This cross-sectional observational study aims to evaluate the relationship between periodontal inflammation severity and the Pan-Immune-Inflammation Value (PIV) in systemically healthy adults. A total of 160 participants will be recruited from the Department of Periodontology, Faculty of Dentistry, Bolu Abant Izzet Baysal University. Clinical periodontal parameters and Periodontal Inflamed Surface Area (PISA) will be recorded, and their association with PIV calculated from complete blood count parameters will be analyzed.

Periodontitis is a chronic inflammatory disease that leads to progressive destruction of the tooth-supporting tissues and contributes to systemic inflammatory burden. Periodontal Inflamed Surface Area (PISA) is a validated quantitative measure that estimates the total inflamed periodontal surface area and reflects the inflammatory burden associated with periodontal disease.

The Pan-Immune-Inflammation Value (PIV) is a novel composite biomarker calculated from complete blood count parameters using the following formula: neutrophil count × platelet count × monocyte count / lymphocyte count. PIV has been proposed as a comprehensive indicator of systemic inflammation.

This cross-sectional observational study aims to investigate the relationship between PISA and PIV in systemically healthy adults.

A total of 160 participants aged 18 years and older will be recruited from the Department of Periodontology, Faculty of Dentistry, Bolu Abant Izzet Baysal University. Participants will be classified as periodontally healthy, gingivitis, or periodontitis according to the 2017 World Workshop Classification of Periodontal and Peri-Implant Diseases and Conditions.

Clinical periodontal parameters, including Plaque Index, Gingival Index, Papillary Bleeding Index, Probing Pocket Depth, Clinical Attachment Loss, Bleeding on Probing, and PISA, will be recorded by a single calibrated examiner.

Complete blood count results obtained within the previous three months will be used to calculate PIV.

The primary objective is to evaluate the association between PISA and PIV. Secondary objectives include assessing the relationships between PIV and other periodontal clinical parameters.

An a priori power analysis performed using G*Power indicated that at least 84 participants were required to detect a moderate correlation (r = 0.30) with 80% power at a significance level of 0.05. To allow subgroup analyses and potential exclusions, 160 participants will be enrolled.

Statistical analyses will be conducted using SPSS software, and statistical significance will be set at p < 0.05.

Inclusion Criteria:

• Age 18 years and older
• Systemically healthy individuals
• Complete blood count performed within the previous 3 months
• Diagnosis of periodontal health, gingivitis, or Stage III-IV periodontitis according to the 2017 World Workshop Classification of Periodontal and Peri-Implant Diseases and Conditions
• Willingness to provide written informed consent

Exclusion Criteria:

• Pregnancy or lactation- History of systemic diseases that may affect periodontal tissues
• Use of antibiotics or anti-inflammatory drugs within the previous 3 months
• Periodontal treatment within the previous 6 months
• Presence of infectious diseases such as HIV, hepatitis B, or tuberculosis

Systemically healthy adults aged 18 years and older who present to the Department of Periodontology, Faculty of Dentistry, Bolu Abant Izzet Baysal University, and who are diagnosed as periodontally healthy, having gingivitis, or having Stage III-IV periodontitis according to the 2017 World Workshop Classification of Periodontal and Peri-Implant Diseases and Conditions.

Individual participant data (IPD) will not be publicly shared to protect participant confidentiality. De-identified and aggregated data may be available from the corresponding author upon reasonable request.