What Causes Tooth Decay? How To Detect and Prevent It

What is tooth decay?

Just found out you have a cavity? This can be a real bummer, as this can harm your oral health and add to more trips to your dentist for additional dental procedures. Tooth decay, or dental cavities, are areas where the outer surface of your teeth, also known as the tooth enamel, is broken down leaving holes in the affected teeth. Tooth decay can impact anyone of any age and has been a common chronic disease plaguing our society. Tooth decay can lead to a whole host of issues, ranging from gum recession, gum disease, tooth sensitivity, infection, and eventually tooth loss. If the tooth decay is left untreated, the cavities can continue to get larger and spread to deeper layers within the teeth. Sadly, once the outer layer of dental enamel is damaged, you cannot regenerate or gain it back. That’s why it’s extremely important to take care of your teeth because we only have what we start with once all of your permanent teeth have come into the mouth!

Stages of tooth decay

Tooth Decay and Causes


Dental enamel is known to be the hardest substance in the human body and is made up of lots of minerals keeping it strong, such as calcium and phosphate. When dental enamel becomes attacked by troublesome oral bacteria, the enamel loses its minerals. This can often be noted initially by the sign of white spot(s) on the surface of your teeth.

Enamel decay

As tooth decay progresses, the dental enamel will continue to be weakened. A color change is often noticed, turning from a white spot to a darker brown color.

Dentin decay

Underneath dental enamel is the dentin. The dentin makes up the majority of the tooth but is much softer than dental enamel. Once the tooth decay penetrates into the dentin, the decay begins to progress at a faster rate. Decay through the dentin is often accompanied by tooth sensitivity, especially when drinking and eating foods.

Pulp damage

Underneath the dentin is the innermost layer of the tooth, the pulp. Within the pulp lies the tooth’s nerves and blood vessels keeping the tooth alive and thriving. If tooth decay reaches the pulp, the sensation of pain is felt and the gums and face may begin to swell.


Progression of tooth decay into the pulp can cause pus to form creating a dental abscess. This stage is also characterized by increased inflammation and severe pain. A dental abscess can be life-threatening if left untreated, as the infection can spread into other areas of the head and neck. Individuals with a dental abscess may also experience a fever.

What causes tooth decay?

The main cause of tooth decay is dental plaque. When food particles and sugary substances contact your teeth when eating and drinking, a sticky film known as dental plaque begins to form. Dental plaque is made up of bacteria and other microorganisms which produce acids that cause your teeth to break down and decay. As the dental plaque remains on teeth it hardens and becomes known as calculus/tartar. Tartar is often a yellow/brown color and requires removal by a dental professional. Tartar can make it harder to remove new dental plaque and can continue the vicious cycle of tooth decay.

How do you know if your tooth is decaying: Signs and Symptoms

Initially, the signs and symptoms of tooth decay may not be present in the early stages. Common signs and symptoms of tooth decay include:

  • Spontaneous tooth pain
  • Tooth pain when eating or drinking cold or hot items
  • Tooth sensitivity
  • Noticeable holes in surfaces of teeth
  • Tooth discoloration (brown, black, yellow, white)
  • Pain when chewing


There are various treatment options for tooth decay which your dental professional will recommend depending on your specific oral condition. This includes:

  • Fluoride treatments such as in-office fluoride varnish and prescription fluoride toothpaste.
  • Dental fillings involve removing the tooth decay and restoring with a dental material such as a white composite filling or silver dental amalgam.
  • Root canal treatment, which typically is the treatment choice for teeth where the tooth decay has reached the dental pulp. The decayed pulp is removed and the root canal is cleaned and filled with dental material. Once the root canal is completed, a permanent filling or crown is needed to cover the tooth.
  • Extraction of severely infected teeth may be necessary if root canal treatment cannot fix the infection. Your dentist will inform you of the treatment options to replace the tooth/teeth needed to be extracted, such as a dental bridge, implant, or removable denture.

How to avoid tooth decay - Prevention

Practicing good oral hygiene is crucial for keeping a healthy mouth and preventing tooth decay. You should brush your teeth at least twice a day for two minutes each time. It is recommended to use a toothpaste containing fluoride, in addition to using an anti-bacterial mouth rinse containing fluoride. Flossing is important, too! Flossing is necessary to remove the food particles that get trapped in-between teeth and help prevent tooth decay from developing in those harder-to-reach areas.

Along with good oral hygiene practices at home, it is also essential to visit your dentist regularly for your check-ups and cleanings to detect tooth decay in the early stages. Your dental professional may recommend a dental sealant, which is a protective layer of filling material intended to prevent tooth decay by sealing off the food-trapping grooves of the chewing surfaces of the back teeth. Dental sealants are recommended by the Centers for Disease Control and Prevention (CDC) for all school-age children.

In addition, in-office fluoride treatments may be recommended. Fluoride is a mineral that has been found to help prevent tooth decay by neutralizing harmful acids and strengthening tooth enamel. Be sure you are consuming water regularly, as it is necessary to keep your oral health and overall health intact. Try not to consume too much-bottled water, as it is missing fluoride that is found in many public water sources.

Watching what foods and drinks you consume is also an important part of keeping your teeth healthy. Frequent snacking and sipping on sugary foods and drinks can increase the amount of time your teeth are exposed to damaging bacterial acids. Staying away from foods high in sugar can be beneficial to your teeth and body. Be sure you are getting the recommended amounts of foods from each food group.

Our doctors and dental specialists provide a wide range of dental services at our 40+ multi-specialty dental offices across Massachusetts and New Hampshire. Our dental team is compassionate, and our main goal is to provide you a comfortable, caring dental experience. Book an appointment at your local Gentle Dental today.