Oral viridans group streptococci are the major commensal bacteria of the supragingival oral biofilm and have been detected in human atheromatous plaque. Atherosclerosis involves an ongoing inflammatory response, reportedly involving chronic infection caused by multiple pathogens. The aim of this study was to examine the invasion of human aortic endothelial cells (HAECs) by oral viridans group streptococci and the subsequent cytokine production by viable invaded HAECs. The invasion of HAECs by bacteria was examined using antibiotic protection assays and was visualized by confocal scanning laser microscopy. The inhibitory effects of catalase and cytochalasin D on the invasion of HAECs were also examined. The production of cytokines by invaded or infected HAECs was determined using enzyme-linked immunosorbent assays, and a real-time polymerase chain reaction method was used to evaluate the expression of cytokine messenger RNA. The oral streptococci tested were capable of invading HAECs. The number of invasive bacteria increased with the length of the co-culture period. After a certain co-culture period, some organisms were cytotoxic to the HAECs. Catalase and cytochalasin D inhibited the invasion of HAECs by the organism. HAECs invaded by Streptococcus mutans Xc, Streptococcus gordonii DL1 (Challis), Streptococcus gordonii ATCC 10558 and Streptococcus salivarius ATCC 13419 produced more cytokine(s) (interleukin-6, interleukin-8, monocyte chemoattractant protein-1) than non-invaded HAECs. The HAECs invaded by S. mutans Xc produced the largest amounts of cytokines, and the messenger RNA expression of cytokines by invaded HAECs increased markedly compared with that by non-invaded HAECs. These results suggest that oral streptococci may participate in the pathogenesis of atherosclerosis.

Objectives:The aim of this study is to investigate the prevalence and severity of gingival inflammation and associated risk indicators in South American adults.Material and Methods:Multi-stage samples totaling 1,650 adults from Porto Alegre (Brazil), Tucumán (Argentina), and Santiago (Chile) were assessed. The sampling procedure consisted of a 4-stage process. Examinations were performed in mobile dental units by calibrated examiners. A multivariable logistic regression model was utilized for associating variables as indicators of gingival inflammation (GI) (Gingival Index ≥0.5). Statistical significance was set at 0.05.Results:A total of 96.5% of the adults have GI. Regarding the severity of GI, 22.5% of participants examined have mild GI, 74.0% have moderate GI, and 3.6% have severe GI. The multivariate analyses identify the main risk indicators for GI as adults with higher mean of Calculus Index (OR=18.59); with a Visible Plaque Index ≥30% (OR=14.56); living in Santiago (OR=7.17); having ≤12 years of schooling (OR=2.18), and females (OR=1.93).Conclusions:This study shows a high prevalence and severity of gingival inflammation, being the first one performed in adult populations in three cities of South America.

The isolation frequencies of opportunistic bacteria and fungi increase during orthodontic treatment, suggesting the importance of paying special attention to oral hygiene in orthodontic patients to prevent periodontal disease and the aggravation of systemic disease in immunocompromised conditions.

The aims of this study were to describe the self-reported oral hygiene habits, dental visit frequency, and gingival bleeding perception in adult populations from three South American cities, and also to assess the association of these variables with sociodemographic data and with the clinical presence of plaque and gingival inflammation. Five-hundred and fifty adult subjects from each city (Porto Alegre, Brazil; Tucumán, Argentina; Santiago, Chile) received full mouth examinations to determine visible plaque and gingival index. A structured questionnaire on demographics, habits, attitudes and knowledge of oral health was also administered. The data were analyzed according to dental visit frequency, toothbrushing frequency, interproximal tooth cleaning frequency, subjects' perception of gum bleeding, and proportion of subject sites with VP and bleeding sites. Analysis of the association among the variables was performed using either a chi-square test or Fischer's exact test. Toothbrushing twice a day or more was reported by 84.2% of the subjects, but only 17.7% reported daily interdental cleaning, and 60.2% reported visiting a dental clinic only in an emergency. Only 2.97% had no bleeding sites, whereas 33.7% had 50% or more bleeding sites. Regular interdental self-cleaning and a dental visit every 3-6 months was associated with less plaque and less gingival bleeding. More than 12 years of education was associated with healthier habits, less bleeding and plaque scores. In conclusion, the oral health behavior of South American adult subjects from these cities is below the international recommendations, especially in relation to interdental cleaning and regular dental visits.

Summary Streptococcus oralis, belonging to the oral viridans group streptococci, has been detected in human cardiovascular lesions including infective endocarditis and atheromatous plaques. The organism has coaggregation receptor polysaccharides (RPS) on the cell wall, which function as receptors for surface adhesins on other members of the oral biofilm community. The present study examined the capacity of S. oralis RPS to induce inflammatory responses in human aortic endothelial cells (HAECs). Purified RPS was used to stimulate HAECs, and the induction of cytokines, adhesion molecules and Toll‐like receptors (TLRs) was examined. Involvement of RPS in HAEC invasion by S. oralis was also examined. RPS‐stimulated HAECs produced more cytokines (interleukin‐6, interleukin‐8 and monocyte chemoattractant protein‐1) and intercellular adhesion molecule‐1 than non‐stimulated HAECs. The messenger RNA (mRNA) expression of cytokines and adhesion molecules in RPS‐stimulated HAECs increased markedly compared with that in non‐stimulated HAECs. Upregulation of TLR‐2 mRNA expression was demonstrated in RPS‐stimulated HAECs. Moreover, TLR‐2 mRNA expression and cytokine production were reduced by the incubation of HAECs with inhibitors against p38 mitogen‐activated protein kinase and nuclear factor‐κB. An RPS‐defective mutant of S. oralis showed greater invasion into HAECs than an RPS‐possessing strain. However, HAECs invaded by the RPS‐defective mutant produced less cytokines than HAECs invaded by the RPS‐possessing strain, indicating that RPS can stimulate HAECs intracellularly. These results suggest that S. oralis RPS may be an important contributor to the pathogenesis of cardiovascular diseases such as infective endocarditis and atherosclerosis.