Tooth Decay Symptoms, Causes & Treatment

What Causes Tooth Decay (Cavities)?

Tooth decay is damage to a tooth’s outer surface or enamel. This happens when bacteria in the mouth produce acids that break down enamel. Tooth decay leads to cavities or dental caries, or holes in the teeth.

Tooth decay is caused by acid-producing bacteria, especially Streptococcus mutans (S. mutans) bacteria. Decay happens when food is consumed and broken down into small particles. The bacteria in the mouth combine with the food particles and build up to produce a sticky film called dental plaque. The bacteria in dental plaque consume the sugars and starches in the food particles and produce acid. The acid dissolves the minerals in enamel, causing cavities.

Dental cavities (tooth decay) are widespread. On average, one in five people in the United States has untreated tooth decay. More than 80% of people will have had at least one cavity before the age of 34. Tooth decay is more likely to affect older adults, and nearly all adults aged 65 and older have had a cavity.

What Does a Cavity Look Like?

When a cavity is just forming, it may be impossible to detect. When tooth decay is very small and not seen clinically, it may be picked up on an x-ray between the teeth. It may appear as a darker shadow or a hole. When a cavity grows and becomes more severe, it will become a darker, larger shadow on the x-ray. 

If the cavity is visible, it will appear as a little white spot on the tooth in its initial stages. This indicates that the tooth is losing essential minerals that keep it strong and healthy. This process is called demineralization.

As cavity develops, it creates a discolored or dark spot on the tooth. Cavities come in different colors and shades, from white to grey to black and even yellow. They may also appear as a visible pit or hole in the tooth.

Many cavities may not have physical symptoms, which is why it is essential to practice prevention techniques, such as brushing and flossing twice daily and attending general dentist visits.

Symptoms of Tooth Decay

The common signs of tooth decay include:

• Bad breath
• Toothache or tooth pain
• Increased tooth sensitivity to sweets or hot or cold temperatures
• Gum disease or swelling or bleeding gums
• White or discolored stains on the surface of a tooth
• Visible holes or pits in a tooth
• A dental abscess which can cause fever, pain, and facial swelling
• Teeth that are easily chipped or fractured because of weakened enamel

6 Stages of Tooth Decay

There are six distinct stages of tooth decay, each more dangerous than the next. The following are the symptoms and signs of each stage: 

Stage One - Demineralization

Demineralization is when the minerals in the tooth enamel, primarily calcium, decrease. This occurs when acids produced by bacteria eat at the minerals in the outermost layer of the tooth. Demineralization may cause white spots to appear on the teeth. Demineralization can be reversed by maintaining proper at-home oral hygiene like brushing with fluoride toothpaste and flossing.

Stage Two - Enamel Decay

When the demineralization and remineralization process stops, enamel decay will occur and create a hole or sticky spot in the tooth. When this happens, white spots on a tooth darken to a brownish or yellowish color, sensitivity increases, and cavities form. Cavities must be filled by a dentist to prevent further complications.

Stage Three - Dentin Decay

When tooth decay progresses past enamel decay, it reaches the dentin, which is the tissue that lies under the enamel. Dentin contains tubes that lead to the tooth's nerves, which makes it more sensitive to acid damage. Because dentin is much softer than enamel, decay advances much quicker when it reaches this stage.

Stage Four - Pulp Damage

At this stage in the decay process, bacteria reach the pulp, which is the tooth's innermost level that contains nerves and blood vessels. At this stage, tooth decay can cause extreme tooth pain. The bacterial infection, if untreated, may cause an abscess to form.

Stage Five - Abscess

When tooth decay advances into the pulp, bacteria invade and cause an infection. The infection causes inflammation that creates an abscess or a pocket of pus at the bottom of the tooth. An abscess causes severe pain that can radiate into the jaw and cause swelling of the gums, face, or jaw, and a fever. An abscess requires immediate treatment to prevent the infection from spreading to the jaw, head, and neck.

Stage Six - Tooth Loss

If the tooth becomes too compromised from decay and infection, tooth extraction is the only option to prevent further damage.

Treatment for Tooth Decay

Here are the standard methods dentists use to treat tooth decay:

• Silver Diamine Fluoride is an antibacterial varnish that contains a higher level of fluoride than traditional treatments. It can be used for very small cavities to help remineralize the lesion and is used for patients who may not be cooperative for a traditional filling. 
• Dental fillings are used to treat typical cavities. A dentist removes the decayed tooth tissue and restores the tooth by filling it with a filling material such as composite resin, glass ionomer, or amalgam.
• A crown or “cap” is a covering made of gold, porcelain, or metal, used to repair and replace decayed or weakened areas of the tooth. It covers the entire tooth and provides more stability and support for teeth that have more severe tooth decay.
• A root canal is used when the nerve in a tooth dies from decay or injury. The pulp and decaying portions of the tooth are removed, and the roots are filled with sealing material. 
• Extraction (pulling the tooth) when the damage to the pulp cannot be fixed.

How to Prevent Tooth Decay

Tooth decay can be easily prevented and reversed if caught in the earliest stages. To prevent tooth decay, follow these best practices:

• Use an electric toothbrush to brush teeth thoroughly
• Use enough fluoride by brushing twice a day with an ADA-accredited fluoride toothpaste, drinking tap water with fluoride, and using a fluoride mouth rinse
• Prevent dry mouth by drinking enough water
• Always brush before bedtime, when saliva production, which protects teeth, is decreased
• Flossing daily to remove plaque
• Limit sugary foods, carbohydrates, and snacking
• Eat calcium-rich foods
• Avoid tobacco products
• Dental office visits twice yearly for regular check-ups and professional cleanings
• Dental sealants or plastic coatings are applied by dentists to prevent cavities from forming on the chewing surfaces on back teeth or molars

What Happens if Tooth Decay is Left Untreated?

Untreated tooth decay can lead to many uncomfortable physical consequences, including:

• Discomfort or pain
• Increased sensitivity
• Fractured tooth
• Infection or abscess
• Shifting of teeth
• Gum disease
• Tooth loss

These physical symptoms negatively impact lifestyle and cause problems with speaking, eating, working, and playing. In extreme cases, tooth decay may lead to death when an infection travels from the tooth to the brain.

Can I Remove Tooth Decay Myself?

This earliest stage of tooth decay, demineralization, can be reversed before permanent damage occurs. Using fluoride, which strengthens enamel, can reverse demineralization. Fluoride treatments include fluoride mouthwash, fluoride toothpaste, and drinking tap water that contains fluoride.

If tooth decay progresses past demineralization to enamel decay and cavities, it will require professional treatment from a dentist.