The primary purpose is to evaluate the effectiveness of photobiomodulation laser application in the management of patients with radiotherapy-induced hyposalivation. Secondary, to assess the changes in the scores of the patient's oral health-related quality of life using validated measurements.

Head and neck cancer is a general term used to describe epithelial malignancies in the oral cavity, paranasal sinuses, nasal cavity, pharynx, and larynx. These malignancies are often presented as squamous cell carcinoma (SCC) of the head and neck with tobacco and alcohol consumption remaining the two main risk factors. In addition, human papillomavirus has been identified as another risk factor in a limited subset of these malignancies. More specifically, oral cancer accounts for 2%-4% of all cancer worldwide with 90% of these cases presented as SSC worldwide compared to 44.8% in Saudi Arabia. Clinically, patients often presented with white and/or red patches, hoarseness, non-healed ulcers, throat pain, and painless cervical lump which may persist for more than 3 weeks period.

Most head & neck cancer patients who received radiotherapy are likely to experience xerostomia and salivary glands hypofunction, mucositis, and possibly the loss of taste.

Furthermore, the effect of hyposalivation is not only limited to taste dysfunction but also associated with opportunistic infections, difficulty in chewing and speaking, rapid progression of caries, and oral mucositis. All these secondary complications are usually associated with pain and discomfort which will heavily affect the patient quality of life if they are untreated. Treatment options include moisturizing agents or artificial saliva which have a palliative effect however they are not preferred nor accepted by most patients.

The outcome of low-level laser therapy usage on cancer patients is well documented and well established in the literature. The vast majority of the results suggest that this therapy is an effective treatment option to stimulate salivary glands flow and decrease xerostomia/hyposalivation symptoms. In the present study, the efficiency of this treatment option will be tested as well as the changes in the patient's quality of life during and after the radiation treatment.

Inclusion Criteria:

• Patients aged 18 and above
• Clinically diagnosed with hyposalivation [an unstimulated salivary flow rate of ≤ 0.1ml per minute] (31) due to recent radiation therapy of SCC of the head and neck.

Exclusion Criteria:

• Individuals with systemic diseases that could affect the salivary glands function such as (e.g. Sjogren syndrome) and medications (e.g. beta-blockers and diuretics for hypertension).
• Individuals who had an allergy to toluidine blue stain.