This a patient and outcome assessor blinded, multiple arm, randomized placebo controlled clinical trial. The goal of the study is to study the adjunctive effect of 940nm laser photobiomodulation therapy (PBMT) in precancerous condition like moderate Oral submucous Fibrosis in increasing the mouth opening. It will also assess the the effect of PBMT on oral burning sensation cheek flexibility, electromyography of bilateral masseter muscle, inflammatory and fibrogenic cytokines and oral health quality of life at baseline and after 1 and 3 months of PBMT. Adult subjects fulfilling the selection criteria will be prospectively recruited after ethical clearance and informed written consent. They will be randomized into 3 groups in 1:1 :1 distribution The three groups are as follows: Group A: Photobiomodulation therapy given intraorally on bilateral buccal mucosa and extraorally (sham) with conventional non-invasive management. Group B: Photobiomodulation therapy given intraorally (bilateral buccal mucosa) and extraorally (bilateral masseter muscle) with conventional non-invasive management. Group C: Sham (Use of laser handpiece with only red guide light and without using the foot pedal which activates the laser)Photobiomodulation therapy(Placebo) (Intraoral and Extraoral) with conventional non-invasive management. The conventional non invasive management in Oral submucous fibrosis which all the groups will receive are as follows: Brief behavioral Tobacco, areca nut and alcohol habit cessation counseling as per WHO 5As and 5Rs technique at baseline and each follow up. Oral prophylaxis Removal of oral irritational factors like sharp teeth, appliances or prosthesis, impacted buccoverted third molars, parafunctional habits Oral hygiene maintenance instructions Oral physiotherapy(Mouth opening and cheek ballooning exercises) Control of systemic conditions (Anemia, Diabetes, hypertension, thyroid disorders) by specialist referral Removal of all predisposing factors for oral candida infection Advocacy for safe sexual practices Nutrition and diet counseling( seasonal and regional food rich in nutrients, vitamins, antioxidants avoidance of spicy /sour/ hot foods and drinks) Regular surveillance for malignant transformation All the outcome parameters will be assessed at baseline and 1 and 3 months after PBMT.