Effects of Tongue Scraping on Plaque, Gingivitis, and Cavities

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Intro: This is the first of a five-video series on tongue cleaning. What is tongue scraping, and is it the most effective way to clean your tongue? Watch the series to find out.

In my last video series on halitosis, I explored the benefits of eating a high-fiber diet for causing a reduction of halitosis. This effect is thought to be due to the “self-cleaning” of the mouth while chewing food.

However, soft foods (like how most fast food is designed so you can gulp it down) do not sufficiently scrape at the coating on your tongue, and so you can be left with a tongue coating, a whitish-gray layer of debris and microorganisms, particularly towards the back of your tongue. During the putrefaction of debris on the tongue, volatile sulfur compounds are created, like the rotten egg gas hydrogen sulfide. This putrefaction process may be responsible for up to 90 percent of bad breath. I did a video called The Best Diet for Halitosis (Bad Breath) on dietary tweaks to lessen the formation of these compounds in the first place. But if you are unwilling or unable to change your diet, natural self-cleaning mechanisms might not necessarily remove the tongue coating if it’s really thick, in which case, mechanical tongue cleaning can remove debris. But often tongue cleaning is not considered a routine part of oral hygiene. Should it be? Let’s find out.

Unless you have some pocket of pus from something like periodontal disease, the most likely source of bad breath is the surface of your tongue. And it’s not like there is one bad actor bacteria. Dozens of different bacteria can produce the volatile sulfur compounds from the sulfur-containing amino acids concentrated in animal protein. That’s why probiotics may fail to change the emissions. In fact, if you compare the tongue microbiome in healthy subjects versus those with bad breath, they have almost the same bacterial composition. So, it may be less which type of bacteria you have on your tongue, and more the sheer quantity of how many bacteria you have living there. Population studies suggest that the use of tongue scrapers is associated with less severe symptoms of halitosis, but maybe those who use tongue scrapers are also more scrupulous about oral hygiene in other ways. The only way to know for sure is to put it to the test.

First, though, some background. Tongue scraping and brushing have been practiced for centuries in many continents around the world, but has been almost unknown elsewhere. “Why clean your tongue?” asked this editorial in The Journal of the American Dental Association. Dentists, hygienists, and manufacturers of toothpaste, toothbrushes, and floss have long emphasized the need to remove dental plaque from your teeth to prevent cavities. But “[w]hy do [so] many Americans produce two immaculate, shining rows of teeth separated by an organ covered with millions of microorganisms, emitting a strong malodor?”

First of all, though, what might be the effect of tongue brushing on formation of dental plaque?  If you stopped brushing your teeth completely, would it matter if you brushed your tongue? No. Stop brushing your teeth, and the plaque builds up either way. Yeah, but what if you continue brushing but just add tongue brushing along with tooth brushing? That has no effect on the buildup of plaque on your teeth, suggesting that the majority of the important plaque-forming bacteria might not originate from the tongue, though another reason for not finding an effect of tongue brushing on plaque formation may be that brushing of the back of the tongue is difficult because it can make you gag.

What about gingivitis—gum inflammation? Those who clean their tongues tended to have less bleeding on probing, suggesting healthier gums, but you don’t really know if it’s cause and effect until you put it to the test. A randomized controlled clinical trial comparing tongue scraping versus no tongue scraping, and…it made no significant difference.

What about tongue scraping as a means of reducing the acid-producing bacteria that cause cavities called Streptococcus mutans? This study showed a beneficial effect, compared to using Listerine brand oral care strips or salt water rinses, but another study found no significant effect. Maybe the population of bacteria is just so large that scraping removed only a small portion, or maybe it’s like sweeping a rug, where you’re just kind of moving stuff around. The bottom line is that studies investigating the role of tongue brushing and plaque accumulation or gum inflammation show conflicting results. So, on the basis of the medical research, there appears to be no data that justify the necessity to clean the tongue on a regular basis. Ah, but the one exception would be oral malodour. It works for combatting bad breath, which we’ll explore next.

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Motion graphics by Avo Media

• animal protein
• bad breath
• cavities
• dental health
• fiber
• halitosis
• inflammation
• probiotics
• tongue scraping