Investigators hypothesize that in patients with obstructive sleep apnea (OSA) the severity of periodontal disease is significantly higher compared to patients without OSA in every aspect, including PI, PD, CAL and BOP. The number of lost teeth is hypothesized to be also higher in patients with obstructive sleep apnea.

Purpose: evaluation of periodontal status in patients with obstructive sleep apnea.

An analytical cross-sectional study will be conducted at the Department of Therapeutic Dentistry of the Sechenov University, Moscow.

Investigators are planning to recruit 100 patients: 1) patients with OSA confirmed by polysomnography -75 participants aged between 35 and 65; 2) patients without OSA -25 participants of a similar age.

Patients with obstructive sleep apnea syndrome will be sub-divided into three sub-groups according to OSA severity: 2A group - patients with mild apnea severity; 2B group - patients with medium apnea severity; 2C group - patients with severe apnea.

All participants will undergo a dental examination including the following parameters: plaque index (PI; Silness & Loe, 1964), bleeding on probing (BOP), and touch depth of the pocket (PD), the level of clinical attachment loss (CAL). Investigators will also evaluate the number of lost teeth.

Periodontal disease is a chronic inflammatory disease which is associated with an increased risk of many diseases, including bone and cardiovascular disease (Adamkiewicz et al., 2018). The high prevalence and severity of periodontal inflammatory diseases is a current problem in dentistry. A growing body of literature suggests that there is a link between periodontitis and systemic diseases. Nevertheless a cause-and-effect relationship has not been established yet for most of the diseases, and the mediators of the association are still being identified (Bui et al., 2019). In recent years, several studies have revealed a possible link between periodontitis and obstructive sleep apnea (OSA). The main oral symptom of OSA is dry mouth due to oral breathing, which is a significant risk factor for periodontal disease. Chronic periodontitis is characterized by the destruction of the supporting tissues of the teeth through complex cascades of inflammatory responses, and OSA seems to share common pathways, acting synergistically (Ryan Price et al., 2020).

The purpose of the study is to evaluate the periodontal health in patients with obstructive sleep apnea (OSA).

Within an analytical cross-sectional study 150 patients will be examined: 75 patients with obstructive sleep apnoea and 25 patients without OSA.

The diagnosis of sleep apnea will be set after the standard polysomnography in the Domino program. The severity of OSA will be determined according to AHI index.

Patients with obstructive sleep apnea syndrome will be sub-divided into three groups according to sleep apnea severity: 2A group - patients with mild sleep apnea severity; 2B group - patients with medium sleep apnea severity; 3С group - patients with severe sleep apnea.

After confirming the diagnosis of obstructive sleep apnea patients undergo dental examination. Investigators will use a manual periodontal probe to provide basic periodontal examination.

The amount of plaque accumulated in cervical part of the teeth will be registered by the plaque index (PI; Silness & Loe, 1964). The activity of the inflammation will be assessed with use of Bleeding on probing index (BOP). The Pocket Touch Depth (PD) will and the level of clinical attachment loss (CAL) will be recorded. The number of lost teeth will also be estimated.

Potential risk factors for periodontal disease will also be evaluated (body weight index (BMI), smoker status).

Inclusion Criteria:

Patients with obstructive sleep apnea

Exclusion Criteria:

Pregnancy and lactation diabetes mellitus coronary heart disease medications associated with xerostomia chronic infectious diseases.

Patients of the Somnology Center, healthy volunteers recruited from Sechenov University staff.