Update on B Cell Response in Periodontitis.

B cells have a central and dual role in the physio-pathological mechanisms of periodontitis. They take part in the elimination of the periodontal germs, the induction of tissue destructions and the regulation of the immune response. B cells play an essential role in the destruction of alveolar bone in periodontitis by immunomodulation, rather than by production of antibodies. In the periodontal cell network, B cells are in constant interaction with other immune cells and mesenchymal cells. Periodontitis is characterized by a cellular conversion from a dominant T-cell lesion to a dominant B-cell lesion, particularly enriched in plasma cells. This evolution results from abnormal interactions between B and T cells in periodontitis. Moreover, B cells are at the crossroads of the immune and the bone systems and are involved in the autoimmune mechanisms described in periodontitis. Different subsets of B cells are involved in periodontal destruction, in particular memory B cells, plasma cells and B1 cells. Effector memory B cells strongly express mRANKL in periodontitis and constitute the precursors of plasma cells. B1 cells are also involved in tissue destruction but also in the mechanisms of regulation, in particular via the natural secretion of IL-10 by CD11b+ B1 cells which form a part of the B10 cells that regulate the inflammatory response. As such, periodontitis seems to be associated with a deficit in regulation. In peripheral blood, B cells can also be systemic markers of infection and periodontal inflammation: circulating memory B cells are increased in periodontitis while circulating CD11b+ B1 cells are decreased. The study of B cells in periodontitis is constantly evolving for a better knowledge of the periodontitis setting, the evaluation and the follow-up of periodontitis, but also for the design of new therapeutic targets that may be promising in the management of severe periodontitis.

B cell subset distribution is altered in patients with severe periodontitis.

Several studies have recently highlighted the implication of B cells in physiopathogenesis of periodontal disease by showing that a B cell deficiency leads to improved periodontal parameters. However, the detailed profiles of circulating B cell subsets have not yet been investigated in patients with severe periodontitis (SP). We hypothesised that an abnormal distribution of B cell subsets could be detected in the blood of patients with severe periodontal lesions, as already reported for patients with chronic inflammatory diseases as systemic autoimmune diseases. Fifteen subjects with SP and 13 subjects without periodontitis, according to the definition proposed by the CDC periodontal disease surveillance work group, were enrolled in this pilot observational study. Two flow cytometry panels were designed to analyse the circulating B and B1 cell subset distribution in association with the RANKL expression. A significantly higher percentage of CD27+ memory B cells was observed in patients with SP. Among these CD27+ B cells, the proportion of the switched memory subset was significantly higher. At the same time, human B1 cells, which were previously associated with a regulatory function (CD20+CD69-CD43+CD27+CD11b+), decreased in SP patients. The RANKL expression increased in every B cell subset from the SP patients and was significantly greater in activated B cells than in the subjects without periodontitis. These preliminary results demonstrate the altered distribution of B cells in the context of severe periodontitis. Further investigations with a larger cohort of patients can elucidate if the analysis of the B cell compartment distribution can reflect the periodontal disease activity and be a reliable marker for its prognosis (clinical trial registration number: NCT02833285, B cell functions in periodontitis).

Pilot Study of Laser Doppler Measurement of Flow Variability in the Microcirculation of the Palatal Mucosa.

Background. Histopathological alterations can arise when the denture-supporting mucosa experiences microbial and mechanical stress through the denture base and diagnosis of these diseases usually follows microvascular changes. Microcirculation measurement could allow for detection of such dysfunction and aid in the early diagnosis of palatal mucosa pathologies. Materials and Methods. We tested the sensitivity of laser Doppler for measuring the microcirculation of the palatal mucosa, assessing the median raphe (MR), Schroeder area (SA), and retroincisive papilla (RP). A Doppler PeriFlux 5000 System, containing a laser diode, was used. 54 healthy participants were recruited. We compare the measurements of PU (perfusion unit) using ANOVA test. Results. The numerical values for palatal mucosa blood flow differed significantly among the anatomical areas (p = 0.0167). The mean value of Schroeder area was 92.6 (SD: 38.4) and was significantly higher than the retroincisive papilla (51.9) (SD: 20.2) (p < 0.05), which in turn was higher than that of median raphe (31.9) (SD: 24.2) (p < 0.0001). Conclusion. Schroeder area appeared to have the greatest sensitivity, and vascular flow variability among individuals was also greatest in this region. We suggest that analysis of blood stream modification with laser Doppler of the palatal mucosa can help to detect onset signs of pathological alterations.

Anti-B lymphocyte immunotherapy is associated with improvement of periodontal status in subjects with rheumatoid arthritis.

AIM: Rheumatoid arthritis (RA) and periodontitis present many similar features. The benefits of anti-B lymphocyte therapy (rituximab) on reducing tissue resorption in RA prompted us to assess its potential efficacy on the periodontal status of patients with RA treated with rituximab. MATERIALS AND METHODS: Periodontal status was assessed in 21 subjects with RA, divided into two groups: Group I consisted in 11 subjects assessed before their first infusion of rituximab and again 6 months later. Five of them were also assessed for up to 4 years after their first rituximab infusion. The 10 subjects in group II had received more than two courses of two rituximab infusions at the time of periodontal assessment. RESULTS: Pocket depth and attachment loss were significantly decreased 6 months after treatment with rituximab in group I. The periodontal status of the five subjects from group I followed for up to 48 months after rituximab treatment was improved irrespective of the clinical parameter observed. Patients from group II had a better periodontal status than patients from group I before treatment with rituximab. CONCLUSIONS: Anti-B lymphocyte therapy could be beneficial to improve periodontitis suggesting a major role of B cells in this disease.

[Dental care during pregnancy]. / Enquête sur la prise en charge de la femme enceinte au cabinet dentaire.

AIM: to understand and analyze knowledge and practices of dentists regarding dental care during pregnancy using a questionnaire which focuses on the knowledge of the relationship between oral infections and complications of pregnancy, the attitude of practitioners on the implementation of dental care during pregnancy and the training of practitioners. RESULTS: 53.9% of pregnant women are not referred by an obstetrician. Only 59.8% of practitioners believe that dental anesthesia is not contraindicated, and most practitioners believe that the best time for care is the second trimester or after pregnancy. During pregnancy, practitioners realize the motivation for hygiene (90.7%), drainage of an abscess (82.2%), scaling (76.1%), the placement of a splint (74.1%), the treatment of caries (70%), and the removable prosthesis (67.2%). CONCLUSION: these results indicate the existence of a gap between the care of pregnant women and the state of the art in dental science, despite current clinical recommendations to deliver all necessary care to pregnant patients during the first, second and third trimester. Moreover, the results highlight the need to reinforce the initial training of dental students, but also to develop the training for practitioners in this field.

Laser-induced fluorescence for subgingival calculus detection: scientific rational and clinical application in periodontology.

OBJECTIVE: To review the data available on the laser-induced calculus fluorescence phenomenon and the calculus detection devices as well as to determine the clinical relevance of using commercialized calculus detection devices in periodontal treatment. METHODS: In vitro or in vivo English publications found on Medline. RESULTS: In vitro and in vivo studies showed that the devices on the market had a satisfactory detection capacity. Very few studies demonstrated that the erbium:yttrium-aluminium-garnet (Er:YAG) laser debridement, when performed with automatic calculus detection, could lead to improvements at the clinical level, and the outcome was similar to that obtained with conventional treatments. CONCLUSIONS: Although preliminary data were encouraging, there was a lack of scientific data concerning the calculus detection devices. Therefore, future studies are crucial for determining the clinical relevance of such equipment.

[Update on side effects of alcohol-containing antiseptic mouthwashes]. / Mise à jour sur les effets secondaires de l'alcool dans les bains de bouches antiseptiques.

Antiseptic mouthwashes are widely prescribed in odontostomatology. Also, they are increasingly integrated in routine oral hygiene programs. Graded ethanol is present in many of the available mouthwashes. This has continuously raised the concern about their safety and potential side effects of the alcohol in their composition. Alcohol was associated in many reports to cancers of the oral and pharyngeal region. Xerostomia was also suggested as a potential side effect of alcohol-containing mouthwashes. Although substantial evidence supports the association of ethanol to oral cancer, the supposed association lacks of consistency and scientific evidence. Future research is needed to determine the causal relationship of alcohol-containing mouthwashes and oral cancers. On the other hand, the benefit of alcohol in mouthwashes composition is not scientifically established.