<qa>  What was the name of the group that was assigned to the patient?The participants were randomly assigned to receive coronally advanced flap CAF with amnion chorion membrane or CAF with subepithelial connective tissue graft using a simple randomization procedure with a 1:1 allocation ratio. A computer generated randomization list was drawn up by a faculty member who was not involved in the recruitment. Allocation concealment was achieved by sealed coded opaque envelopes that contained the treatment to be performed to the enrolled subjects based on the randomized numbers. Consequently, patients were allocated to either AC membrane intervention or SCTG control groups. The sealed envelope containing treatment assignment was opened at time of the surgery and the number was picked by another person other than the operator. 