What Causes Cavities? – Treatment & Prevention

Cavities in our teeth are the commonest dental diseases. Most of us have had at least one cavity throughout our lives. We often wonder the reasons behind cavities or tooth decay, even though we brush regularly and maintain good oral hygiene.

There could be internal as well as external factors, such as dry mouth, poor oral care, excessive consumption of sweet food, poor diet plan, etc., that leads to the formation of cavities


Let’s see various causes of cavities, how diet influences the prevalence of cavities, what are the stages of decay and how we can prevent it.

What causes cavities?

Multiple internal and external factors influence the process of tooth decay or the formation of a dental cavity. These factors are – the microbial flora of our mouth, the body’s defense system, saliva content, diet, and oral hygiene practices.

Consuming excessive sweet food, snacking in between meals and not brushing well are the main reasons for dental cavities. (1) The micro-organisms that cause tooth decay are streptococcus mutans, lactobacilli, etc.

Less saliva content can also indirectly influence cavity formation since saliva has anti-bacterial properties.

Some drugs like tetracyclines also promote demineralization. Similarly, medicines, which cause dry mouth, also contribute to tooth decay. (2)

It remains preliminary to ascertain whether cavity formation has any genetic predisposition.

Stages of tooth decay or caries

The process of tooth decay is a gradual one. Before you experience actual cavitation in your teeth, there will be initial stages of discoloration and demineralization.


This is the stage at which cavity is in the most incipient stage. The tooth involved will begin to show snowy or frosted appearance in the form of small white spots.

A dentist can identify these spots. This is the stage where the bacteria ferment the sugar in the food and begin the demineralization of the enamel. Demineralisation is a process where the calcium is removed from the enamel.

As the discoloration progresses, it may also turn yellowish or brownish. If you see your dentist at this stage, you might prevent cavities.

Enamel Decay

As the bacteria penetrate the enamel, it begins to break. Despite being the hardest substance in the body, enamel is extremely brittle.

As the enamel breaks, the demineralization advances and you may experience pain while biting or chipping off the tooth structure. The symptoms during this stage vary depending on the tooth involved and the microbial flora.

Dentinal Damage

As the protective enamel is damaged, the underlying dentin also becomes susceptible to bacterial invasion. At this stage, the pain increases, and sensitivity arises because of exposure of the dentinal tubules.

Significant cavitation will be there with incidences of food getting stuck and difficulty in keeping the area clean.

Pulp exposure

The pulp is the innermost layer of the tooth, having all the nerve fibers and blood vessels. Once the bacteria reach the pulp, the decay is significantly advanced, and you begin to experience severe pain and sensitivity.

Depending on the stage on inflammation of the pulp, you may have pain while lying down, or in reaction to hot or cold food. (3)

Periapical infection

From the pulp, the decay advances downwards around the root. You will have root caries and a periapical infection. This happens when you let the decay remain without any dental treatment.

At the apex of the root, there may be abscess formation. (4) At this stage, you may experience pus discharge or bleeding. A periapical abscess or cyst is detected radiographically.

Symptoms of dental caries


The most typical sign of caries is the pain. Many factors govern the nature, frequency, and intensity of pain. These include the extent of the infection, the tooth involved, diet, your oral hygiene and the condition of the surrounding tissues.

You may have pain only on biting or chewing something, or on lying down. On the other hand, some people may have spontaneous, unprovoked pain which subsides on its own.

Depending on the status of the pulp, cold food will either give you more pain or provide you with pain relief.

If the cavity is so severe that there is complete necrosis of the tooth, you may have no pain at all.

Food lodgement

As a tooth cavity forms, it makes a depression in the tooth surface or in between two teeth. This increases the chances of food being stuck in these crevices.

If the food is impinging between two teeth near the gums, you may have bleeding or pain in the gums. If the food keeps getting stuck in a cavity on the tooth, you will feel your tongue repeatedly moving there, and some discomfort is common.


The condition of having a foul smell from the mouth is called halitosis. When you have a cavitated tooth, there is an accumulation of food debris, bacteria, tartar, etc. in the cavity. (5)

However small this cavity is, it is confirmed that a lot of particles are stuck in there. Due to this, there is an unpleasant smell from your mouth which may not go even on repeated brushing or rinsing.

The smell may also be because of pus discharge from the area.

Pus discharge and Bleeding

If an abscess is present around the tooth or gums, there is likely to be pus discharge from the site. You may also experience some bleeding if the affected tooth is injured or you bite on something hard.

Sequelae of dental cavity

Tooth decay and cavitation can give rise to secondary conditions which occur mainly due to the weakening of the tooth structure because of cavity formation.

As a cavity is formed in the tooth, a significant amount of tooth structure is compromised. At such a time if you bite into something very hard, your tooth may fracture vertically. This happens because the enamel is worn off and the tooth becomes weak.

Due to the pain, you may be avoiding brushing in the area of the affected tooth. Consequently, that will cause an accumulation of plaque and Calculus around the tooth.

Your gums may begin to recede. If the periodontal status is already weak, your tooth can also start to become slightly loose from its socket.

Extraoral swelling

If the cavity is so widespread that the roots are also affected, and there is an abscess, you will have a swelling on the cheeks of the affected side.

Referred pain to the ear, forehead

In severe tooth decay cases, the pain spreads to the ear or even the forehead. Your maxillary sinus, which is the cavity next to your nose, may also feel heavy and painful to touch.

Treatment of dental cavity

The end goal of treatment is to get rid of the decay and replace the lost tooth structure. This is done by removing the decayed part of the tooth and then filling a restorative material in its place.

If you visit your dentist at the right time before there is irreversible damage, the dentist can prevent further decay before abscess formation occurs.

If the decay has reached deep into the pulp, a root canal treatment followed by crown capping is effective.

In severe cases when the cavitation is vast, and you lose a significant part of your crown, you may have to get your tooth removed and replaced by an implant or bridge.


There are multifactorial aspects to the formation of dental caries. Predictably then, there are multiple factors that you need to keep in check for their prevention too.

Maintenance of good oral hygiene

If you brush regularly, in the right manner and at the correct time, you dramatically reduce the chances of tooth decay. You can also use mouthwashes and floss as recommended by your dentist.

Make it a habit to clean your mouth after eating anything, especially sweet food.


Diet plays a critical role in cavity prevention. Sweets, candies and carbonated beverages are the leading foods that promote bacteria which cause decay.

If you modify your diet to reduce the consumption of these foods, you can prevent tooth decay.  Acidic foods also have the same effect. Make sure you don’t overeat sweet in between meals and at night.


Drinking fluoridated water or milk or brushing with a fluoride-containing toothpaste is also beneficial. (6)

Regular dental visits

As we read earlier, the dentist can diagnose a cavity much before it begins to penetrate deep into your tissues. If you see your dentist when the lesion is incipient, he/she can restore it and stop further damage.

However, you must supplement this by taking care of your diet and maintaining oral hygiene.

Final words

Major causes include sugar, carbonated drinks, and even genetics. Cavities are the most frequent dental problems.

But with a meticulous approach and slight diet modification, we can save our teeth from being damaged by bacteria. Timely treatment and maintenance of oral hygiene help us control tooth decay or dental caries.

Always remember the adage, prevention is better than cure.


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