Dental Caries: Symptoms, Causes, Progression, & Treatment [with Pictures]

Dental caries, also known as tooth decay, is caused by bacteria in the oral cavity. Which, accumulates on tooth surfaces and produce acidic metabolites (mainly lactic acid) that damage the tooth enamel. In the beginning, dental caries is a pale or brownish spot on the tooth surface. Then, it turns later to a dark brown or black spot. If left untreated, It will continue to the dentin (the second layer in the tooth after tooth enamel) and eventually infects the tooth pulp. In the worst case, dental caries can lead to a dental abscess or tooth loss. If tooth enamel is intact and not damaged (in the early stage), dental caries can be reversed and treated by remineralization of tooth enamel. It can be prevented by:

  • Regular tooth brushing.
  • Fluoridation of teeth.
  • Regular dental check-ups.
  • Eating a healthy diet.

Dental Caries Prevalence

Dental caries (tooth decay) is one of the most common diseases in the world and occurs with a high incidence in industrialized countries. In the early phases of human history, it is hardly noticed. A change in the diet of industrially advanced countries in the 19th century led to a sharp increase in dental caries rate. Almost everyone is affected once in his life by caries. The finer the food preparation and a lower proportion of hard food components ensure that occlusal surface and notches in the tooth surface (pits and fissures) are susceptible to tooth decay. Also, it affects the cervical region and between teeth. Today, caries occurs more in the child’s primary teeth and tooth root in older people.

Dental Caries Formation

Dental caries bacteria decompose sugar from food debris and produce acidic metabolites (mainly lactic acid) which destroy the tooth enamel. The tooth enamel is exposed constantly to two processes:

  • Demineralization: bacteria decompose sugar and produce acids in the oral cavity which decrease the oral pH and create an acidic environment. In response calcium and phosphate ions diffuse out the tooth enamel, resulting in demineralization. (pH is a measure of the acidic or basic character of an aqueous solution. Solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic).
  • Remineralization: When the pH rises again, the tooth enamel restores calcium and phosphate from saliva (The process is reversed).

Dental caries is a dynamic process characterized by episodic demineralization and remineralization. Any alteration in the balance of these dynamic processes can cause caries which leads to tooth enamel damage.

Tooth Anatomy
Tooth Anatomy

Dental Caries Symptoms

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Dental caries (tooth decay) is progressive tooth destruction. It can affect single tooth or several teeth. Caries symptoms depend on the stage. In the early stage, superficial changes in tooth enamel. In the advanced stage, a visible cavity found on the tooth surface.

Early Stage

Dental caries at the beginning is barely visible. You may find white spots on the tooth surface. These white spots are solved minerals from tooth enamel. The Early stage of caries can be reversed by regular tooth brushing to remove caries bacteria and using a fluoride toothpaste to replace mineral loss from the tooth surface. With poor oral hygiene, the progression of dental caries begins. White spots on the tooth enamel turn to cavities and you may experience pain for the first time. But pain occurs when nerves of the tooth are attacked by bacteria. At the early stage of dental caries, teeth react very sensitively to cold or high sugar foods.

Late Stage

Without treatment, dental caries progressing slowly and the pain increases. Untreated caries is very dangerous and can cause a dental abscess or even tooth loss. Caries bacteria can travel through the bloodstream to the entire body and spread to other organs.

Secondary Caries

Dental caries treatment (Tooth filling or Dental crown) does not guarantee that you are protected from caries. With poor oral hygiene, teeth often develop a so-called secondary caries. It is formed in several years at the interface between the tooth and the filling or crown. This too small area is large enough to allow the microscopic bacteria to grow. Secondary caries may be the reason of loose or lost tooth fillings, a lasting or a recurrent toothache, and tooth sensitivity with sweet, hot or cold foods and drinks. However, these symptoms occur in the late stage of dental caries.

Stages of dental caries

Dental Caries Causes

Dental caries (tooth decay) is a multifactorial process that is caused by several factors. These factors are:

  • Bacteria: they decompose carbohydrates and produce acidic metabolites that attack tooth enamel.
  • Carbohydrate: it provides the basis of life for bacteria.
  • Poor oral hygiene: lack of dental care promotes bacterial growth, proliferation and the formation of plaque.

When sugary food sticks or accumulates on the tooth surface. Oral bacteria decompose sugar and produce acidic metabolites that attack the tooth enamel and promote the development of caries. Dental caries is not hereditary. However, it can occur frequently in families whose members have a “caries-prone” tooth form, for example, deep tooth fissure. Also, oral hygiene and bad eating habits can lead to a frequent occurrence of dental caries within a family.

Causes of dental caries
Causes of dental caries


The amount and composition of saliva influence the spread of dental caries. Saliva softens the food, so it makes the removal of food debris easier. The saliva:

  • Neutralizes the acid produced by bacteria.
  • Decreases plaque accumulation.
  • Aids in the removal of food debris.
  • Promotes the remineralization by acting as a reservoir of calcium, phosphate and fluoride ions.
  • Has an antibacterial action.

If you can’t brush your teeth after eating. You can chew a sugar-free gum with sugar substitute xylitol. Chewing a sugar-free gum stimulates saliva production and may partially neutralize the acid produced by bacteria.

Dental Caries Risk Factors

Dental caries (tooth decay) is influenced by several factors: bacteria, oral hygiene, and eating habits. In the oral cavity, there are more than 700 types of bacteria. These microorganisms are needed for a healthy oral flora. Some bacteria feed on sugar and produce acidic metabolites. These acids attack the tooth enamel, causing caries. The following factors increase the risk of dental caries:

  • Poor oral hygiene: irregular toothbrushing and flossing, especially after eating and drinking will lead to plaque accumulation on tooth surfaces, gumline and in interdental spaces.
  • Dry mouth: saliva protects your teeth against dental caries by washing away bacteria and food debris. Saliva has an antibacterial effect and buffering effect that reduce the level of acids produced by oral bacteria. Also, it contains minerals (calcium, phosphate and fluoride ions) that can reverse early-stage caries (Remineralization). Low salivary flow will increase the risk of dental caries.
  • Some foods and drinks: dental caries formation is promoted by sugary foods and drinks. Carbohydrates provide a good environment for bacterial growth. Oral bacteria decompose sugar and produce acidic metabolites that damage the tooth enamel.
  • Smoking: smoking or chewing tobacco promotes dry mouth condition (xerostomia), causing tooth decay.
  • Some diseases: anorexia, bulimia, heartburn or gastroesophageal reflux disease, can cause acid to flow into the oral cavity causing tooth erosion and dental caries.

Dental Caries Complications

In the early stage, dental caries (tooth decay) affects only tooth enamel. Untreated caries creates a cavity in the tooth enamel, which can spread to the dentin (the second layer of the tooth after enamel) and eventually reach the tooth pulp (contains nerves and blood supply). It can cause serious and lasting complications, such as:

  • Severe pain.
  • A dental abscess.
  • Tooth fracture.
  • Eating problems.
  • Tooth loss.

Also, tooth decay bacteria can:

  • Enter the bloodstream, causing blood poisoning (sepsis).
  • Spread to the soft tissue, causing facial cellulitis and Ludwig’s angina.
  • Spread to the bone of the jaw, causing osteomyelitis.
  • Reach the heart via the bloodstream, causing endocarditis.

Dental Caries Diagnosis

Your dentist will examine your oral cavity with mirror, probe, and x-ray, searching for evidence of dental caries. It is often very difficult to detect caries in the early stage. Your dentist may detect cavities in the tooth enamel extending to the pulp in the late stage. Treatment options depend on the diagnosis (the position and extension of tooth decay). Dental caries is not hereditary but occurs frequently in a family. This is probably due to similar eating and oral hygiene habits in the family.

Dental Caries Treatment

The treatment depends on dental caries (tooth decay) position and extension. the dentist has various ways to remove it and restore the tooth shape and function.

Early Stage

In the early stage of caries, there is white spots and no cavities on tooth surfaces. In this stage, dental caries can be reversed. For that, you should improve your oral hygiene and change your eating habits. People who consume large amounts of sugary foods and drinks (such as sweets, soft drinks, and juices), have an increased risk that dental caries will continue to spread and cavities will occur on tooth surfaces. So brush your teeth regularly with fluoride toothpaste to promote “Remineralization”. And chew sugar-free gum to stimulate the salivary flow that flushes out bacteria and food debris and neutralize acids that are produced by oral bacteria. Also, you should visit your dentist for professional cleaning and the removal of dental plaque. In the early stage of caries, regular professional fluoridation is recommended to reverse tooth decay “Remineralization”. The dentist will remove the dental plaque and calculus and will apply fluoride varnish to the affected areas.

Late Stage

Late stage caries treatment, depends on where and how far it has already progressed. In most cases, the dental drill is used to remove bacteria from cavities. The treatment is performed under local anesthesia.

  • Dental fillings: also known as “Dental restorations” such as amalgam, composite resin, and ceramics. The dentist will remove dental caries by the drill under local anesthesia. To remove bacteria and prevent its progress. Dental fillings are used to restore tooth shape and function.
  • Root canal treatment: if dental caries bacteria spread to the tooth pulp, you will need a root canal treatment to remove bacteria from roots and to prevent a dental abscess. Root canal treatment is used to save a badly damaged tooth and prevent its extraction.
  • Dental crown: if the tooth becomes weak, you will need a dental crown. It is recommended in a tooth with large restoration and after root canal treatment to protect the tooth and restore its shape and function.
  • Tooth extraction: if the tooth is severely damaged and can’t be restored with dental fillings or dental crown, it must be extracted.

Dental Caries Prevention

You can prevent dental caries by following a few habits every day, mainly oral hygiene and eating habits. Complete removal of dental plaque by regular teeth cleaning is the most effective way to get healthy teeth and gums.

  • Regular tooth brushing: at least twice a day, following the correct brushing technique.
  • Dental floss: use dental floss and interdental brushes to remove plaque in the interdental spaces and along the gumline.
  • Fluoride: gel, toothpaste, and mouthwash with fluoride make your teeth stronger and more resistant to dental caries. Visit your dentist to know, what is the appropriate amount of fluoride for you.
  • Healthy diet: eat a varied diet with plenty of vegetables and fruits, to clean your teeth naturally.
  • Reduce the consumption of sugary foods and drinks: foods and drinks that contain a large amount of sugar are bacteria’s food source. Bacteria decompose sugar and produce acidic metabolites that attack the tooth enamel, causing dental caries.
  • Drink plenty of water: to keep your oral cavity moist, wash your teeth from bacteria and food debris, and neutralize bacterial acids.
  • Chew sugar-free gum: to stimulate the flow of saliva and inhibit dental caries bacteria.
  • Visit your dentist: at least twice a year for professional cleaning and examination. The sooner dental caries is detected, the better the prognosis.
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