After 6 months , both techniques allowed for the excellent mean root coverage of 96.3 plus/minus 12.1 % in the control group and of 91.3 plus/minus 17.6 % in the test group.Complete root coverage was achieved in 89.5 % ( 17/19 ) and 79 % ( 15/19 ) of the recession cases in the control and the test groups respectively .