In this study, we compared low-power CO₂ laser treatment to ultrasonic scaling, which is generally approved as a power-driven mechanical instrumentation, and evaluated both of these treatments regarding their clinical effectiveness and change in the volume of in GCF.

20 patients who had gingivitis were selected. all of patients has no systemic problems. Randomly selected, one quadrant received ultrasonic scaling only, another quadrant received ultrasonic scaling and CO₂ laser irradiation, the other quadrant received CO₂ laser irradiation only. Clinical parameters measured at baseline, 1 weeks, 2weeks, 4weeks and 8weeks.

Pocket probing depth and clinical attachment level were not changed during study period. Gingival index of all group were improved after treatment. At 1 weeks after treatment, Gingival index of ultrasonic scaling group was only significantly different compared to control group. At 2 weeks after treatment, gingival index of all experimental group were significantly different compared to control group. At 4 and 8 weeks after treatment, gingival index of all group were increased, but experimental group were lower than control group. Sulcus bleeding index was similar to the results of gingival index. At 1 weeks after treatment, all experimental group were significantly different compared to control group and it maintained during study. At 2 weeks after treatment, sulcus bleeding index of all group were lowest during study. Gingival crevicular fluid were measured with Periotron® 8000(Oraflow®, Inc. USA). At baseline, all group were showed moderately severe condition. At 1 week after treatment, laser treatment only group was reduced quantity of gingival crevicular fluid mostly, and all group were reduced quantity of gingival crevicular fluid. At 2 weeks after treatment, all group were healty state. At 4 and 8 weeks after treament, all group were showed recurrent of inflammation, and control group was the most significantly increased.

This study showed that the effects of CO₂ laser treatment were similar to conventional ultrasonic scaling and this result remained longer than plaque control only. These results suggest possibility of CO₂ laser treatment for altered periodontal therapy.