Overview

This observational study aims to examine the relationship between cigarette smoking and the levels of two proteins, mitofusin-1 (MFN1) and NLRP3, in the fluid found between the teeth and gums. These proteins are involved in processes related to cell function and inflammation.

Adults aged 25-65 years will be included in four groups: periodontally healthy nonsmokers, periodontally healthy smokers, nonsmokers with periodontitis, and smokers with periodontitis. Periodontitis is a gum disease that damages the tissues and bone supporting the teeth.

Participants will provide information about their health and smoking history and undergo a periodontal examination. Small samples of fluid from around the gums will be collected using paper strips before periodontal treatment. The samples will be analyzed for MFN1 and NLRP3.

Researchers will compare the amounts of these proteins across the four groups and examine their relationships with periodontal measurements and smoking history. No experimental medication or treatment will be assigned. Participants with periodontitis will be offered routine periodontal care after sample collection.

Eligibility

Inclusion Criteria:

• Aged 18-65 years. At least 20 natural teeth. For the periodontal health groups: periodontal health on an intact periodontium, with probing depths ≤3 mm, full-mouth bleeding on probing \<10%, and no interdental clinical attachment loss or radiographic bone loss attributable to periodontitis.

For the periodontitis groups: Stage III or Stage IV periodontitis according to the 2017 periodontal disease classification.

For the smoking groups: current cigarette smoking of at least 10 cigarettes per day for at least 5 years.

For the nonsmoking groups: fewer than 100 cigarettes smoked during the lifetime and no current use of tobacco or nicotine products.

Provision of written informed consent.

Exclusion Criteria:

• ormer cigarette smoking. Use of electronic cigarettes, heated tobacco products, nicotine pouches, or nicotine replacement products.

Uncontrolled diabetes, immunodeficiency, autoimmune or chronic inflammatory disease, or a serious systemic disease that may affect periodontal or mitochondrial responses.

Pregnancy or breastfeeding. Use of antibiotics, systemic corticosteroids, immunosuppressive medications, or regular anti-inflammatory medications within the previous 3 months.

Periodontal treatment within the previous 6 months. Acute oral infection, periodontal abscess, or local pathology affecting the sampling sites.

Gingival crevicular fluid samples contaminated with blood or saliva, or insufficient for ELISA analysis.