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Brushing your teeth twice a day is a key part of oral hygiene, but for many, this doesn't always solve the problem of bad breath. Dentists say halitosis, or bad breath, often has underlying causes that brushing alone can't eliminate.
So why can your breath sometimes smell bad even after brushing your teeth, and what can you do about it?
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She recommends flossing once a day. “Flossing gets into places a toothbrush can't, so don't skimp on brushing and flossing!” While Tomsik prefers traditional floss, she says dental floss and water picks also work. The key is to use them consistently.
But even if you brush and floss, odor-causing bacteria can still remain in your mouth.
“Sulfur-producing bacteria thrive on the surface of the tongue and in the back of the throat,” Dr. Fatima Khan, a dentist and co-founder of Riven Oral Care, a company that makes probiotic mouthwashes, told Live Science in an email. These bacteria break down proteins in food very quickly and can release foul-smelling molecules called volatile sulfur compounds (VSCs) from the back of the tongue and throat, she added. (VSCs are the gases that cause the classic “rotten egg” odor.)
Dr. Jenna Chimon, a leading cosmetic dentist at Long Island Veneers, often sees patients who brush their teeth but neglect other important aspects of oral hygiene. “If they don't brush their tongue or teeth properly, bacteria can linger and cause odor, no matter how minty their toothpaste,” Chimon told Live Science in an email.
Her top recommendation for patients seeking help for bad breath is to improve their oral hygiene. “Cleaning your tongue, whether with a tongue scraper or a toothbrush, is crucial, as is flossing daily.”
According to Khan, another possible cause of bad breath is dry mouth, often caused by certain medications (such as antihistamines), mouth breathing, or the use of antiseptic mouthwashes. Saliva acts as a natural cleanser in the mouth, washing away food particles and bacteria. Insufficient saliva prevents the mouth from cleaning properly, leading to a buildup of bacteria and the development of bad breath.
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Another issue that may need to be addressed, according to Chimon, is hydration.
Regular coffee consumption may worsen the problem because caffeine reduces saliva production for two hours after drinking, contributing to dry mouth and bad breath, research shows.
Bad breath can also be caused by food. Strong-smelling foods, such as garlic and onions, are absorbed into the bloodstream, enter the lungs, and are exhaled. Smoking—both tobacco and marijuana—also causes bad breath, even after brushing your teeth, because smoke particles linger in the mouth, throat, and lungs. It also dries out the mouth, creating a favorable environment for the growth of odor-causing bacteria.
Certain medical conditions can also cause bad breath. Gum disease is one of the most common, said Chimon. “Inflammation or infection in the gums creates pockets where bacteria live and multiply, causing bad breath.” (Smokers are at higher risk of developing gum disease than non-smokers.)
In addition to proper oral hygiene to reduce gum inflammation, a simple home remedy for preventing gum disease is rinsing your mouth with warm salt water, said Khan. “Salt water not only cleanses the affected area but also reduces inflammation, creating a favorable environment that inhibits the growth of pathogenic bacteria.”
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Besides oral issues, sinus problems are another often-overlooked cause of bad breath, said Chimon. For example, sinus problems, which cause mucus to drain down the back of the throat, and gastroesophageal reflux, in which stomach acid irritates the nasal passages and sinuses when it enters the stomach, “can lead to bad breath,” explained Han.
Furthermore, diabetes without adequate blood sugar control can trigger ketoacidosis, a condition in which the body burns fat instead of glucose. This results in a characteristic fruity odor on the breath.
Disclaimer
This article is for informational purposes only and does not contain medical advice.
Clarissa Brincat, Live Science contributor
Clarissa Brincat is a freelance writer specializing in health and medical research. After earning a master's degree in chemistry, she realized she enjoyed writing about science more than actually doing it. She learned how to edit scientific articles as a chemistry editor and then transitioned to a medical writing position at a healthcare company. Writing for doctors and experts is challenging, but Clarissa wanted to connect with a wider audience, which naturally led her to freelance writing in the health and science fields. Her work has also appeared in Medscape, HealthCentral, and Medical News Today.
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