Summary: In a very small interim analysis of a randomised trial in type 2 diabetes with dry mouth, low-level laser therapy and TENS to the salivary glands improved stimulated salivary flow and shifted the oral microbiome, with laser increasing bacterial diversity more than TENS.
PICO Summary
| Element | Detail |
|---|---|
| Population | 8 individuals with type 2 diabetes and reduced salivary flow; exploratory interim analysis of an RCT, Brazil. |
| Intervention | Low-level laser therapy (G1), TENS (G2), or both (G3) to the salivary glands, twice weekly for 10 sessions. |
| Comparison | Within-subject, baseline versus post-treatment (no separate control group). |
| Outcome | Seven participants improved stimulated salivary flow to or within normal range (>0.7 mL/min). Bacterial diversity was higher after laser than TENS. Firmicutes and Fusobacteriota increased while Actinobacteriota and Proteobacteria decreased, and low-abundance taxa fell, suggesting a possible clearance effect. No adverse effects. |
Expert Commentary
This is an early, exploratory study best read as hypothesis-generating rather than practice-changing, and its own authors frame it that way. The clinical problem is real and underappreciated: diabetic salivary dysfunction is usually functional rather than destructive, so there is a plausible target for stimulation, and the rationale, laser enhancing cellular metabolism and TENS driving neuromuscular activity, is coherent. The signals are encouraging, with most participants restoring stimulated flow and laser appearing to enrich microbial diversity, which generally indicates a healthier oral ecosystem. But the constraints here are unusually severe and must dominate interpretation: this is an interim analysis of just eight people with a within-subject design and no true control group, so regression to the mean and expectation effects cannot be excluded, durability after treatment is unknown, and whether the microbiome shifts translate into fewer caries, less periodontitis, or better glycaemic control is entirely untested. Can I use this with my patients? Only at the experimental margins. For a diabetic patient with troublesome dry mouth refractory to standard measures, I might mention these physical therapies as emerging options while continuing conventional xerostomia management, and I would not present them as established on the strength of eight cases.
References
de Melo JLMA, Nunes FPES, Coelho CPES, et al. Low-level laser and transcutaneous electrical nerve stimulation on salivary glands impact type 2 diabetes mellitus oral microbiome: an interim analysis of a randomized trial. Lasers Med Sci. 2025;40(1):372. doi:10.1007/s10103-025-04609-2