Ultrasonographic Assessment of the Effects of Platelet Rich Fibrin on Wound Healing Following Palatal Connective Tissue Harvesting.

This study was planned as a randomized prospective controlled study. Patients with Miller class 1 or 2 gingival recession who needs root coverage surgery in the Department of Periodontology were included in the study. The subepithelial connective tissue graft was obtained in each patient using the single incision technique from the region between the mesial of canine and the mesial of first molar in the palate. Connective tissue dimensions were approximately 10 × 5 × 2 mm. Finally, the incision line was sutured with 5/0 synthetic, nonabsorbable, sterile monofilament suture in the control group while L-PRF membrane was placed to the donor site in the test group before the suturing. Patients were evaluated using an ultrasonography device (MyLab™ Seven, Esaote, Genoa, Italy) at the Department of Oral and Maxillofacial Radiology. USG measurements were performed on days 0, 3, 7, 14, 21, 30 and 90 for palatal tissue thickness and tissue vascularization by an oral and maxillofacial radiologist with at least six years of experience. A 6-18 MHz intraoral probe was used in intraoral USG examinations. Sterile gel was applied to the intraoral probe and covered with a stretch film. Then, it was placed directly on the mucosal surface of the donor site in the palatal area. Mucosal thickness was evaluated using the B-mode of the device, and vascularization was evaluated using the color doppler and pulsed wave doppler modes of the device. The mean pulsatility index (PI) values of each patient were calculated and considered for statistical analysis.

The power analyse of the study was performed for sample size calculation. Sample size was calculated using a statistical program (G*Power; Universitat, Dusseldorf, Germany) for α = 0.05 and effect size = 0.26. The analyses revealed that 10 subjects per group achieved a power of 80 % with 95% confidence.

The data were analysed with the SPSS 21 program (SPSS Inc., Chicago, IL). Continuous variables were presented as mean ± standard deviation and categorical variables as numbers and percentages. Shapiro-Wilk test was used to detect data's normality. For the comparison of the parameters of the study groups, independent samples T-test test was used for normally distributed data while Mann Whitney U test test was performed as non-parametric test. Within-group comparisons between the different time periods were tested with repeated measures of ANOVA. Bonferroni correction was performed for multiple variations. The statistical significance value was accepted as p < 0.05.