Abstract:

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<0.01), the changes of G+and G-were more obvious in the test group till week 1(P<0.05). The total CFUof test group diminished significantly just after laser irradiation (P<0.05). That revealed the laser therapy followed by SRP appeared to have a stronger effect on converting the subgingival micro-ecosystem to healthy status. Conclusion　Laser appeared to have a stronger bactericidal actionin vivo,especially on the dark-pigmented G-rods associated with periodontal disease.

Key words: pulsed Nd:YAG laser, periodontal disease, ultrasonic subgingival scaling and root planning