Diagnostic Criteria

Numerous methods have been suggested for recording lesions and carious lesion activity. Some of the most commonly used visual–tactile or visual criteria that have been used in the recent past include:

Recording cavitated lesions only. Working under the assumption that it is still not possible to reliably diagnose all non-cavitated lesions, the World Health Organization recommends that caries lesions be diagnosed at the level of cavitation only. This is done with the use of a probe.10 Because the focus is only on open cavities, it ignores the fact that non-operative interventions (such as fluoride) can help reduce caries risk and progression. Therefore, most dentists in developed countries today do not rely solely on this criterion.2,3

Recording both cavitated and non-cavitated lesions. In addition to taking note of cavitated lesions that can be helped by operative intervention, taking note of non-cavitated lesions (white spots that indicate where demineralization has occurred) can help the dentist observe where non-operative intervention might be useful. In 1988, Pitts and Fyffe11 devised the following diagnostic criteria that are still used today, and developed this method with the help of a mouth mirror and probe:

  • D1 (enamel lesion, no cavity)
  • D2 (enamel lesions, cavity)
  • D3 (dentin lesions, cavity)
  • D4 (dentin lesions, cavity to the pulp)

Lesion depth assessment. To understand the classification for lesion depth assessment, it is important to know how moisture on the tooth surface affects the visibility of a lesion. White spot lesions become more opaque in dried dental tissue compared to wet dental tissue because of increased light scattering. Typically, non-cavitated lesions that are visible on a wet tooth have penetrated deeply, while a non-cavitated lesion that is only visible after drying has penetrated less deeply into the tooth.

Based on these concepts, Ekstrand, et al12 suggested a visual, ranked scoring system for lesion depth assessment that is still commonly used. Using no probe, they examined tooth surfaces according to the following criteria:

  • no or slight change in enamel translucency after 5 seconds of air-drying
  • opacity or discoloration that is hardly visible on wet surfaces, but visible after 5 seconds of air drying
  • opacity or discoloration that is visible without air-drying
  • localized enamel breakdown with opaque or discolored enamel and/or grayish discoloration from underlying dentin
  • cavitation in opaque or discolored enamel exposing dentin

Lesion activity assessment. This is a newer diagnostic method, developed in 1999 by Nyvad et al,13 that focuses on the surface characteristics of lesions, namely activity as reflected in the surface texture of the lesion, and surface integrity, as indicated by the presence or absence of a cavity or microcavity in the surface. The rationale behind the method is that the surface characteristics of enamel change in response to changes in the biofilm covering the tooth surface. The diagnostic categories are as follows: active, non-cavitated; active, cavitated; inactive, non-cavitated; inactive, cavitated; filling; filling with active caries; filling with inactive caries.

  • Active, non-cavitated enamel caries lesions have a whitish/yellowish opaque surface, with a chalky or neon-white appearance, and the surface feels rough when a probe is moved across it.
  • Inactive, non-cavitated lesions, on the other hand, are shiny and can vary in color from white, brown, or black, and will feel smooth with gentle probing.
  • Active, cavitated lesions feel soft or leathery, while inactive, cavitated lesions are shiny and feel hard with probing.
  • In general, active, non-cavitated lesions have a higher risk of progressing to a cavity than inactive, non-cavitated lesions, which have a higher risk of becoming a cavity than healthy surfaces.2,13

Recording root-surface caries. This is a classification specific to root caries lesions that integrates activity assessment and surface integrity assessment. The diagnostic categories are as follows:

  • inactive lesion without surface destruction
  • inactive lesion with cavity formation
  • active lesion without surface destruction
  • active lesion with surface destruction (cavitation), but visually cavity does not exceed 1 mm in depth
  • active lesion with a cavity depth exceeding 1 mm, but does not involve pulp
  • lesion expected to penetrate into pulp
  • filling confined to root surface or extending from a coronal surface to root surface
  • filling with an inactive lesion (secondary) confined to the margin.14

Recording recurrent caries. This refers to caries at the margins of restorations, with recurrent caries reflecting the result of unsuccessful plaque control. These are typically found on the gingival margins of all classes of restorations, with the exception of class I restorations, which affect pit-and-fissure crevices on occlusal, buccal, and lingual surfaces of posterior teeth and lingual surfaces of anterior teeth.15 Diagnosis is accomplished using the Nyvad criteria in the lesion activity assessment section described previously.

The ICCMS™ approach. Over the past decade, there has been growing interest at the international level to develop a more holistic and updated approach to caries diagnosis and management. There is a clear awareness that there is an urgent need for a more robust, standardized method of classifying caries with a focus on more than just listing the various stages of the disease. There is a need for making sense of clinical trial results in systematic reviews and for aligning research outcomes with modern clinical caries measurement and management of caries.

Numerous meetings, workshops and conferences have been held with the goal of developing an international standard of diagnostic measurement and care. A key outcome of these efforts is the International Caries Classification and Management System (ICCMS™) a standardized method based on the best evidence currently available. This system, which is focused on improving long-term caries outcomes, combines history taking, clinical examination, risk assessment and personalized care planning at the individual patient level.16

A goal of the system is to develop a comprehensive care plan that incorporates:

  • Preventing caries initiation (primary prevention)
  • Preventive management of early caries (secondary prevention)
  • Tooth preserving operative plan (minimally invasive)
  • Review, monitoring and recall

This comprehensive care plan takes into account key risk factors for the individual patient, recommends inclusion of caries detection aids and lesion activity assessments and then lays out clear caries management strategies to obtain optimal results.

The ICCMS™ system represents a new, enhanced approach to the diagnosis and management of caries. In some respects, such as in the area of lesion activity assessments, the new system is a further evolution of several criteria systems that have been in place since the late 1990s.17 Other systems have also been incorporated into the new structure, whenever they represented the best thinking in a particular area. For example, the International Caries Detection and Assessment System (ICDAS), which was developed in 2002, is broadly considered to be a valid and reliable caries reporting system. For that reason, the ICDAS lesion evaluation criteria serve as the basis for determining the stages of the caries process and lesion activity for the purpose of caries management in the ICCMS™.18

The ICDAS criteria for visual examination and, when indicated, for radiographic examination, should be followed to assess the extent and severity of caries lesions. The ICDAS categories of caries lesion severity correlate well with histological depth of caries demineralization in both enamel and dentin. It should be noted that the histological depth of lesions correlates with demineralization but not necessarily with bacterial penetration.