Title
Peri-implantitis surgical treatment with L-PRF: clinical cases.
 
Background: Peri-implantitis (PI) has been defined has the presence of radiographic bone loss (RBL)≥3mm and/or probing depth (PD)≥6mm and profuse bleeding on probing (BoP). There are no evidence made recommendation regarding surgical treatment of PI. Leucocyte-platelet rich fibrin (L-PRF) improves the recruitment and proliferation of a variety of cells like endothelial cells and osteoblasts. Clinical benefits at bone regeneration and osseointegration healing are confirmed by systematic reviews.

Aim: To present the 6 months clinical and radiographic results of peri-implantitis surgical treatment with L-PRF.

Material and Methods: Five patients (1 implant/patient) were diagnosed with PI (RBL≥3mm; PD≥6mm; BOP). Mucosal recession (MR), PD, BoP, clinical attachment level (CAL)) and periapical X-Ray (RBL) were taken at baseline. 
After venipuncture L-PRF membranes were prepared (Choukroun´s protocol). A mucoperiosteal flap was elevated and the presence of Cl Ie defects confirmed. The implant was rinsed with saline, calculus removed with a titanium curette (Deppeler®, Switzerland), and implant cleaned with an air-flow system/glycine (Perio-mate, NSK®, Japan). The peri-implant defects were totally filled and then covered with L-PRF membranes. Flaps were sutured. When possible implants were left submerged. Suture was removed after 10-15. At month 6 clinical and radiographic data were recorded.
Changes between 0 and 6 months were analyzed (Wilcoxon test).  Statistical analyses used SPSS v24 (SPSS Statistics for Windows, IBM). Significance level of P ≤ .05.

Results: Two weeks post-operative one implant was lost. The implants had 7.4±3.5 years in function. 
The baseline clinical data were PD=7.23±2.50mm; MR=0.00±0.00mm; BoP=90.00±20.00 and CAL=7.23±2.50mm. Regarding radiographic data RBL=4.38±0.77mm. 
At the 6 months evaluation PD=3.75±1.42mm; MR=0.00±0.00mm; BoP=16.67±0.00 and CAL=3.75±1.42mm. Regarding radiographic data RBL=5.86±1.21mm.  
The variation between 6-0 months (treatment effect) was PD-2.79 ± 1.38mm ([-4.99; -0.59], p=0.068); MR=0.00±0.00mm ([0.00; 0.00], p=1.000); BoP=-0.54 ± 0.28 ([-0.99; -0.09], p=0.068) and CAL=-2.79 ± 1.38mm ([-4.99; -0.59], p=0.068), RBL=-0.58 ± 0.99mm ([-2.16; 1.00], p=0.273).

Conclusion and Clinical implications: All peri-implant defects were circumferential Cl I e. This allowed to confine and stabilize the L-PRF membranes within the defect. This was also helped by the final membranes placed over the filled defect. The tested surgical treatment did not allowed to obtain clinical and radiographic statistical significant results, after a 6 months follow-up.   
Peri-implantitis surgical treatment with L-PRF seems not to have a positive treatment effect.

Peri-implantitis surgical treatment with L-PRF- clinical cases