The following treatments were randomly applied ( for 60 seconds ) to implant sites on days 0 , 7 , and 14 : ( 1 ) air ( O2 ) and saline ( 0.9 % NaCl ) ( control group ) , ( 2 ) O2 and H2O2 ( 3 % ) , ( 3 ) O3 and saline , and ( 4 ) O3 and H2O2 .