Abstract: Abstract: Objective To evaluate the curative effects of diode laser on the treatment for moderate to severe chronic periodontitis.Methods This is a randomized,single blind clinical trial.Dentitions of 10 severe chronic periodontitis patients were randomly divided into experiment group and control group.There were two sites with probing depth (PD) ≥6 mm in each quadrant and 80 in all.At the first visit,supragingival scaling was performed.Two weeks later,each site in experimental group was treated with scaling and root planing (SRP）and diode laser (980 nm 2 W) irradiation for 30s,while those in control group were treated with SRP only.The changes of PD,clinical attachment loss (CAL) and bleeding on probing (BOP) were recorded and compared before treatment and 3 months after treatment.Results Before treatment,there were no significant differences in clinical indicators between two groups (P>0.05).3 months later,all clinical indexes decreased significantly in both groups (P<0.05) compared with those before treatment.In experimental group,PD was （4.15±0.24）mm,CAL was（5.45±0.28）mm，and positive rate of BOP was 20% while in control group,PD was（4.13±0.28）mm，CAL was（5.15±0.30）mm，and positive rate of BOP was 42.5%.In addition,in experimental group,positive rate of BOP decreased significantly compared with that in control group (P<0.05),but at the levels of PD and CAL,there were no significant differences between these two groups (P>0.05).Conclusions Diode laser is an effective adjuvant treatment for moderate to severe chronic periodontitis in short term,and its long-erm efficacy needs further study.

Key words: diode laser, moderate to severe chronic periodontitis, initial therapy