The Effectiveness of Root Planing and Injectable Platelet-Rich Fibrin in Smoking Patients With Periodontitis

Periodontitis is a chronic, multifactorial inflammatory disease characterized by the progressive destruction of tooth-supporting tissues associated with dysbiotic plaque biofilms. The loss of periodontal support manifests clinically as attachment loss, alveolar bone loss, periodontal pocket formation, and gingival bleeding. Due to its high prevalence, potential to cause tooth loss, negative impact on chewing function and esthetics, and reduction in quality of life, periodontitis is considered a significant public health concern. The primary etiological factor of the disease is microbial plaque and its byproducts.

The goal of periodontal treatment is to halt disease progression by controlling the microbial etiology and associated risk factors and to restore lost periodontal structures, thus maintaining a functional and esthetically acceptable dentition. Various treatment modalities have been developed to reduce bacterial plaque on root surfaces. Conventional methods include mechanical plaque removal using hand instruments and ultrasonic devices, with scaling and root planing considered the gold standard in periodontal therapy.

Adjunctive use of local agents with root surface debridement has shown additional benefits. These agents help reduce bacterial contamination and promote healing. Local antimicrobial agents suppress subgingival microbiota and support the control of inflammation. Other materials, such as hyaluronic acid and statins, have also demonstrated beneficial clinical outcomes when used in conjunction with non-surgical periodontal therapy.

Smoking is a major risk factor both for the onset of periodontitis and for a reduced treatment response. Smokers tend to exhibit less favorable healing after non-surgical treatments and experience greater tooth loss over time. Additionally, smoking can result in exposed root surfaces and protected areas that facilitate plaque accumulation, contributing to disease recurrence.

Platelets have gained attention in regenerative therapies due to their ease of collection and their rich content of growth factors. Platelet-derived factors such as TGF-β1 exhibit both pro- and anti-inflammatory properties. Platelets become activated following endothelial injury and, through various adhesion molecules, initiate inflammatory responses and support tissue repair. They also play a key role in hemostasis and wound healing by stimulating fibroblast, endothelial, and progenitor cell activity through their released growth factors.

Platelet concentrates are classified into two generations: first-generation platelet-rich plasma (PRP) and second-generation platelet-rich fibrin (PRF). PRP preparation is complex, requiring additives and multiple centrifugation steps, and its clinical effect is limited by the rapid release of growth factors. PRF, in contrast, is a fully autologous product obtained by simple centrifugation of venous blood without additives. A variation known as injectable PRF (I-PRF), prepared at lower speeds and shorter durations, contains not only platelets and leukocytes but also stem and endothelial cells, thus being referred to as a "blood concentrate."

I-PRF has been shown to release higher levels of growth factors, enhance fibroblast migration, and increase the expression of collagen and regenerative cytokines. Additionally, I-PRF demonstrates stronger antimicrobial activity against periodontal pathogens compared to other platelet concentrates.

A total of 25 volunteers will be included in the study. Inclusion criteria are: not pregnant, no use of antibiotics, anti-inflammatory drugs, or systemic corticosteroids, no periodontal treatment in the past 6 months, presence of at least 20 teeth, bleeding on probing in ≥30% of sites, and at least two non-adjacent teeth in each quadrant with probing depth ≥5 mm, clinical attachment loss ≥4 mm, and radiographic evidence of bone loss in the coronal third (horizontal and/or vertical). Informed consent will be obtained after explaining the study.

Eligible participants will undergo clinical periodontal evaluation including plaque index (Silness \& Löe, 1964), gingival index (Löe \& Silness, 1963), probing depth, clinical attachment loss, and bleeding on probing (Ainamo \& Bay, 1975). At the second visit, full-mouth scaling and root planing will be performed. In the test sites, injectable platelet-rich fibrin (I-PRF), prepared by centrifugation at 700 rpm for 3 minutes, will be applied. Control sites will receive saline without antimicrobial or regenerative effects. Follow-ups for oral hygiene reinforcement will be scheduled at 1 week, 1 month, and 3 months. Clinical measurements will be repeated at 3 months.

The aim of this study is to evaluate the clinical effects (plaque index, gingival index, bleeding on probing, probing pocket depth, and clinical attachment level) of adjunctive injectable platelet-rich fibrin application in non-surgical periodontal therapy in periodontitis patients with deep pockets who smoke.