Dental Caries Classification Systems: An Overview

What Is the Role of Dental Caries Classification in Diagnosis and Treatment planning?

Dental caries is currently a globally prevalent chronic disease of the tooth enamel that eventually when left untreated or dentally or restoratively unaddressed, may progress to involve the vital tissues of the tooth, such as the pulp, causing tooth destruction and even resulting in tooth loss. Dental caries is hence, a complex multifactorial disease that is a combination of individual, biological, behavioral, as well as environmental factors, as defined in dental literature.

The clinical signs of dental carious lesions or caries are always of varying severity, ranging from the mild opacity in the enamel to deep or frank cavitation that can expose the second layer of dentin, below the tooth enamel. When this is left untreated, the dentinal caries progress to pulpal involvement requiring endodontic treatment or intervention.

Therefore, accurately diagnosing dental caries by the dental surgeon is hence, one of the cornerstones in dentistry for promoting an effective or strategic treatment plan, prevent disease progression, help support good patient outcomes, and also fulfill their esthetic,and functional expectations.

What Are the Main Classification Systems for Dental Caries?

Various classification methods have been proposed for categorizing dental caries, each system with its own advantages and limitations. Newer classification systems, such as the International Caries Detection and Assessment System (ICDAS) or the American Dental Association Caries Classification System (ADA CCS), have now been introduced as the new age models of classification. These systems have evolved from the traditional Black classification and also help dental practitioners protect the tooth surface from further bacterial or dental carious lesion invasion and extension.

Classification systems for dental caries are as follows:

1. G.V. Black Classification System:

The G.V. Black classification of dental caries lesions was first introduced in the year 1896, however, it is now outdated inspite of being considered the most influential classification system in the past century. This classification system is based upon categorizing the lesions based on the anatomical site of the lesion, divided into five classes of lesions with a sixth class of dental caries lesion that was later added.

In the G.V. Black classification,

• Class 1 - Caries refers to pit and fissure caries.

• Class 2 - Refers to posterior tooth caries.

• Class 3 - Refers to anterior tooth caries.

• Class 4 - Refers to anterior tooth caries involving the incisal edges.

• Class 5 - Refers to caries involving the cervical one-third of the tooth.

• Class 6 - Refers to the caries involving the cusp tips of posterior teeth and cuspids.

The G.V. Black classification system has a major drawback majorly because it was not designed to identify the initial lesions that occur prior to the mechanism of cavitation (cavity), or also it cannot classify the complex restorations that would need to be done for different carious lesions classified under this system itself.

2. Mount and Hume Classification System:

Mount and Hume caries classification system published many years later, was popular as well and is closer to the current international standards of dental caries classification. The Mount-Hume classification system incorporates the use of both fluoride as well as adhesive materials that were later introduced in dentistry in the 20th century.

In Mount and Hume classification,

• Site 1 - Refers to pit and fissure caries or minor exposed tooth surfaces on enamel.

• Site 2 - Caries that occur in the enamel surface closer to the contact areas and the proximal surfaces.

• Site 3 - Caries that involve the cervical areas (cervical one-third of the tooth).

• Size 0 - Refers to the early stage of demineralization.

• Size 1 - Refers to minimal enamel surface cavitations.

• Size 2 - Refers to dentinal cavitations.

• Size 3 - Refers to moderate lesions that are progressive and can lead to fracture of incisal edges or occlusal surfaces.

• Size 4 - Refers to extensive cavitation or bulk loss of tooth structure.

What Is the International Caries Detection and Assessment System?

In 2002, the expert international team comprised of world-renowned caries researchers, epidemiologists, and restorative dental surgeons tried to propose a new classification system globally for not only the categorization of dental caries lesions but also allowed the scope for practitioners to diagnose and decipher treatment plan for each class of dental caries.

ICDAS or International Caries Detection and Assessment System (initially the ICDAS) was then modified in 2005 to the ICDAS II which incorporates features of an individualized scoring system for detection as well as assessment of crown /coronal and root caries both.

Further, the added benefit of this system is even caries associated with restorations and sealants (CARS) can be detected. However, it is to be noted that root caries cannot be yet detected using this classification and currently epidemiological studies are being carried out to implement it in the future.

How Is the ICDAS System Implemented?

Implementing the ICDAS system requires two steps.

Step 1: The individual tooth surface (that is the different tooth surfaces - buccal, lingual or palatal, mesial, distal, and occlusal) is classified into the category of either sound, sealed, restored, crowned, or missing tooth.

Step 2: These are assigned a code from number 0 to 6 (zero to six) to every tooth surface of the carious tooth.

• Code 0 - This refers to the sound tooth surface with possible developmental defects, such as enamel hypoplasia (defective development of enamel) or dental fluorosis (condition resulting in white or brown speckles on the teeth), which would be the first visual sign of enamel caries.

• Code 1 - It differentiates between the occlusal dental caries and smooth surface carious lesions.

• Code 2 - These caries lesions are seen in enamel pits and fissures and are not only confined to this area specifically but would also possibly extend to the dentinal part of the enamel.

• Code 3 - Refers to the carious lesions that have progressed past the enamel exposing dentin, or producing a carious shadow in dentin.

• Code 4 - Refers to dental carious lesions that have evolved to affect dentin and can be clearly observed clinically as an underlying shadow.

• Code 5 - Refers to cavitations that have left a distinctive pattern affecting less than half of the enamel with the dentin exposed.

• Code 6 - Refers to dental caries that involve more than half of the tooth structure, considered an "extensive" cavitation.

Conclusion

Dental caries is one of the common globally prevalent conditions that continue to affect individuals oral health and have a negative impact on their systemic health as well. Dental practitioners have several adopted classification systems that can help not only in locating or diagnosing the caries, but also classification of caries is further an attempt to use the correct restorative material and the right mode of treatment to the dental patients .