While tooth cavities are not fun to deal with, they are more common than we think. According to the World Health Organization, dental cavities, also known as caries, are a major public health problem and the most widespread noncommunicable disease (NCD). 

It is also the most prevalent condition mentioned in the Global Burden of Disease Study 2015, ranked first for decay of permanent teeth and 12th for deciduous teeth.

A thorough understanding of any health or oral condition is the best way to treat it. It helps to simplify one's perceptions of a specific condition and better communicate one's concerns to the doctor or dentist. 

In this article, our orthodontists at the Invisalign Center have given a simple dental cavity classification to help better understand your condition when seeking medical attention. 

What is A Dental Cavity?

First, it is essential to understand what a cavity is. In simple terms, a dental cavity or caries is a hole that forms in a tooth due to decay. 

The primary cause of decay is the interaction between the bacteria in the mouth, sugary or starchy foods, and the enamel that coats the teeth. 

When the bacteria feed on the sugars, the starches are left on the tooth, producing acids that can erode the enamel, resulting in cavities. 

Importance of Dental Cavity Classification

Cavities are of many types. Determining the right type of cavity allows dental professionals to help narrow down the best treatment option. 

Dental cavity classification addresses the location, size, and depth of the cavity, which has a crucial influence on understanding the most suitable treatment approach. 

As with any dental condition, there is no one-size-fits-all approach to cavity treatments. This is where classification can be beneficial. 

GV Black Dental Cavity Classification 

Dental cavities are classified based on many criteria, specifically depth, location, and the number of surfaces involved. 

While dentists may use different approaches to classify cavities, the most widely used system is GV Black's dental cavity classification system. 

Dr. Black made numerous contributions to dental science and oral health during his career. Among these many contributions is the development of this system for classifying dental cavities. The term he used to classify was 'classes.'

Here is how this dental cavity classification is formed: 

‌Class I

This class refers to tooth decay that occurs on the surface of the tooth. It can be easily identified on the outlook. It usually forms on the chewing surfaces of the back teeth, like the molars and premolars, and causes decay on either the front or rear surfaces of the front teeth.

‌Class II

This class of cavity grows on the surface of the teeth between the molars and premolars. Due to their location and gum tissue, they are not easily visible to the dentist. They are located on the proximal surfaces of molars and premolars.

‌Class III

This decay starts on the surfaces between the front teeth. However, it does not cover the cutting edges of the teeth. Similar to Class II, this classification of the cavity is not visible.

They can be found on incisors and canines, but only where there is no angle to the teeth. They can also occur on the proximal surface of the front teeth.

‌Class IV

Just like Class III decay, this classification occurs on the surfaces between the front teeth, which covers the cutting edges of the teeth. More specifically, this cavity occurs on the biting surface of the incisors and canines.

‌Class V

These cavities grow on the front or back of either front or back teeth, closer to the gumline, on the "neck of the tooth." They occur on the proximal surfaces of incisors or canines, covering one or both of the incisal angles.

‌Class VI

This class of decay can be found on the top surfaces of the teeth. It can occur on either the incisal edges of the front teeth or the cusp tips of the back teeth.

They are cavities that grow in one of these locations - the gingival third of the labial, lingual, buccal, or palatal surfaces of any tooth.

When you go for a dental checkup, your dentist will use special instruments to detect soft spots on your teeth that are easily visible to the eye. In cases where they are not visible, your dentist will require current X-rays (or take new X-rays) to detect cavities.

Determining the Severity of Decay

The classification of decay is based on its extent and severity. It is generally classified into three ass incipient, moderate, advanced or severe. 

However, to better understand this classification and how it's determined, it is necessary to have a general knowledge of the components of tooth anatomy. 

The outer layer of a tooth is made up of "calcified enamel". It offers protection to the softer inner portion of the tooth, which is called dentin. Inside this dentin is what we call the pulp chamber, which is the innermost layer. It consists of nerves, blood vessels and connective tissue.

Using Dr. G.V. Black's system, orthodontists will evaluate tooth decay, basing how far the damage has penetrated through these layers of the teeth tissue:

Incipient Decay

This is when the cavities have gone less than halfway through the tooth's enamel. 

Moderate Decay

This decay occurs when the cavities go more than halfway through the enamel. However, they don't yet reach the dentin enamel junction (DEJ), which defines the boundary where the enamel meets the dentin.

Advanced Decay

As the word says, this is an advanced stage when the cavities spread through the DEJ but cover less than half the distance to the pulp chamber.

Severe Decay

This final stage is where the decay penetrates through the enamel and the dentin and covers more than half the distance to the pulp chamber.

Early detection of cavities and treatment of decay with filling can help prevent them from advancing to more serious or complex issues in the future. This is why it is highly recommended to not overlook the importance of regular dental checkups. 

In fact, this practice should be started in childhood at the early onset of teeth. Proper oral hygiene and discipline, such as brushing twice a day using proper techniques, can greatly prevent dental cavities.