Scaling and root planing(SRP)followed by topical application of active oxygen-releasing gel (0.4 mL) for 3 minute

Scaling and root planing (SRP) will be performed in a single session, followed by the topical application of active oxygen-releasing gel (0.4 mL) for 3 minutes. Subsequently, antimicrobial Photodynamic Therapy (aPDT) will be applied using a diode laser (635 nm) with tolonium chloride as a photosensitizer. The laser irradiation will be performed at an energy density of 6 J/cm2 for 30 seconds per site."

Scaling and root planing using ultrasonics and Gracey curettes.

14 stage III periodontitis patients will undergo scaling and root planing in a single session followed by topical application of active oxygen-releasing gel (0.4 mL) for 3 minutes then irrigating the targeted pocket using tolonium chloride will be stopped once the tolonium chloride solution will be observed at the free gingival margin of the pocket. After 60 seconds, irradiation inside the periodontal pocket with diode laser (635nm) for 200 mW, 30 seconds, energy density of 6 J/cm2, tip diameter of 400 µm, using continuous modes of irradiation, the laser fiber tip will be positioned parallel to the long axis of the tooth, move in a steady vertical inward and outward motion to ensure that the entire pocket will be adequately covered.

non-invasive, visual clinical tool (0-4 scale)focuses on color, texture, and contour changes across facial, lingual, mesial, and distal surfaces of tooth ,modified gingival Scoring Criteria for MGI (0-4) higher scores indicate more severe gingival inflammation higher a worse clinical outcome.

0: Absence of inflammation (normal gingiva).

1. Mild inflammation - slight change in color/texture in part of the marginal or papillary gingiva.
2. Mild inflammation - slight change in color/texture in the entire marginal or papillary gingiva.
3. Moderate inflammation - bright surface, erythema, edema, and/or hypertrophy of the marginal or papillary gingiva.
4. Severe inflammation - severe erythema, edema, and/or marg

a clinical parameter measured by inserting a periodontal probe to the base of a gingival pocket.The probe is inserted parallel to the root surface and "walked" around the gingival sulcus, with bleeding assessed 30-60 seconds after probing.recorded as a percentage of positive bleeding sites out of the total sites probed (6 sites per tooth). A higher percentage of bleeding sites indicates increased gingival inflammation and a worse outcome.

measured in millimeters using Williams calibrated probe from the cemento-enamel junction to the bottom of the pocket .This measure reflects the extent of periodontal tissue destruction. Higher values in millimeters indicate greater attachment loss and a worse clinical condition.

Clinical measurement of the distance in millimeter from the gingival margin to the base of the periodontal pocket using Williams calibrated probe.Deeper pockets indicate more severe periodontal disease. Higher values represent a worse outcome.

Sub-gingival dental plaque biofilm (before the intervention and one month after the intervention) will be collected using size 30 paper point after ensuring good isolation of the operating field. quantitative real time PCR will be performed using universal bacterial 16SrRNA gene primers and species-specific primers targeting the 16S rRNA genes of Treponema denticola (Td), and Porphyromonas gingivalis (Pg), to estimate the relative abundance of Td and Pg among total oral microbiota before and after treatment