Mean PPD and BOP values were , 6 and 12 months after implant placement , 2.74 0.49 mm ( 95 % CI 2.51 to 2.97 ) and 1.28 0.75 ( 95 % CI 0.93 to 1.63 ) in the RP group , and 2.70 0.38 mm ( 95 % CI 2.53 to 2.88 ) and 1.39 0.78 ( 95 % CI 1.03 to 1.75 ) in the PS group respectively , with no statistical differences between groups ( P = 0.81 and P = 0.16 , respectively ) .