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International audience; BACKGROUND: Disadvantaged migrant populations face risk factors that can affect their oral health amongst other health issues. The purpose of this study was to explore the oral care needs of these populations and to identify the obstacles they might encounter in accessing dental care. METHODS: A cross-sectional study using secondary data was carried out in the Centre Médical Louis Guilloux in Rennes, France, a health centre offering dental consults to migrants. The data were obtained by clinical oral examination and analysed according to various criteria: reason for consultation, diagnosis, treatment plan, drug prescriptions, and referrals to other practitioners. RESULTS: A high prevalence of decay was observed amongst the patients (72.3%). Fifty-nine patients were identified as needing major oral health care amongst the 130 files that were analysed. The lack of proficiency in the host country’s language was associated with a major need for oral care (P < .02). CONCLUSIONS: This study highlights that disadvantaged migrants face important oral care needs in France. It suggests alternative actions that should be carried out to improve their access to dental care, including access to interpreting.

Background: Porphyromonas gingivalis strain W83, one of the most widely investigated, is considered virulent in the context of periodontitis. The recently isolated P. gingivalis TDC60 has been reported to be highly pathogenic, although it has not yet been investigated in a mouse periodontitis model by oral gavage. Aim: Our aim was to compare the virulence of both strains by evaluating their impact on alveolar bone loss and the composition of oral microbiota. Methods: We inoculated by oral gavage C57BL/6 mice with either one of the two P. gingivalis strains and compared to a sham-treated group, without antibiotics pre-treatment. The mandibular alveolar bone of treated mice and controls were assessed, one month after the final inoculation, by microCT measurements. Moreover, at this time, we characterized their oral microbiota by 16S rRNA gene sequencing. Results: While P. gingivalis W83 successfully initiated periodontitis, TDC60-treated mice only experienced moderate lesions. Furthermore, only W83-treated mice exhibited a specific distinct microbiota, with significantly lower richness and evenness than other samples, and decreased proportions of taxa usually found in healthy individuals. Conclusion: This association between alveolar bone loss and a major persistent shift of the oral microbiota gives insights into virulence discrepancies among these bacterial strains.

In the oral cavity, periodontal health relies on a balance between the subgingival bacterial community and the host’s immune function. The current pathophysiological model of chronic periodontitis shows a negative feedback loop that implies a dysbiotic microbiota and a dysregulation of the inflammatory response. As an increasing number of associations between the periodontal disease and systemic conditions are reported, this work describes how a genetic iron overload disease — HFE-related hereditary haemochromatosis — is likely to influence the host–microbiota interactions within the subgingival sulcus. We conducted clinical and microbiological cross-sectional studies, that showed transferrin saturation coefficient having an impact on the severity of periodontitis, probably related to the promotion of periodontal pathogenic species. However, morphometric analysis of the murine model for hereditary haemochromatosis Hfe(–/–) revealed alterations in the mandibular alveolar bone micro-architecture, suggesting a disruption of bone remodeling. A mixed animal model, with Porphyromonas gingivalis-induced periodontitis and Hfe(–/–) mice, was therefore performed, in order to explore the underlying mechanisms of the relationships between iron excess, bacterial dysbiosis, and periodontitis., Dans la cavité buccale, la santé parodontale repose sur un équilibre entre la communauté bactérienne sous-gingivale et la fonction immunitaire de l’hôte, toutes deux compatibles avec un état sain. Le modèle pathophysiologique actuel de la parodontite chronique montre un cercle vicieux entre un microbiote dysbiotique et une dérégulation de la réponse inflammatoire. Alors qu’un nombre croissant d’associations entre maladie parodontale et pathologie systémique sont rapportées, ce travail décrit comment une maladie génétique de surcharge en fer — l’hémochromatose héréditaire liée au gène HFE — est susceptible d’influencer l’équilibre hôte–microbiote au sein du sillon sous-gingival. Les études transversales, clinique et microbiologique, que nous avons menées, ont ainsi montré un impact du coefficient de saturation de la transferrine sur la sévérité de la parodontite, probablement en lien avec la sélection d’espèces pathogènes pour le parodonte. Cependant, l’analyse morphométrique du modèle murin de l’hémochromatose héréditaire Hfe(–/–) a révélé des altérations de la micro-architecture de l’os alvéolaire mandibulaire, suggérant un dérèglement du remodelage osseux. Un croisement entre deux modèles animaux, parodontite induite par Porphyromonas gingivalis et Hfe(–/–), a donc été mis en œuvre, afin d’explorer les mécanismes de cette association entre excès de fer, dysbiose bactérienne et parodontite.

International audience; Genetic haemochromatosis (GH) is responsible for iron overload. Increased transferrin saturation (TSAT) has been associated with severe periodontitis, which is a chronic inflammatory disease affecting tissues surrounding the teeth and is related to dysbiosis of the subgingival microbiota. Because iron is essential for bacterial pathogens, alterations in iron homeostasis can drive dysbiosis. To unravel the relationships between serum iron biomarkers and the subgingival microbiota, we analysed samples from 66 GH patients. The co-occurrence analysis of the microbiota showed very different patterns according to TSAT. Healthy and periopathogenic bacterial clusters were found to compete in patients with normal TSAT (≤45%). However, significant correlations were found between TSAT and the proportions of Porphyromonas and Treponema, which are two genera that contain well-known periopathogenic species. In patients with high TSAT, the bacterial clusters exhibited no mutual exclusion. Increased iron bioavailability worsened periodontitis and promoted periopathogenic bacteria, such as Treponema. The radical changes in host-bacteria relationships and bacterial co-occurrence patterns according to the TSAT level also suggested a shift in the bacterial iron supply from transferrin to NTBI when TSAT exceeded 45%. Taken together, these results indicate that iron bioavailability in biological fluids is part of the equilibrium between the host and its microbiota.

International audience