Evaluation of Salivary Apelin, Chemerin, Ghrelin and Lipocalin 2 Levels in Diabetic Patients With Periodontitis

This observational cross-sectional study will be conducted at the Department of Periodontology, Faculty of Dentistry, Necmettin Erbakan University. The study will include individuals who apply to the periodontology clinic for various reasons, meet the eligibility criteria, and agree to participate by signing the informed consent form.

The study population will consist of 88 individuals aged 18-80 years. Participants will be allocated into four groups according to periodontal status and the presence or absence of type 2 diabetes mellitus: periodontally healthy and systemically healthy individuals, periodontally healthy individuals with type 2 diabetes mellitus, systemically healthy individuals with periodontitis, and individuals with both periodontitis and type 2 diabetes mellitus. Each group will include 22 participants.

Periodontal status will be determined by a calibrated specialist clinician based on clinical and radiographic examinations according to the 2017 World Workshop Classification of Periodontal and Peri-Implant Diseases and Conditions. Participants in the periodontitis groups will be required to meet the criteria for generalized Stage II or Stage III periodontitis. Periodontal clinical parameters, including probing depth, clinical attachment loss, bleeding on probing, gingival index, plaque index, gingival recession, tooth mobility, furcation involvement, and keratinized gingival width, will be recorded from six sites per tooth. Sociodemographic data, oral hygiene habits, and body mass index will also be recorded.

Unstimulated saliva samples will be collected before periodontal probing and before periodontal treatment in order to prevent possible contamination of saliva by bleeding during clinical measurements. Participants will be instructed not to brush their teeth and to avoid food, chewing gum, cosmetic products such as lipstick, and medications that may affect salivary measurements for at least one hour before sample collection. Saliva samples will be collected between 8:00 AM and 10:00 AM. After rinsing the mouth with water, saliva will be collected into plastic tubes using a glass funnel within five minutes. The samples will then be centrifuged at 1000 rpm for 10 minutes to remove cellular debris and plaque. The supernatant will be transferred into polypropylene Eppendorf tubes without disturbing the pellet and stored at -20°C until analysis.

On the day of analysis, samples will be thawed at +4°C. Salivary chemerin, ghrelin, apelin, and lipocalin-2 levels will be measured using enzyme-linked immunosorbent assay kits according to the manufacturer's instructions.