INTRODUCTION: Periodontitis is a chronic inflammatory disease resulting from an interplay between microbial plaque and the host immune-inflammatory response. The identification of specific biomarkers in the gingival crevicular fluid (GCF) can be correlated with the biologic processes including inflammation, connective tissue degradation and bone turnover and hence offer the potential to be used as diagnostic or prognostic markers of periodontal disease and treatment outcome. The primary goal of-nonsurgical periodontal therapy is to establish a periodontium that is in remission of periodontal disease. Although the gold standard of periodontal therapy till date is scaling and root planing (SRP), the use of more efficient and less traumatic adjunctive therapeutic modalities like lasers, may provide long lasting therapeutic benefits. Low level Laser therapy (LLLT), a new era in laser technology uses laser light at low levels with the intention to reduce inflammation and enhance wound healing. Enzymes such as tissue plasminogen activator (tPA) are responsible for regulating the local inflammatory reactions as well as the synthesis of specific extracellular matrix molecules by fibroblasts, angiogenesis and re-epithelization that occur during tissue repair and remodelling. The periodontal inflamed surface area (PISA)  is a very convenient index that reflects the surface area of bleeding pocket epithelium in square millimetres and is calculated using conventional clinical parameters of periodontal health, namely number of sites with Bleeding on probing (BOP) combined with Probing Pocket Depth (PPD),Clinical Attachment Level (CAL) and Location of Gingival Margin(LGM). These values are entered in a freely downloadable spreadsheet available on parsprototo.info website to calculate the PISA value. 

AIM: To investigate the effects of LLLT as an adjunct to non- surgical periodontal treatment by evaluating tPA levels in the gingival crevicular fluid levels and periodontal inflammatory burden in patients with periodontitis.

OBJECTIVE: To evaluate and compare the effects of SRP with and without adjunctive LLLT in the management of periodontitis on GCF levels of tPA and the periodontal inflamed surface area (PISA).

METHODOLOGY: The study will follow a parallel arm, randomised, placebo controlled design. After obtaining a written informed consent, a total of 30 volunteering patients fulfilling the inclusion criteria will be categorized into two treatment groups with 15 patients in each by simple random method using computer generated table. The two groups will be:

• Group 1 - SRP(after evaluation and 7 days after the first session)+sham LLLT(immediately after the completion second session of SRP and 1 week later)

• Group 2- SRP(after evaluation and 7 days after the first session)+LLLT (immediately after the completion second session of SRP and 1 week later).

All patients will be subjected to full-mouth periodontal examination. Clinical parameters will be recorded, PISA will be calculated and GCF samples will be collected at baseline and 3 months after treatment from atleast 3 non adjacent sites with highest PPD eluted in phosphate buffer saline and stored in -20 °C until the assay. LLLT will be applied 0.5mm -1mm away from gingival margin using 660nm diode laser for 20s over each surface covering the oral cavity for group 2 and Sham LLLT application is done using 660nm diode laser without turning on the lights for group 1. The tPA levels in GCF will be quantified using commercially available ELISA kit specific for tPA.