The outbreak of Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has significantly affected the dental care sector. Dental professionals are at high risk of being infected, and therefore transmitting SARS-CoV-2, due to the nature of their profession, with close proximity to the patient’s oropharyngeal and nasal regions and the use of aerosol-generating procedures. The aim of this article is to provide an update on different issues regarding SARS-CoV-2 and COVID-19 that may be relevant for dentists. Members of the French National College of Oral Biology Lecturers (“Collège National des EnseignantS en Biologie Orale”; CNESBO-COVID19 Task Force) answered seventy-two questions related to various topics, including epidemiology, virology, immunology, diagnosis and testing, SARS-CoV-2 transmission and oral cavity, COVID-19 clinical presentation, current treatment options, vaccine strategies, as well as infection prevention and control in dental practice. The questions were selected based on their relevance for dental practitioners. Authors independently extracted and gathered scientific data related to COVID-19, SARS-CoV-2 and the specific topics using scientific databases. With this review, the dental practitioners will have a general overview of the COVID-19 pandemic and its impact on their practice.

As antibiotic pressure often triggers bacterial resistance, the use of short-duration therapies is increasingly recommended. The objective of the present study was to evaluate both the clinical efficiency and the impact on oral streptococci of a 3 day versus a 7 day amoxicillin therapy for odontogenic infection requiring tooth extraction. On day 0, patients were randomly assigned to a 3 day or 7 day amoxicillin treatment. The tooth was extracted on day 2 and the post-operative follow-up was carried out on day 9. Oral flora was collected on days 0, 9 and 30, and the susceptibility of the streptococci to amoxicillin was determined. The results showed that treatment with amoxicillin for 3 or 7 days had a similar clinical efficiency, and also induced similar selection of oral streptococci with reduced susceptibility to amoxicillin, suggesting that the selection of strains with reduced susceptibility to amoxicillin is a rapid phenomenon, appearing even with short-duration therapies.

Neisseria meningitidis is a Gram-negative bacterium which is an important causative agent of septicaemia and meningitis. LuxS has been shown to be involved in the biosynthesis of a quorum sensing molecule, autoinducer-2 (AI-2), known to play a role in virulence in Escherichia coli, as well as other bacteria. Evidence that serogroup B of N. meningitidis produces AI-2, along with the observation that a luxS mutant of this strain had attenuated virulence in an infant rat model of bacteraemia, led to further investigation of the role of this quorum sensing molecule in N. meningitidis. In this study, it is demonstrated that AI-2 is not involved in regulating growth of meningococci, either in culture or in contact with epithelial cells. Furthermore, transcriptional profiling using DNA microarrays shows an absence of the concerted regulation seen in other bacteria. Taken together, these data suggest that in N. meningitidis, AI-2 may be a metabolic by-product and not a cell-to-cell signalling molecule.

The type IV pili (Tfp) of Neisseria meningitidis play an essential role in meningococcal virulence by mediating the initial interaction of bacteria with host cells. Tfp are also subject to retraction, which relies on the PilT protein. Among the other components of the Tfp machinery, PilC1, a pilus-associated protein, is important for Tfp biogenesis and adhesion. Adhesion of N. meningitidis to living epithelial cells was previously shown to rely on the upregulation of the pilC1 gene. On the other hand the lack of induction of pilC1 is believed to be responsible for the low adhesion of N. meningitidis onto fixed dead cells. Surprisingly, a pilT mutant, unable to retract its pili, has been shown to adhere very efficiently onto both living and fixed epithelial cells. To elucidate the mechanisms by which the pilus retraction machinery mediates meningococcal adhesion onto fixed cells, an analysis of gene expression levels in wild-type and pilT meningococci was performed using DNA microarrays. One of the upregulated genes in the pilT strain was pilC1. This result was confirmed using quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) and immunoblot analysis. The transcription starting point responsible for the upregulation of pilC1 in a pilT background was shown to be different from those controlling the induction of pilC1 upon contact with living host cells. Subsequent work using a strain hyperproducing PilT confirmed that PilT downregulates the production of PilC1. Furthermore using a pilC1 allele under the control of IPTG, we demonstrated that the upregulation of pilC1 in a pilT background was responsible for the adhesive phenotype onto fixed dead cells. Taken together our results demonstrate that the pilus retraction machinery negatively controlled the adhesiveness of the Tfp via the expression of pilC1.

Background/Aims Contact sports such as handball may lead to orofacial injuries that can often be prevented by the use of a properly fitted mouthguard. Several studies have investigated orofacial injuries during contact sports in different countries, but there is a lack of data that is specific for French handball players. Therefore, the aims of this study were to determine the prevalence of orofacial injuries and the proportion of handball players using a mouthguard in Eastern France. Material and Methods Data were collected from handball players aged over 15 years old from five handball clubs in the Lorraine Region (Eastern France). A questionnaire containing 26 questions about the general characteristics of participants, orofacial injury experiences, emergency procedures following tooth avulsion, and use of mouthguards was self‐administered. Results Two hundred and sixty‐three handball players, of which 76.8% (202) were males, aged 23 ± 8 years on average, with a mean playing experience of 11 ± 6 years, participated in the study. Among them, 24.7% (65) reported at least one orofacial injury. A total of 237 orofacial injuries was declared. The main types of orofacial injuries including lip, cheek and tongue injuries were reported by 18.6% of handball players (49); dental injuries were reported by 9.9% (26) and injuries to the temporomandibular joint were reported by 4.9% (13). Most participants knew about mouthguards (97.3%, 254) and considered them efficient for preventing dental injuries in handball (95.3%, 242/254), but only 3.0% (8) used them. Conclusion The prevalence of orofacial injuries among French handball players was high while mouthguards were very rarely used. Information should be provided to handball teams regarding mouthguard use and the management of dental injuries.

Atmospheric CO concentrations increased significantly over the last century and continuing increases are expected to have significant effects on current ecosystems. This study evaluated the behavioural and physiological (hormone status, muscle structure) effects of prolonged CO exposure in young female Wistar rats exposed at 700ppm of CO during 6h a day for 15days. Prolonged CO exposure, though not continuous, produced significant disturbances in behaviour with an increase in drinking, grooming and resting, and a reduction in rearing, jumping-play and locomotor activity. Furthermore, CO exposure was accompanied by increased plasma levels of corticosterone, suggesting that prolonged exposure to CO was stressful. The muscular structure can also be modified also when respiratory working conditions change. The expression of myosin heavy chain was significantly affected in the diaphragm and oral respiratory muscles: Masseter Superficialis and Anterior Digastric. Modified behaviour and hormonal changes both appear to be at the origin of the observed muscular adaptation.

No abstract

INTRODUCTION: Barometric pressure variation during dives may induce barodontalgia and barotrauma. Barodontalgia refers to oral pain resulting from a change in ambient pressure. The aim of this study was to investigate the occurrence of barodontalgia and dental barotrauma among French civilian scuba divers.METHODS: A nationwide cross-sectional internet-based survey was conducted among French scuba divers over 18 yr of age registered by the French Federation of Underwater Sports (FFESSM). The online questionnaire was distributed from October to December 2020. It contained questions regarding general characteristics of participants, barodontalgia and dental barotrauma occurrences, and relationship of the diver with his/her dentist.RESULTS: There were 684 scuba divers (65.4% men; aged 48 ± 12 yr) who participated in the study. Barodontalgia was reported by 18.7%, with some respondents reporting more than one episode. Most barodontalgia affected posterior (81.2%) and upper teeth (55.2%) with dental filling (50.0%). At least one dental barotrauma was reported by 10.1% of respondents, including mainly loss or fracture of a dental filling (4.2%). The occurrence of dental barotrauma was significantly higher among men (12.3%) than women (5.9%) and increased significantly with the age, the years of diving and the diving qualification.CONCLUSION: Information should be provided to divers on the importance of routine dental checkups.Kougeon K, Yasukawa K, Baudet A. Barodontalgia and dental barotrauma among scuba divers. Aerosp Med Hum Perform. 2022; 93(5):421–425.