Need to improve understanding of oral dysbiosis in the elderly and/or immunocompromised individuals (involvement of nanogenes in these dysbiosis) Comparison of dysbiosis identification between results from dental plaque samples and saliva samples (the saliva sample is non-operator-dependent due to its ease of collection). Comparison of the reliability of results obtained with this type of saliva sample versus results obtained with dental plaque samples, which are considered the reference sample type (Antézack 2023).

Primary objective To estimate the prevalence of dysbiosis in individuals with oral frailty versus individuals without oral frailty.

In this project:

• Dysbiosis will be defined by the presence of Archaea (Bringuier 2013). For the primary objective, prevalence will be estimated based on dental plaque samples.
• The population with oral frailty will be defined as individuals over 60 years of age or those with immunosuppression.

Hypothesis: The expected proportion of dysbiosis in the population with oral health vulnerability is 40%, whereas the expected proportion of dysbiosis in the population without oral health vulnerability is 20% (Li CL 2009).

Secondary objectives Estimate the prevalence of dysbiosis in the two populations based on a saliva sample

- Compare the results from the sample

Study Design A cross-sectional case-control study. Participation in the study will be offered to all eligible subjects who meet the inclusion criteria.

Number of Patients 250 patients. For each patient, a dental plaque sample and a saliva sample will be collected during the visit.

Inclusion Criteria:

Case selection criteria:

Cases are defined as subjects with oral health vulnerability

• Men or women aged 60 years or older
• and/or immunocompromised individuals without periodontal disease (gingivitis, periodontitis, and peri-implantitis) clinically diagnosed by the dentist during the consultation.
• Patients who have received information about the study and have not expressed objection
• Patients who are beneficiaries or eligible for a social security program Control group selection criteria Controls are defined as subjects without oral health vulnerability • Men and women under 60 years of age without periodontal disease (gingivitis, periodontitis, and peri-implantitis) clinically diagnosed by the dentist during the consultation.

The clinical examination allows for the diagnosis of the absence or presence of periodontal disease, with particular attention to: bleeding on probing, the depth of periodontal pocket(s), tooth mobility, bone destruction in furcation areas, and the assessment of radiographic bone level taking age into account.

Exclusion Criteria:

• Patients who are currently excluded from another research protocol at the time the informed consent form is collected.
• Subjects covered by Articles L1121-5 through L1121-8 of the Public Health Code (minors, adults under guardianship or conservatorship, patients deprived of their liberty, pregnant or breastfeeding women),
• Men and women with periodontal disease (gingivitis, periodontitis, and peri-implantitis)
• Men and women with any systemic disease
• Men and women currently undergoing drug treatment