Evaluation of the Effects of Transcutaneous Electrical Nerve Stimulation (TENS) On the Whole Salivary Flow Rate in Healthy Adult Subjects –A Clinical Study

Background and Objective: Saliva is a critical fluid necessary for oral health. Xerostomia and salivary gland hypofunctioning are associated with advancing age, autoimmune diseases, head and neck radiation, smoking and recreational drug usage. Palliative management of xerostomia includes wetting agents such as ice chips, saliva substitutes, increased water intake, applying lip balm, chewing sugar free gum or sucking sour sugar-free lemon drops, paraffin, and citric acid containing lozenges and rinses. Systemic agents stimulate the salivary flow but have unfavourable side effects. Therefore, this study was undertaken to evaluate the effects of transcutaneous electrical nerve stimulation (TENS) on the whole salivary flow rate in healthy adult subjects. Study Design: Seventy three healthy adult subjects with no history of salivary gland disorder were enrolled in the protocol. TENS electrode pads were placed externally on the skin overlying the major salivary glands. Unstimulated whole saliva was collected for 5 minutes into a graduated test tube. The TENS unit was then activated and stimulated saliva was collected for another 5 minutes in a separate graduated test tube. Results: Sixty nine out of seventy three demonstrated increased whole salivary flow when stimulated via TENS unit. Four subjects showed a decrease in the salivary flow. The mean unstimulated salivary flow rate was 0.479±0.152 ml/min while under stimulated condition it was 0.724±0.189 ml/min, thereby showing a percentage increment of 51.1% following TENS application. Statistical analysis of flow rates showed the difference to be significant (p<0.001) Conclusion: The TENS unit was highly effective in stimulating the whole salivary flow rate in healthy adult subjects. A further study in patients with xerostomia secondary to various local and systemic causes is required.