Tongue Cleaning – Is it Sufficient?

Methods: 19 subjects participated in this blinded crossover study. Subjects abstained from oral hygiene, eating and drinking from 10pm the previous evening. Tongue samples were collected at baseline and within 15 minutes of one of three procedures: teeth brushing alone; teeth brushing plus tongue scraping (30s); teeth brushing plus tongue cleaning using a high speed vacuum ejector and irrigation with 20ml antibacterial mouthwash. Subjects then brushed twice daily for 3 days apart from the second group who additionally scraped their tongue twice daily. On day 4, baseline and post-treatment samples were collected as per day 1. Bacteria (total anaerobes, gram-negative anaerobes, VSC-producing bacteria and Streptococcus salivarius) were enumerated using appropriate selective media.

Results: The tongue dorsum was colonized by all 4 bacterial categories (log₁₀ 6-8 cfu/sample). For subjects who brushed their teeth only, there was a significant reduction from baseline for S. salivarius only. In contrast, tooth brushing plus tongue scraping resulted in statistically significant reductions from baseline for all bacterial categories (range log₁₀ 0.11 to 0.40 cfu/sample). Highly statistically significant reductions (log₁₀ 1.11 to 1.96 cfu/sample) were observed for subjects who underwent thorough tongue cleaning with the saliva ejector/mouthwash. To determine longevity of treatment effects, baseline bacterial loads for days 1 and 4 were compared. Only daily tongue scraping resulted in statistical significant reduction in baseline microbial loads on day 4.

Conclusion: While mechanical tongue cleaning with or without chemical intervention can reduce bacterial load on the tongue, this effect is transient, and regular tongue cleaning is required to provide a long lasting (overnight) reduction in bacterial numbers. Nevertheless, tongue cleaning is an oral hygiene procedure that is little practiced due to discomfort and/or lack of awareness.