Blinding and calibration
The reproducibility of the masked clinical examiner (REF) was assessed by measuring the recessions of four patients who were not included in the study at two different visits that were separated by at least 24 h. The data were used to determine the intraclass correlation coefficient, which was considered acceptable at values of at least 0.75.In addition, to determine the surgical technique to be used, the patients were randomized in blocks of four using a statistical software (IBM SPSS® Statistics 20.0;IBM, Chicago, IL, USA) [