Acute Salivary Flow Rate Response to Transcutaneous Electrical Nerve Stimulation Versus Electro-acupuncture

Inclusion Criteria: \- 1) 100 healthy adult volunteers from both sexes. 2) Application time of TENS and electro-acupuncture will be fixed for all volunteers between 9:00 am to 11:00 am. 3\) The volunteers will be advised to have nothing to eat, drink, chew gum, coffee intake and oral hygiene before the test at least by one hour Exclusion Criteria: * 1\) Volunteers under 18 years of age. 2) Pregnant females. 3) Habits (mouth breathing, smoking, alcohol and drug abuse). 4) Cancer patients (patients on chemotherapy/immunotherapy and history of head and neck radiotherapy). 5\) Cardiac patients (cardiac pacemakers and defibrillators). 6) Patients wearing hearing aids. 7) Chronic inflammatory autoimmune disease such as Sjogren's syndrome (an autoimmune disease that induces exocrine dysfunction and abnormalities), other rheumatologic diseases (including: rheumatoid arthritis, Systemic lupus erythematosus, scleroderma, mixed connective tissue disease, etc), sarcoidosis, amyloidosis, Crohn's disease and ulcerative colitis. 8\) Acute oral inflammatory disorders, gingivostomatitis, tonsillitis and dehydration. 9\) Infectious diseases e.g (HIV/AIDS, HCV and Tuberculosis). 10) Patients undergoing the use of any drugs. 11) Patients with neurological disorders: stroke, parkinson's disease, epilepsy, Bell's palsy, Alzheimer's disease, Patients with cerebrovascular problems, patients with a history of aneurysm and patients with transient ischaemia. 12\) Salivary gland diseases and disorders: agenesis of the salivary glands, sialoadenitis and sialolithiasis. Patients with Salivary duct ligation, history of salivary gland pathology, salivary gland inflammation and parotid gland infection. 13\) Psychogenic diseases and conditions: stress, anxiety, nervousness, depression, schizophrenia and eating disorders ( bulimia). 14\) Endocrine diseases: hyperthyroidism, hypothyroidism, Cushing's syndrome and Addison's disease and systemic diseases like diabetes mellitus. 15\) Others: cystic fibrosis, hypertension, fibromyalgia, chronic fatigue syndrome, burning mouth syndrome, primary biliary cirrhosis, liver transplant candidates, renal diseases, renal dialysis, anemia and atrophic gastritis.