What you need to know about the 3 main types of tooth decay

tooth decay types

What is tooth decay?

Tooth decay is a common disease that affects the hard tissues, particularly the minerals that made up the tooth. The tooth is covered by two layers: enamel and dentin.
The tooth decay process starts with the enamel, the outermost layer, then progresses to the dentin, to finally reach the pulp. It can affect the teeth of both children and adults.
The type of dental caries depends on its extent and location on the tooth surface.

The different types of tooth decay:

Caries can affect different areas of the tooth: chewing surfaces, between the teeth, and near the gum line area. Besides the location on the tooth itself, the lesions can affect different teeth: the incisors, canines, premolars, and molars.

The location and extent of the cavities say a lot about your oral hygiene routine and diet. It also determines the kind of treatment you will need.

Chewing surfaces cavities:

It is the most common type of cavity and involves only the back teeth (molars and premolars). The chewing surfaces contain crevices and grooves that trap bacteria and food debris and make toothbrushing and cleaning harder.
As a result, bacteria will overgrow, leading to tissue destruction and cavities.
Caries in chewing surfaces can go unnoticed until you suddenly feel pain.


In children with deep tooth grooves, a sealant can be applied in this area to prevent bacteria from penetrating and proliferating.
In adults, the only way to prevent this type of decay is to maintain good oral hygiene and visit your dentist regularly every six months for a check-up and a professional cleaning.
It is also recommended to use additional oral hygiene means, such as fluorinated mouthwash, to prevent plaque formation and strengthen your teeth.


Treatment depends on the extent of the lesions. If the decay is limited to the enamel, your dentist can reverse the lesion by applying a fluoridated varnish. Fluoride helps to remineralize the tooth, in other words, to bring back the minerals it has lost. At this stage, this is the most conservative treatment method.
However, if the decay has progressed deeper, forming a cavity, your dentist needs first to remove the decayed tissues. Then, he will fill the tooth with dental material.
A root canal or extraction may be necessary if the tooth nerve is affected.

Interdental cavities:

They involve the areas between the teeth. Tooth decay can occur in these specific areas because the toothbrush bristles do not reach them. As a result, plaque and food debris will accumulate, leading to a cavity.
People with dental crowding are more likely to be affected, as it promotes food retention even more.


The only way to prevent interdental cavities is to floss daily or use an interdental brush. It may seem hard at first but you will quickly get into the habit as you notice the benefits.
Regular visits to your dentist are also crucial because only X-rays can identify these types of lesions.


The treatment consists of removing the decayed tissues, then restoring the interdental spaces with a filling.
Pulp infection or extensive damage may require a root canal treatment or extraction.

Tooth decay near the gum line area:

Commonly seen in the elderly, this tooth decay type appears near the gum line and may also involve the roots. When it occurs, it rapidly progresses deeper because the enamel in this area is thinner.
Root decay occurs especially following a gum recessing. When gums recede, they expose the root dentin, which is less resistant and more susceptible to decay.


Maintain good oral hygiene by brushing your teeth regularly and properly. Do not apply too much pressure or use a hard bristle toothbrush, as this can cause gum recession and tooth wear.
Seek professional dental cleanings on a regular basis to remove tartar and any buildup.
Consider using fluoride supplements, such as mouthwashes, varnishes, and gels, to strengthen and remineralize your teeth.


This type of tooth decay progress rapidly. If left untreated, it can reach the pulp requiring root canal treatment. If caught earlier, your dentist will remove the lesion, clean your teeth and restore them with a filling.

Tooth decay in children and adolescent:

According to a CDC report:
  • More than half of children aged 6 to 8 have had a cavity in at least one of their baby (primary) teeth.
  • More than half of adolescents aged 12 to 19 have had a cavity in at least one of their permanent teeth.

Baby teeth are temporary and destined to be replaced by permanent teeth. When permanent teeth first appear, they are immature because they are not yet fully developed. They will gradually complete their growth and maturation over the next few years.

Baby and immature permanent teeth are more likely to be affected by the three types of tooth decay. This is due to the low resistance of their hard tissues (enamel and dentine). Cavities then tend to progress rapidly toward the pulp.

Caries can also occur in areas that are usually less likely to be affected, including smooth surfaces. This is the least common form of decay and can affect the front surfaces of any tooth.

When it affects baby teeth (especially children under the age of 6), it can progress rapidly and extensively, destroying the entire visible portion of the teeth.

What other conditions can affect our teeth?

Tooth decay is not the only thing that can damage our teeth. Other dental conditions can also do so, including:
  • Tooth wear: It’s a condition that leads to enamel and dentin breakdown without involving bacteria. Dental wear often occurs as a result of mechanical irritation, such as rough tooth brushing or the use of a hard-bristled toothbrush. High acidity in the mouth can also lead to a form of dental wear known as erosion.
  • Tooth discoloration: It causes a change in the natural tooth shade or may appear as scattered stains on teeth surfaces. It can be due to excessive consumption of pigmented foods (such as coffee, tea, and red wine) or other factors such as taking certain medications, ingestion of large doses of fluoride during tooth development, trauma, or aging. The treatment can vary from a whitening procedure to a restoration with a crown or veneers.