In the daily morning routine, there's a seemingly simple yet long-standing controversial question: should you clean your mouth before or after breakfast? This may seem like a trivial choice, but modern dental science and microbiology show that this decision is crucial to your long-term oral and overall health.
In this guide, we'll answer:
The answer to this controversy? Why choose this option? What is the source of this controversy? And how to perform better oral hygiene?
We hope this information will help you protect your oral and overall health.
Based on current mainstream dental recommendations (including the American Dental Association (ADA)¹), we recommend cleaning your mouth first thing in the morning, then eating breakfast.
Because cleaning your mouth before breakfast can:
1. Cut off the "bacterial buffet"²
If you eat breakfast first, you're essentially providing sugar and carbohydrates for the biofilm. The bacteria then produce acidic substances, immediately starting to erode your tooth enamel.
2. Avoid "swallowing" bacteria³
During sleep, saliva production decreases, reducing the mouth's self-cleaning ability, and biofilm accumulates significantly. Eating with an uncleaned mouth means swallowing a large amount of detached biofilm along with the food, increasing the risk of intestinal diseases.
3. Avoid the acid erosion period⁴
Many breakfast foods (fruits, coffee, juice, bread, etc.) make the oral environment acidic, and during this time, the tooth enamel is temporarily softened. Brushing your teeth immediately afterward is equivalent to "brushing" the acid into the tooth surface, increasing the risk of enamel wear and erosion.
Biofilms are thin, viscous, protective structures formed by the aggregation of numerous microorganisms (mainly bacteria). They bind together by secreting matrix components such as polysaccharides and proteins, adhering firmly to various surfaces. In the oral cavity, biofilms can exist in almost all areas, including tooth surfaces, gum margins, the tongue, the mucous membranes of the upper and lower jaws, and the inner walls of the mouth. Dental plaque, as we commonly call it, is essentially a typical oral biofilm. Unlike individual free bacteria, bacteria within a biofilm form a structure similar to a "miniature community": they cooperate, share nutrients, and are protected by an outer matrix. This structure makes bacteria more difficult to wash away with saliva and less likely to be completely removed by ordinary brushing or rinsing, allowing them to persist stably in the oral cavity for a long time.
If words still don't fully convey the concept of biofilms, try this simple visual aid: Gently touch your palate with your tongue or lightly glide your clean fingers across its surface. The slightly slippery, thin film you feel is often the biofilm structure formed by saliva and microorganisms. This invisible yet real "thin layer" is precisely the carrier for the long-term attachment and changes of the oral microecology.
When the biofilm continues to accumulate and becomes unbalanced, bacteria will continuously metabolize and produce acidic substances and inflammatory factors, which may gradually lead to common oral conditions such as tooth decay, gingivitis, periodontal problems, and bad breath.
Oral biofilms that remain uncontrolled over extended periods may also impact systemic health through inflammatory responses:
① Heart Disease
Pathogenic bacteria present in oral biofilms, such as *Porphyromonas gingivalis*, can easily enter the bloodstream when gums are chronically inflamed. Once inside the bloodstream, they can attach to the vascular endothelium or arterial plaques, triggering a local inflammatory response. This chronic inflammation may not only accelerate the formation of atherosclerosis but also increase the risk of vascular blockage, thereby increasing the incidence of cardiovascular events such as myocardial infarction or stroke. Multiple epidemiological studies have shown that patients with periodontitis have a significantly higher risk of heart disease than those with healthy oral cavity, suggesting that oral biofilms, through inflammation and bacterial transmission mechanisms, may be an important risk factor for heart disease. Therefore, controlling oral biofilms and maintaining healthy gums are also considered as adjunctive measures for preventing cardiovascular disease.
② Alzheimer's Disease
Research shows that some oral pathogens can enter the brain via the bloodstream or neural pathways. For example, toxins released by *Porphyromonas gingivalis* can induce localized inflammatory responses in the brain, leading to neuronal damage and β-amyloid protein deposition—typical pathological markers of Alzheimer's disease. Long-term chronic oral inflammation continuously activates the systemic immune system, leaving the nervous system in a state of low-grade inflammation, further accelerating cognitive decline. In recent years, scientists have discovered a significant correlation between oral health and the risk of Alzheimer's disease, suggesting that controlling oral biofilms and maintaining oral hygiene can help reduce the risk of neurodegenerative diseases.
③ Diabetes
Chronic inflammation in oral biofilms can interfere with insulin signaling pathways, leading to decreased glycemic regulation. Blood sugar levels in patients with periodontitis are often more difficult to control than in those with healthy oral tissues. This two-way relationship means that poor oral health in diabetic patients further exacerbates blood sugar fluctuations, while high blood sugar promotes oral infections and biofilm stability, creating a vicious cycle. Therefore, controlling oral biofilms not only contributes to dental health but is also an important adjunct to diabetes management.
④ Accelerated Aging
Chronic oral inflammation induced by biofilms releases large amounts of inflammatory mediators, such as IL-6 and TNF-α. These substances can enter the bloodstream and continuously stimulate tissues throughout the body. Chronic low-grade inflammation is considered a significant driver of aging, affecting not only skin elasticity and metabolism but also potentially accelerating organ dysfunction. Studies show that individuals with poorly controlled oral inflammation generally have elevated levels of inflammatory markers, which, over time, increase the risk of cardiovascular, metabolic, and neurological diseases. Therefore, managing oral biofilms is actually a crucial step in delaying aging and maintaining good health.
⑤ Digestive Diseases
The oral cavity is the entrance to the digestive system. When bacteria from biofilms enter the gastrointestinal tract with saliva, they can affect the balance of the gut microbiota. Some pathogenic bacteria can alter gastric acid secretion or irritate the gastric mucosa, thereby increasing the risk of gastritis, gastric ulcers, or Helicobacter pylori infection. Furthermore, oral flora imbalance can also affect intestinal barrier function through inflammatory mediators or immune signals, triggering chronic intestinal inflammation or indigestion. In other words, oral health is closely related to digestive system health, and poor biofilm control may be a potential source of chronic digestive problems.
⑥ Decreased Immunity
Long-term accumulation of oral biofilm continuously activates the immune system, leading to immune cell fatigue or a chronic low-grade inflammatory state. When the immune system is chronically under this "burden," its ability to defend against external pathogens decreases, making the body more susceptible to infections from pathogens in the respiratory tract, urinary tract, or skin. Furthermore, pathogens in the biofilm can also spread through the bloodstream, causing sepsis or other serious infections. In other words, neglecting oral hygiene may not only affect dental health but also increase the risk of systemic infections.
Many people believe that brushing their teeth thoroughly is enough to remove all bacteria from their mouths. However, from a medical perspective, the effectiveness of regular brushing in removing biofilm is actually limited.
First, brushing primarily works on the tooth surface, which can indeed effectively reduce some of the biofilm attached to teeth. However, the mouth is not just about teeth. The gums, tongue, upper and lower jaws, and inner walls of the mouth are also covered with biofilm. These areas have complex structures and are difficult for brush bristles to fully reach, allowing biofilm to remain stable and continue to release bacteria and inflammatory factors. In other words, even if teeth are thoroughly cleaned, the risks in other areas of the mouth are not truly eliminated.
Second, the oral environment changes rapidly after eating. The carbohydrates, proteins, and other nutrients from breakfast provide ample "energy" for bacteria remaining in the mouth, accelerating their reproduction and rebuilding a denser biofilm structure. Studies have shown that bacteria can reattach and form new biofilms shortly after eating, meaning that brushing only before breakfast cannot prevent biofilm growth throughout the day.
Therefore, from the perspective of oral microecology, simply relying on a regular brushing is unlikely to truly control the biofilm burden throughout the oral cavity. Our recommended oral cleaning order is:
Step 1: Complete oral care including brushing and full-mouth cleaning before breakfast.
After a night of bacterial growth, teeth, gums, tongue, upper and lower jaws, and the inner walls of the mouth are covered with an active biofilm. If you eat directly, these bacteria and their metabolic products may enter the digestive tract with food. First, clean the tooth surface with brushing; then use the Tongueclear oral cleaning airbag brush for a thorough and gentle cleaning of the mouth, restoring the oral environment to a relatively clean state before eating.
Step 2: Perform a full-mouth cleaning again after breakfast.
The sugars and nutrients from food cause residual bacteria to multiply rapidly and rebuild biofilms. Therefore, even if you have already cleaned after waking up, a second intervention after breakfast is still necessary.
At this time, you can use the Tongueclear oral cleaning airbag brush again for a gentle full-mouth cleaning to promptly remove food residue and newly formed bacterial deposits. Compared to repeated brushing, this method is gentler on tooth enamel and gums, while still covering key areas such as gums, tongue, upper and lower jaws, and the inner walls of the mouth, helping to maintain a longer-lasting feeling of freshness and oral health.
Many health changes don't start with grand decisions, but rather with seemingly small choices each morning.
A more complete oral hygiene routine may not bring immediate, dramatic changes, but it subtly alters the state of your mouth over time—a fresher breath, a more stable oral environment, a healthier overall health, and comfort that extends throughout the day.
When we truly understand the existence of oral biofilm and remove it in a more comprehensive, gentle, and consistent way, we're protecting not just our teeth, but a whole balance connected to diet, immunity, aging, and overall health. Health is never a one-time achievement, but a daily commitment to being taken seriously.
May every morning begin with a fresh breath;
And may this subtle yet steadfast protection accompany you towards a more relaxed and longer period of good health.
