Abstract: PURPOSE: The aim of this study was to evaluate the clinical efficacy and the level of DKK1 and alkaline phosphatase (ALP) activity in gingival crevicular fluid (GCF) while taking Er:YAG laser as an adjunctive to scaling and root planning in the treatment of chronic periodontitis (CP). METHODS: Eleven patients with CP were included and there were nineteen pairs of homonym teeth(thirty-eight teeth) in this split-mouth design, and they were randomly assigned to experimental group or control group. In the experimental group, a combination of ultrasonic subgingigval scaling and root planning with hand instrument (SRP) were performed with Er: YAG laser as an adjunctive; in the control group, only SRP was performed. The main variables were bleeding index (BI), probing depth (PD), clinical attachment loss (CAL) which were assessed at baseline (1 week after ultrasonic subgingival scaling), l month and 3 months after treatment. GCF was collected at baseline, l week, l month and 3 months, and the levels of DKK1 and ALP activity were detected at the same time point. The data were analyzed with SPSS 19.0 software package. RESULTS: Both groups showed significant reduction of PD, CAL, BI values 1 month and 3months after treatment, but no significant difference in clinical parameters were found between the two groups. In the experimental group, the activity of ALP reduced to (386.69±146.42), (341.221±171.62), (249.27±98.72) from (396.191±150.55) U/L and the level of DKK1 dropped to (310.34±184.68), (270.04±55.14), (247.31±56.99) from (307.12±45.63) μg/L at the end of 1 week, 1 month, 3 months, respectively. Meanwhile, in the control group, the activity of ALP reduced to (374.72±131.27), (344.42±127.80), (252.36±90.4 ) from (394.09±120.25) U/L and the level of DKK1 dropped to (310.34±84.68), (270.04±55.14), (247.31±56.99) from (305.33±147.40) μg/L at the end of l week, l month, 3months, respectively. There is no significant difference between the two groups at any period for ALP or DKK1. CONCLUSIONS: Er:YAG laser was a safe no-surgical adjunctive therapy in treating chronic periodontitis, further observation is needed to determine its long-term effectiveness.

Key words: Periodontitis, Er:YAG laser, Dickkopf-1, Alkaline phosphatase