The aim of this study is determining the additional effect of a 2-week home usage of chlorhexidine in periodontitis patients undergoing scaling and root planing supplemented with a dual-strain probiotic lozenge.

Inclusion Criteria:

• Diagnosed with generalized (>30% of teeth affected) periodontitisstage III and IV periodontitis, grade B or C (C only with smoker modifier) = generalized chronic periodontitis including smokers
• A minimum of three natural teeth in each quadrant, excluding third molars
• Willing and able to give informed consent
• Not more than 50% of the patients in each group will be smokers.
• Smokers should smoke between 10 to 40 cigarettes a day

Exclusion Criteria:

• Patients with localized periodontitis or periodontitis stage I or II or grade A or grade C or grade C with diabetes modifier
• Patients with orthodontic appliances (removable or fixed)
• Pregnant or lactating woman
• Patients with a history of systemic diseases that may correlate with periodontal health, such as diabetesrheumatic fever, liver or kidney disease, and neurological deficiencies
• Patients taking medication which may affect the periodontium (bisphosphonates, phenytoin, cyclosporin, nifidepine, chronic use of non-steroidal anti-inflammatory drugs)
• Patient who had taken systemic antibiotics up to 3 months prior to treatment or medical conditions requiring prophylactic antibiotic coverage
• Participation in any other clinical study
• Tobacco chewing or sniffing