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How Do Cavities Form?

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How Do Cavities Form?

Cavities often conjure up feelings of dread and concern. Cavities are prevalent dental issues affecting individuals of all ages. Understanding how cavities form is crucial for maintaining optimal oral health and preventing their onset.

Cavities, also known as tooth decay, develop when bacteria present in plaque produce acids that attack the tooth enamel and cause holes. Dietary habits and oral hygiene practices, including regular dental exams and cleanings, can help prevent cavities. 

The Tooth Structure & Cavities

Every tooth has an outermost layer, the enamel or the hardest tissue in the body. Beneath the enamel lies the dentin and, at the core, the pulp, which houses nerves and blood vessels.

A cavity begins with a film that’s constantly in your mouth—dental plaque. Plaque is a sticky biofilm made of bacteria that can affect the health of your teeth if not kept in check. When you consume sugary foods and drinks, the bacteria feast on these sugars, mix with the saliva in your mouth, and produce acids as a byproduct. These acids then start breaking down the minerals in your teeth, potentially leading to tooth decay or cavities. 

Stages of Cavity Formation

The formation of a cavity is a slow and steady process with 5 distinguishable stages, each more threatening to your oral health than the last.

Stage 1: Initial Demineralization

The first stage of cavity formation is the demineralization of the tooth enamel. Acids created by bacterial metabolization of sugars weaken and remove the minerals in the enamel, leaving it vulnerable to decay. This stage is reversible with proper oral care, as minerals from your saliva can actually help to remineralize the enamel. 

Stage 2: Enamel Breakdown

When the enamel is consistently exposed to acids and sugars, it starts to break down, creating a pit in the tooth. In this stage, the telltale sign of a cavity is usually a visible hole in the tooth that begins to develop.

Stage 3: Dentin Decay

If left untreated, a cavity will progress to the dentin, the softer, yellow tissue beneath the enamel. At this point, you may experience symptoms such as pain or sensitivity to hot, cold, or sweet foods and drinks.

Stage 4: Pulp Involvement

The fourth stage is pulp damage, when decay reaches the tooth pulp, which is where the nerves and blood vessels reside. When decay reaches the pulp, it causes swelling and irritation, potentially leading to pain.

Stage 5: Abcess

As tooth decay advances into the pulp, it can lead to infection and pain radiating into the jaw if not treated promptly. Inflammation in the tooth can lead to pus-forming or a tooth abscess. 

Symptoms of a stage 5 cavity can include pain, swelling of the gums or face, fever, and swollen lymph nodes in the neck. Treatment for a cavity this advanced may require the removal of the affected tooth. 

Signs of a Cavity

The earliest sign of a cavity is often a white spot on the tooth, indicating mineral loss. If the decay progresses, you can feel it as a toothache, tooth sensitivity, pain when biting down, and visible holes or pits in the teeth. Cavities can also appear as brown or black spots on the teeth. 

Factors Contributing to Cavities

Several factors can increase your likelihood of developing cavities.

Poor Oral Hygiene

Neglecting to brush and floss regularly allows plaque to accumulate and bacteria to thrive. This, in turn, increases the production of acids that can damage enamel.

Receding Gums

Receding gums, caused by hard brushing or age, make the tooth root more susceptible to plaque formation and decay. Tooth roots are also not protected by enamel and are more likely to get cavities. 


Frequent consumption of sugary and starchy foods and drinks provides ample fuel for cavity-causing bacteria. Frequent snacking also allows food more time to damage the teeth. 

Acidic Foods

Acidic foods and drinks, such as sodas, citrus fruits, and coffee, can erode enamel, making cavities more likely to form.

Lack of Fluoride

Fluoride is crucial for preventing cavities. It strengthens tooth enamel and can even reverse early-stage decay.

Prevention & Treatment of Cavities

Your dentist can treat a cavity with a filling. Here are the measures to fortify your efforts against tooth decay.

Regular Brushing & Flossing

Maintaining a rigorous oral hygiene routine is the first line of defence. Brushing at least twice daily with fluoride toothpaste and flossing at least once daily can help prevent cavities. 

Dental Visits & Cleanings

Regular dental check-ups and professional cleanings are vital. Your dentist can identify and treat cavities early before you notice a problem or they grow larger and cause pain and sensitivity. 

Fluoride Use & Sealants

Supplementing your oral care routine with fluoride treatments and dental sealants can provide an added layer of protection.

Dietary Adjustments

Limiting the consumption of sugary and acidic foods can significantly reduce your risk of developing cavities.

Preventative Measures for Healthy Teeth & Gums

Cavities may seem like a minor inconvenience, but if left untreated, they can lead to serious dental issues. Often, early cavities present with no symptoms, making regular dental exams and cleanings crucial for detecting and treating them at their earliest stages. With the help of X-rays, your dentist can identify cavities before they become more severe and potentially lead to tooth loss. Don’t wait for a dental issue to strike. Book an appointment with Dentistry on Danforth today. 

Written by Dr. Kostas Papadopoulos

Dr. Kostas Papadopoulos received his Doctor of Dental Surgery degree from the University of Toronto in 1992 after completing 3 years of biochemistry and the 4-year program in dentistry. He enjoys continuing education and has attended numerous rehabilitative and cosmetic dentistry programs, including courses taught by Dr. John Kois.

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