Inclusion Criteria:  healthy subjects age 35-75 years diagnosed with chronic periodontitis at least four non-adjacent teeth with proximal sites with a PD ≥6 mm and clinical attachment loss ≥5 mm with BoP and no radiographic signs of apical pathology. either smokers (>10 cigarettes per day for at least 5 years) or non-smokers (never smoked or not within the last 5 years).  Exclusion Criteria:  subjects who presented with any current medical condition or used medications known to affect periodontal healing incorrectly reported smoking status use of antibiotics within 6 months of the study received subgingival scaling within 6 months of the study