Periodontitis is a chronic inflammatory disease that destroys the supporting tissues of the teeth and may also increase systemic inflammatory burden. Leukocyte- and platelet-rich fibrin (L-PRF) is an autologous blood-derived biomaterial widely used in periodontal and oral regenerative procedures because it contains platelets, leukocytes, growth factors, and a fibrin matrix that promotes wound healing and tissue regeneration.

The purpose of this study is to determine whether Stage III-IV generalized periodontitis affects the quality and quantity of L-PRF. L-PRF obtained from periodontally healthy individuals and patients with generalized Stage III-IV periodontitis will be compared by evaluating fibrin architecture, cellular composition, and the temporal release of growth factors. The findings are expected to improve understanding of whether systemic inflammatory changes associated with periodontitis influence the biological properties of L-PRF and its regenerative potential.

Leukocyte- and platelet-rich fibrin (L-PRF) is a second-generation autologous platelet concentrate that contains a dense fibrin matrix enriched with platelets, leukocytes, cytokines, and growth factors. Owing to its regenerative properties, L-PRF has become widely used in periodontal regeneration and oral surgery. Although periodontitis is associated with systemic inflammation and alterations in circulating immune cells and inflammatory mediators, its potential influence on the biological characteristics of L-PRF has not been adequately investigated.

The objective of this prospective case-control study is to evaluate the effect of Stage III-IV generalized periodontitis on the quality and quantity of L-PRF. Periodontally healthy individuals and patients diagnosed with Stage III-IV generalized periodontitis will be included. Venous blood samples will be collected to prepare L-PRF membranes. Complete blood count parameters will also be recorded.

L-PRF membranes will be analyzed using histological and immunohistochemical methods to evaluate fibrin architecture and the distribution of platelets, neutrophils, monocytes/macrophages, T lymphocytes, B lymphocytes, and stem cells within the fibrin matrix. In addition, the temporal release of PDGF-AB, VEGF, TGF-β1, and IGF-1 from L-PRF membranes will be quantified by enzyme-linked immunosorbent assay (ELISA) after 1 hour, 24 hours, 3 days, and 7 days of incubation.

The primary objective is to determine whether periodontitis-related systemic inflammation alters the structural and biological characteristics of L-PRF. The results of this study will provide novel information regarding the potential impact of periodontal inflammation on the regenerative capacity of L-PRF and may contribute to optimizing its clinical use in regenerative therapies.

Inclusion Criteria:

• Diagnosed as periodontally healthy or Stage III-IV generalized periodontitis according to the 2017 World Workshop Classification.
• Adults aged 30-50 years.
• Systemically healthy individuals.
• Non-smokers.
• Referred from the Department of Oral and Maxillofacial Radiology to the Department of Periodontology due to periodontal disease.
• Willing and able to provide written informed consent and participate in the study.

Exclusion Criteria:

• Refusal or inability to provide informed consent or participate in the study.
• Presence of any systemic disease.
• Current smokers.
• Pregnancy or breastfeeding.
• Individuals with physical or psychological disabilities that may interfere with study participation.
• History of substance abuse.
• Severe malocclusion.
• Current orthodontic treatment, use of orthodontic appliances, or removable prostheses.
• Presence of acute dental pain or infection (e.g., dental caries, abscess, or acute odontogenic infection).
• History or presence of malignant disease.
• Participation in another clinical study at the time of enrollment.

The study population consists of systemically healthy, non-smoking adults aged 30-50 years who are referred to the Department of Periodontology, Faculty of Dentistry, Süleyman Demirel University, from the Department of Oral and Maxillofacial Radiology. Participants will be classified as either periodontally healthy or diagnosed with Stage III-IV generalized periodontitis according to the 2017 World Workshop Classification.