It is established that brushing teeth regularly helps to prevent cavities and save teeth. The most efficient times to brush your teeth may be before or after breakfast and before you go to bed at night.
Brushing Before Breakfast
When you wake up in the morning, your mouth is loaded with bacteria that accumulated in your mouth while you slept. Many breakfasts contain sugar and refined carbohydrates, which bacteria convert into acids that can dissolve the enamel in your teeth. Brushing before breakfast helps to reduce the number of bacteria in your mouth and increases saliva in your mouth to help wash away some bacteria and reduce mouth acidity (Biomed Res Int, Feb 26, 2018:3904139). Most toothpastes contain fluoride that helps to strengthen tooth enamel. Brushing before breakfast removes a lot of the bacteria before they can convert the food you eat to acids. Your mouth is more acidic after you eat, and brushing then is likely to remove more enamel (Dent J (Basel), 2016 Sep; 4(3): 25).
Brushing After Breakfast
After you eat, the bacteria in your mouth have started to convert the food you ate to enamel-dissolving acids. The longer you leave food in your mouth, the more enamel-dissolving acids are formed. Brushing after eating removes more food from your mouth, so that less acid is formed. It also prolongs the time fluoride from toothpaste stays in your mouth to reduce the number of acid-forming bacteria and to make your enamel more resistant to acid-causing cavities. However, brushing mechanically removes enamel, and the more acid is in your mouth when you brush, the more enamel is removed. This means that it would be best to wait at least 30 minutes after eating for a reduction of the meal-induced mouth acidity. The American Dental Association recommends waiting if possible, at least an hour after eating, to brush your teeth. Brushing after breakfast reduced strep mutans bacterial counts by 38 percent, which was more than the 29 percent reduction of that bacteria from brushing before breakfast (J Microsc Ultrastruct, Oct-Dec, 2022;10(4):168-173).
Your saliva is most acidic immediately after you eat and the acidity of saliva is progressively reduced after that. However, saliva remains acidic usually for up to an hour after you finish eating (International J of Health Sciences, March 11, 2022;6(S110:703-709)).
Foods that are most likely to make your mouth more acidic include:
• sugared and carbonated drinks
• anything with sugar, corn syrup, honey or maple syrup
• citrus fruits and juices (oranges, grapefruit, lemons, limes)
• dried fruits
• refined carbohydrates in breads, pastries and most dry breakfast cereals
If you can’t wait for an hour after eating, brush when it is convenient; it is more healthful to brush any time than not to brush at all.
Brush Before You Go to Bed
Several studies show that brushing before you go to sleep reduces cavities (Children (Basel), 2021 May; 8(5): 416). One study showed that people who brushed their teeth regularly at night were less likely to die from heart attacks (Sci Rep, June 2023;13:10467), but the study did not offer opinions on a possible connection.
Floss Before You Brush
Brushing removes bacteria more effectively if you remove the larger food particles first by flossing before you brush (J Periodontol, July 2018;89(7):824-832). Toothpicks are ineffective at removing food particles and plaque, but flossing helps to remove plaque and food between your teeth that your toothbrush cannot reach. Flossing after you brush can leave extra food particles between your teeth.
More Brushing Tips
• Don’t rinse your mouth right after brushing. Wait a while before you use mouthwash or breath fresheners that will remove the fluoride left in your mouth from your toothpaste.
• Replace your toothbrush every 3-4 months. Frayed toothbrushes are less efficient at removing food particles and plaque from your teeth.
• Water flossers (waterpiks) use a stream of pulsating water to clean away food particles, bacteria, and plaque between teeth and under the gumline. You may want to use a waterpik if you wear braces, have nonremovable bridgework, have crowns, have dental implants, or have difficulty brushing your teeth because of arthritis or any other reason.
• Symptoms of gum disease can include bad breath, tender or bleeding gums, or loose teeth. Check with your dentist.
My Recommendations
To help prevent cavities and gum disease, floss and then brush your teeth at least twice a day. Brush before breakfast to reduce cavity-causing bacteria and at night to get rid of tooth plaques that can accumulate throughout the day (Incisive Dent J Maj Incisive Dentistry, 2017;6(2):1-8; International Journal of Health Sciences, 2022;6(S10):703-709). To help keep fluoride from toothpaste in your mouth, don’t rinse your mouth or use mouthwash immediately after you brush.
