Salivary Mitofusin-1 Levels in Periodontitis: Associations With Disease Severity, Smoking, and Treatment Response

Inclusion criteria

• Willing and able to provide written informed consent.
• Systemically healthy (no history of diabetes mellitus, immunodeficiency, malignancy, or other systemic conditions that could affect periodontal status).
• Have a minimum of 20 natural teeth (excluding third molars).
• No antibiotic therapy or periodontal treatment in the last 6 months.

For Healthy Control Group:

No clinical attachment loss. Probing depth ≤ 3 mm. No radiographic evidence of bone loss. Low gingival and plaque index scores.

For Mild Periodontitis Group:

Diagnosed with Stage I or II periodontitis according to the 2018 AAP/EFP classification.

Clinical attachment loss of 1-4 mm. Radiographic bone loss of ≤15-33%. Non-smoker.

For Severe Periodontitis Group:

Diagnosed with Stage III or IV periodontitis according to the 2018 AAP/EFP classification.

Clinical attachment loss ≥ 5 mm. Radiographic bone loss to the mid-advanced level of the root. Non-smoker.

For Severe Periodontitis with Smoking Group:

Meets all criteria for the Severe Periodontitis Group. Regular smoker (at least 10 cigarettes per day for a minimum of 5 years).

Exclusion criteria

• Fewer than 20 natural teeth (excluding third molars).
• Presence of any systemic disease (e.g., diabetes mellitus, immunological disorders, cancer).
• Use of antibiotics or receiving periodontal treatment in the last 6 months.
• Pregnancy or lactation.
• For non-periodontitis groups (Healthy Control): Any signs of periodontitis.
• For periodontitis groups (all): History of smoking cessation for at least 5 years (must be either a current regular smoker or a never-smoker, depending on the group definition).