Inclusion Criteria:  • Subject diagnosed with generalised periodontitis Stage III of any grade (Caton et al., 2018).  Age ≥21 years old. Subject is in good general health without any remarkable past history of disease except for well controlled diabetes (HbA1c ≤6.5%) (Clinical practice guidelines on management of type 2 diabetes mellitus., 2020). Presence of at least 20 teeth. Presence of at least 2 non-adjacent sites located in contralateral quadrant with interproximal probing pocket depth (PPD) ≥6mm.  Exclusion Criteria:  • Received subgingival scaling in the previous 6 months.  Use of antibiotic in the past 6 months. Taking steroidal and non-steroidal anti-inflammatory agents on a daily basis. Medical condition requiring antibiotic prophylaxis. Pregnancy or lactating. Smoking ≥10 cigarettes per day.