Efficacy of inorganic bovine bone combined with leukocyte and platelet-rich fibrin or collagen membranes for treating unfavorable periodontal infrabony defects: Randomized non-inferiority trial

Background: Growing evidence shows the efficacy of platelet concentrates in periodontal therapy. This study aimed to demonstrate that an inorganic bovine bone graft (IBB) in combination with a leukocyte and platelet rich fibrin (L-PRF) is non-inferior to a combination with a collagen membrane (CM) when managing unfavorable infrabony defects (IBDs). Methods: All patients exhibited at least one unfavorable IBD; they were randomly assigned to two groups, 31 treated with L-PRF+IBB and 31 with CM+IBB. A clinical and radiographic examination was performed at baseline and 12 months later. Clinical attachment level (CAL), gingival recession (GR), probing depth (PD), and radiographic defect bone level (DBL) post-therapy changes were compared between the two treatments. A non-inferiority margin = 1 mm was set to determine the efficacy of the test treatment (‒1 mm for GR); a second non-inferiority margin = 0.5 mm (‒0.5 mm for GR) was chosen for clinical relevance. Results: Twelve months after surgery a significant improvement of clinical and radiographic parameters was observed at both experimental sites. The 90% confidence intervals of the CM+IBB‒L-PRF+IBB mean difference for CAL gain (‒0.810 mm [‒1.300 to ‒0.319]) and DBL gain (‒0.648 mm [‒1.244 to ‒0.052]) were below the 0.5 mm non-inferiority margin; GR increase (1.284 mm [0.764 to 1.804]) remained above the ‒0.5 mm, while PD reduction (0.499 mm [0.145 to 0.853]) crossed its 0.5-mm margin. Conclusions: The L-PRF+IBB treatment of unfavorable IBDs offers non-inferior efficacy for CAL gain, showing less GR and more DBL gain too, while for PD reduction it is inferior to the CM+IBB treatment.