describe a baseline to be used for comparison in future studies.

Concepts of the immunopathogenesis of recurrent aphthous stomatitis (RAS) based on lesion histology suggest an early role for CD4+ T cells. Other in vitro studies show enhanced destruction of epithelial targets by peripheral blood mononuclear cells (PBMC) from RAS subjects. The present project aimed to extend these studies under conditions simulating the in vivo situation. Epithelial cells were cultured and induced to express class I and class II major histocompatibility complex (MHC) antigens with gamma interferon (gamma-IFN). Co-cultures with autologous PBMC showed evidence of specific destruction of epithelial targets in RAS patients when compared with a control group. Co-culture with CD4+ enriched cells also showed specific epithelial cell lysis. Effector cells pre-incubated with interleukin-2 (IL-2) did not produce increased destruction of epithelial cells. This study has supported previous work and identified an early role of CD4+ cells.

While the precise mechanism of tooth eruption remains unknown it has been established that for tooth eruption to occur a functioning dental follicle is essential and normal bone resorption is required. In the osteopetrotic microphthalmic (mi) mouse, teeth fail to erupt and development is affected. In the present study, an organ culture technique was established to culture successfully lower first molars from normal and affected mi mice so as to determine if developmental defects were intrinsic to the dental tissue or whether such defects were a result of local environmental factors. Tissue was cultured for up to 13 days and development assessed morphologically at varying time intervals using standard light microscopy. Teeth developed similarly in both animal groups studied. The only variation in the appearance of cultured tissue occurred in the cervical loop region with more curling evident in dental tissue from the affected animals. The results of this study therefore showed that dental tissue from both normal and affected mi mice can be cultured for up to 13 days and that there is no difference in their development. It would appear that these teeth have the same ability to develop and consequently erupt, however the local environment influences tooth development and alters the eruption potential.

In recent years, the phenotypic characterization of T cell subsets has given way to a functional dichotomy based essentially on their cytokine profiles. In this context, the CD4+ helper T cell subset has been shown to consist of two types, termed Th1 and Th2. In general, Th1 cells produce interleukin (IL)-2 and interferon (IFN)-gamma, while Th2 cells characteristically produce IL-4, IL-5, and IL-6. The major function of the Th1 subset is to mediate delayed-type hypersensitivity reactions and their secondary function is suppression of B cell activity. In contrast, the major function of the Th2 subset is to provide B cell help, while their secondary function is cell-mediated immune suppression. A similar dichotomy has also been described for CD8+ T cells. The role that these functional T cell subsets and their cytokines play in terms of their protective and nonprotective outcomes in a variety of infectious and oral diseases is reviewed.

Attendance compliance of patients presenting for periodontal therapy during one calendar year at two practice locations (Perth, Western Australia and Darwin, Northern Territory) was observed over a period of three to four years, depending on whether the patients were seen in the earlier or latter part of the initial year. Both venues (full-time practice and visiting practice every quarter) gave very similar results, of around 10 per cent of patients who dropped out after initial consultation, without commencing treatment. As well, both venues showed a similar trend of subsequent patient 'attrition' after the initial phase of treatment, with the retention of approximately 40 per cent of the original group of patients after three to four years. Of these, a very high proportion (90 per cent) were totally compliant with maintenance recall appointments.

Proto-oncogenes are important in both normal cellular differentiation and in carcinogenesis. The majority of transforming genes belong to the ras family and the ras gene product has been shown to be elevated in some oral carcinomas. RAP-5 monoclonal antibody was used to determine the expression of the p21ras protein in normal and neoplastic oral mucosa in an immunohistological study. The expression of p21ras protein was generally restricted to acanthous cells with strong staining in normal oral mucosa and well-differentiated carcinomas. In contrast, the p21ras protein was not detected in significant amounts in severely dysplastic lesions and poorly differentiated carcinomas. These results suggest that expression of p21ras is a normal feature of more fully differentiated tissues, both normal and neoplastic, and is not useful as an indicator of cell proliferation or 'malignant potential'.

Limit dilution analysis (LDA) was used to determine the presence and frequency of periodontopathic-bacteria-specific T cells in the peripheral blood of patients with chronic inflammatory periodontal disease. Twelve adult periodontitis (AP), 13 marginal gingivitis (MG) and 12 healthy control subjects took part in the study. Bacteroides gingivalis and Actinomyces viscosus were used as test organisms, while tetanus toxoid was used as the control antigen. The median PTL-p frequencies to B. gingivalis were 46.33 x 10(-6), 45.33 x 10(-6) and 58.83 x 10(-6) in the control, gingivitis and AP groups respectively, while the median PTL-p frequencies to A. viscosus were 13.8 x 10(-6), 17.33 x 10(-6) and 11.5 x 10(-6), again in the control, gingivitis and AP groups. There were no statistically significant differences between the groups. All subjects displayed 'single-hit' kinetics with the control tetanus toxoid antigen and, with three exceptions, 'single-hit' kinetics was also found with the two test organisms. One control subject displayed a 'saw-tooth' curve with A. viscosus and a 'suppressor' curve with B. gingivalis, while two MG subjects had a 'saw-tooth' curve with B. gingivalis. These complex curves suggest that, in some subjects, more than one limiting cell type may exist in the cultures. Nevertheless, the results of the present study illustrate that lymphocytes specific to periodontopathic bacteria exist in the peripheral blood of both diseased and non-diseased subjects.