The goal of this clinical trial is to Investigate the clinical and microbiological efficacies of Laser disinfection and ICG-mediated aPDT as adjunct to RSD for patients with periodontitis. The main question it aims to answer is:

Does the use of laser disinfection or ICG-mediated aPDT as adjunct to RSD are effective in improving clinical parameters and reducing the load of periodontal pathogens.

Participants will undergo full-mouth supragingival debridement by using ultrasonic device at baseline.

All patients will be instructed to brush their teeth twice daily and will be supplied with the same type of tooth paste and toothbrush, with suitable interdental aids.

All the patients will be instructed to attend again after 7 days. One week later, sites randomly allocated to control (Ctrl) group and test groups which will receive, in addition to RSD, either aPDT or periodontal pocket disinfection (Biolase). For all groups, sites with initial PPD 4-6 mm will be treated with RSD using area specific (Graecy) curettes.

Inclusion Criteria:

• Adult subjects (>18 years), non-smoker, with no history of any systemic disease such as diabetes mellitus. Additionally, subjects are not currently under active periodontal therapy or joining other trial in the last 3 months. All patients must be diagnosed with generalized periodontitis with at least 3 teeth in three different sextants (Anterior teeth and premolars) with 4-6 mm PPD and positive BOP. Periodontitis cases will be defined by presence of interdental CAL affecting ≥2 non adjacent teeth or if CAL at buccal/lingual aspects associated with PPD >4mm at ≥2 teeth.

Exclusion Criteria:

• Patients will be excluded if they were not diagnosed with periodontitis, smokers, those consuming antibiotics, regular user of nonsteroidal anti-inflammatory drugs, or receiving periodontal treatment 3-months prior to the study. Additionally, pregnant or mothers in a breastfeeding period, and those not willing to participate will be also excluded.

Sites will randomly be assigned to test or control groups according to a computer-generated list. Allocation concealment will be assured by opaque, sealed envelopes prepared and sequentially numbered by a person not otherwise involved in the study. The person responsible for delivering treatment will be aware about allocation of the groups, while the assessor will be blinded.