Dental Caries

Dental Caries

Dental caries is the most common disease or disorder occurring in the oral cavity. The microorganisms along with the food particles present in the mouth leads to dental caries. It is also known as “Tooth Decay” or “Cavities”. This disease can lead to pain, infection, and even tooth loss.

Normal Tooth Anatomy

A tooth has two main parts: a crown portion and a root portion.

The difference parts of the tooth consist of:

  • Crown
  • Root
  • Crown is the part of the tooth which is seen in the mouth.
  • Root is the part of the tooth which is inside the jaw bone.

The different parts of a tooth consist of:

  • Enamel
  • Dentin
  • Cementum
  • Pulp


Enamel is the highly mineralized and hard outer substance of the tooth. Its colour varies from light yellow to grayish white.


Dentin is that part of the tooth which is present between enamel or cementum and pulp chamber. It is softer than enamel and therefore decays more rapidly.


Cementum is a bony substance covering the root of the tooth. Its colour is yellowish and is softer than dentin or enamel. The main function of cementum is to serve as a medium for periodontal ligament to attach to the tooth for stability.


The dental pulp is the centre portion of the tooth. It is filled with soft connective tissue which contains blood vessels and nerves .It is commonly called the “nerve of the tooth”.

What is Caries?

Dental Caries is an infectious disease caused by microorganisms or bacteria which destroys the tooth structure leading to cavities.

Types of Caries

Caries may form on the different surfaces of a tooth. Caries can occur on: the chewing surface, tooth surface next to cheek, in between teeth, near the gum line, or root if it is exposed. Types of Caries include the following:

Dentinal Caries

Cementum Caries: Caries formed on the roots of teeth

Recurrent Caries: Caries that appear on the tooth surface with previous history of caries

Incipient Caries: Caries that appears on the surface that has no previous caries

Baby Bottle Caries: This type of caries is seen in young children with baby teeth

Caries which extends to the dentin layer

Signs & Symptoms

When a cavity is just beginning there may not be any symptoms at all. As the decay gets larger, however, it may cause signs and symptoms. The earliest sign of caries is the appearance of a chalky white spot on the surface of tooth. Other signs and symptoms can include:

  • Tooth ache
  • Tooth sensitivity
  • Mild to sharp pain when you eat or drink something sweet, hot or cold
  • Visible holes
  • Pain when you bite down
  • Red and swollen gums
  • Bleeding gums
  • Pus around your teeth and gums
  • Bad taste in your mouth
  • Loose teeth
  • Pain that causes you to avoid brushing or cleaning certain teeth or areas

Causes of Dental Caries

Why do dental cavities happen?

Dental caries are caused by:

  • Bacteria
  • Diet
  • Pregnancy and Nursing
  • Bacteria
  • Streptococcus mutants and Lactobacilli are believed to cause dental caries.
  • Diet
  • Eating foods rich in sugar raises the risk of acid production, which damages tooth enamel. Plaque build-up after consumption of acid promoting foods erodes teeth to create tooth cavity.

Pregnancy and Nursing

As hormone levels change during these periods, saliva is increased, thus raising the amount of plaque and bacteria in the mouth.

Risk Factors

Eating foods rich in sugar raises the risk of acid production, which damages tooth enamel. Plaque buildup after consumption of acid promoting foods erodes teeth to create tooth cavity.

  • Intake of heavily sugared drinks
  • Reduced saliva production
  • Weak dental fillings
  • Receding gums
  • Older age
  • Poor oral hygiene


Dental caries can be diagnosed based on Clinical Inspection:

  • Inspection of visible tooth surfaces with the aid of a dental explorer
  • The surface of the tooth may be soft when probed with a sharp instrument.
  • Early caries is often diagnosed by blowing air across the suspect
  • Radiographs: Dental X-rays shows caries particularly between the teeth.


The main goal of treatment is to preserve tooth structures and prevent further destruction of the tooth. Early treatment is less painful and less expensive.

Caries is removed with the help of a dental hand piece, and then the remaining tooth structure is restored.

When the decay is too extensive, there may not be enough tooth structure remaining to allow a restorative material to be placed. In such cases, a crown is placed. A crown is a cap made of metal, gold or porcelain that is fitted over the natural crown of the tooth. If the caries is too deep, the tooth dies of infection, and then root canal treatment is required.

Extraction is required if the carious tooth cannot be saved.


Prevention of dental caries is easier, less expensive and less painful than treatment. Prevention involves good oral hygiene, dietary management, and other measures.

Oral Health

Proper brushing and flossing

Use of inter-dental brushes, water picks, and mouthwashes

Regular dental examinations & cleanings


Limiting the frequency of consumption of sugar

Avoiding sticky foods such as chocolates

Other Preventive Measures

Use of low intensity laser radiations of argon ion

Currently there is ongoing research to find a vaccine for dental caries.

Use of sealants: Sealants are a thin plastic-like coating which is applied to the tooth surface to prevent food from being trapped inside the surface of tooth. Use of calcium and fluoride supplements

While prevention is best, early treatment of dental caries is less expensive and less painful than delaying treatment. Prognosis is good if the disease is treated early. If untreated, caries is a major cause of tooth loss.