All subjects will be patients of record in the Graduate Periodontics clinic at the UT School of Dentistry. These individuals will have already been diagnosed with chronic periodontitis and require surgical intervention to treat the disease process. All patients will have received initial periodontal therapy consisting of oral hygiene instructions and scaling and root planing. Once enrolled in the study, all subjects will receive surgical therapy involving opened flap debridement of the affected furcation defects along with membrane isolation of the defect. The test group will have debridement performed with the Er,Cr:YSGG laser and ultrasonic cleansing, while the control group will have hand instrumentation along with ultrasonic cleansing. This procedure will take approximately 1.5 hours. Postoperative appointments at 1,2,4,8 weeks requiring 15-30 minutes per appointment; at 3 months for periodontal maintenance and reinforcement of home care requiring 45 minutes; and at 6 months for periodontal maintenance, reassessment of the furcation defect and correction of residual defects requiring 75 minutes. Patients will be exited from the study 2 weeks after the last maintenance appointment and placed on recall with the Department of Periodontics dental hygienist. The total time commitment for each patient is 6 months.