Electrical nerve stimulation for xerostomia: A meta-analysis of randomised controlled trials

Xerostomia leads to caries, infection and overall psychological discomfort. Salivary substitutes and pharmacological agents have been tried only with temporary relief. The use of transcutaneous electrical nerve stimulation (TENS) has been contemplated on by various researchers for treatment of xerostomia. We carried out the present review as a systematic compilation and quantitative synthesis of the existing evidence related to the utility of TENS in patients with xerostomia.

Six randomized controlled trials were identified from databases for inclusion and analysed using non-Cochrane mode in RevMan 5.0 software. The heterogeneity between the studies were assessed using Forest plot, I² statistics wherein more than 50% was considered to have moderate to severe heterogeneity and Chi-square test with a statistical P-value of less than 0.10 to indicate statistical significance.

Results show that the effect of TENS on salivary flow rate in 369 participants with SMD [95% CI] was 0.63 [-0.03, 1.29] and was not statistically significant.

To conclude, the current evidence does not support the use of TENS in patients with xerostomia and may be considered as a salivary substitute for symptomatic improvement. However the type, frequency and amplitude of current used needs to be studied in detail. High quality randomized controlled trials with adequate power are required, either to support or refute the use of TENS in xerostomia.