A total of 76 patients with periodontitis and molar root bifurcation who were treated by periodontal regenerative surgery were selected as the subjects. They were divided into simple periodontal tissue regeneration group （control group） and Nd∶YAG laser irradiation-assisted periodontal tissue regeneration surgery group（experimental group）， with 38 cases in each group. The patients in two groups underwent conventional guided tissue regeneration， and the patients in experimental group received Nd∶YAG laser to treat the root bifurcation area during the operation. The periodontal probing depth （PPD）， vertical attachment loss （CAL-V）， horizontal attachment loss （CAL-H）， bleeding index （BI），and the horizontal penetration depth of root bifurcation （HPD） before surgery， 6 months after surgery and 12 months after surgery of the patients were compared between two groups； the values of vertical bone loss （BL-V） and horizontal bone loss （BL-H） were measured by cone beam CT （CBCT）.

There were no significant differencs in PPD， CAL-V， CAL-H， BI， BL-V and BL-H of the patients between two groups before surgery （P>0.05）；compared with before surgery，PPD， CAL-V， CAL-H， BI， HPD， BL-V， BL-H of the patients in two groups all showed a downward trend at 6 and 12 months after surgery； the above indicators in experimental group at 6 and 12 months after surgery were significantly lower than those in control group （P<0.05）. There was no statistical difference in the chewing efficiency of the patients between two groups before surgery （P>0.05）.Compared with before surgery， at 6 and 12 months after surgery， the chewing efficiencise of the patients in two groups had a increasing trend； the chewing efficiencies in experimenyal group were higher than those in control group at 6 and 12 months after surgery （P<0.01）.

In the periodontal regeneration surgical treatment of the patients with periodontitis and molar root bifurcation lesions， the use of Nd∶YAG laser adjuvant treatment can effectively enhance the treatment effect of periodontal regenerative surgery， reduce the periodontal inflammation，promote the periodontal tissue healing，and improve the chewing function of the patients.