Effects of photobiomodulation and bethanechol chloride treatment on salivary composition and flow rate in head and neck cancer patients undergoing radiotherapy: longitudinal interventional experimental clinical study.

Objective: To evaluate the efficacy of photobiomodulation therapy (PBMT) and bethanechol chloride (BC) on the quantity and quality of saliva in patients undergoing radiotherapy (RT) for head and neck cancer.

Methods: Saliva samples were collected from patients before and after RT, who were treated with PBMT or BC. Clinical parameters, including salivary flow rate (SFR), pH, xerostomia, and concentrations of macro and microelements in saliva, were assessed.