Objective This study was to observe and compare the microbiological effects of laser therapy combined with ultrasonic subgingival scaling and root planning (SRP) versus SRP alone.Methods 26 contra lateral teeth were randomly as- signed to the test group (laser+SRP) or the control group (SRP alone). Subgingival microbial samples were collected,cultured and analyzed at baseline, then repeated immediately after laser treatment atweek 1,week 2 and week 4.Results Although both groups had significant increase in G+/G-ratio (P
