• all patients will receive supragingival and sub-gingival plaque and calculus debridement (SRP) with an ultrasonic scaler and a manual universal curette where, conventional scaling and root planning (SRP) to the bottom of the pocket of 4 mm or more will be done to preserve any residual fibers attached and to avoid unintentional curettage and prevent any possible shrinkage.
• Subgingival saline irrigation will be performed adjunctively to Sub-gingival curettage.
• All teeth will be polished with a rubber cup. Photodynamic therapy will be done with a blue halogen curing light of wavelength 470 nm with intensity 620 mW/cm2, a continuous mode for 5 min.
• The photosensitizer will be applied to the bottom of the periodontal pocket with the help of an applicator. After 5 min, the photosensitizer will be rinsed with saline and will be exposed to on blue halogen curing light "0" day, which will be repeated on 7th and 21st day.

• all patients will receive supragingival and sub-gingival plaque and calculus debridement (SRP) with an ultrasonic scaler and a manual universal curette where, conventional scaling and root planning (SRP) to the bottom of the pocket of 4 mm or more will be done
• Subgingival saline irrigation will be performed adjunctively to Sub-gingival curettage.
• All teeth will be polished with a rubber cup. Photodynamic therapy will be done with a blue halogen curing light of wavelength 470 nm with intensity 620 mW/cm2, a continuous mode for 5 min.
• The photosensitizer will be applied to the bottom of the periodontal pocket with the help of an applicator. After 5 min, the photosensitizer will be rinsed with saline and will be exposed to on blue halogen curing light "0" day, which will be repeated on 7th and 21st day. Serum vitamin D levels will be assessed by blood sample at baseline and 6 weeks after intervention in test group.

non-surgical periodontal therapy (SRP) and Photodynamic therapy (PDT) with systemic vitamin D

CAL will be measured form cemento- enamel junction (CEJ) to the depth of the pocket using UNC periodontal probe.

• It will be recorded at 6 sites per tooth, the recorded readings will be used to generate mean values at each time point.

PPD will be measured form free gingival margin (FGM) to the depth of the pocket using UNC periodontal probe.

Assessment after 30 seconds after gentle brushing of the sulcus with a periodontal probe, measurement quadrant