EVALUATION OF EFFECTIVENESS OF TRANSCUTANEOUS ELECTRIC NERVE STIMULATION (TENS) THERAPY ON SALIVA PRODUCTION IN POSTRADIATION ORAL CANCER PATIENTS.

Saliva is a critical fluid necessary for oral health. Xerostomia is the subjective complaint of oral dryness with an objective decrease in salivary volume. The major causes of xerostomia are medications, radiation therapy of head and neck cancers and autoimmune disorders like Sjogrens syndrome.

A substantial decrease in salivary function has significant impact on quality of life and results in increased burden of long term dental care. Systemic agents like pilocarpine stimulate salivary flow but have many contraindications and unfavourable side effects.

Augmentation of salivary reflexes through application of an electrical stimulus has been reported to increase salivary flow and alleviate xerostomia in patients after radiotherapy to head and neck, without local or systemic side effects. The purpose of this study is to evaluate the effectiveness of TENS therapy in stimulating salivation in postradiated oral cancer patients.

This study is planned as a pilot study to gain baseline data about the efficacy of TENS in patients with Xerostomia after radiotherapy. In a study involving 50 patients with xerostomia Mittal et al had shown that salivary output can increase by 0.045 ± 0.02 ml/min after application of TENS.  Since our study population was containing patients post radiotherapy we expected the increase to be much lesser. Using the paired difference model a sample size of 25 at an alpha of 0.01 has a power of 80% to detect an increase of 0.015 ml/min after application of TENS with a standard deviation of difference of 0.02 ml/min. In order to account for potential incompliance the sample size is increased to 30.

Results:

29 out of 30 patients demonstrated increased saliva flow during stimulation. A statistically significant improvement in saliva production (P<0.05) during stimulation was noted. Mean unstimulated saliva flow was 0.056ml/min and mean stimulated saliva flow was 0.12ml/min with a median increase of 0.06ml/min. Interval to application of TENS after radiotherapy significantly influenced the improvement in salivary flow.