Diagnostic Criteria

WHO Method
Numerous methods have been suggested for recording lesions and carious lesion activity. In the recent past, one of the most commonly used visual–tactile or visual criteria that have been used include the WHO method,10 which limits the assessment to one in which only cavitated lesions are recorded. The rationale for this approach was an assumption that reliable diagnosis of all non-cavitated lesions was unlikely. Because the focus is only on open cavities, it ignores the fact that non-operative interventions (such as fluoride) can help reduce caries risk by enabling reversal of the disease process through the remineralization process. Therefore, most dentists in developed countries today do not rely solely on this criterion.2,3

ICCMS™ and ICDAS Systems
The ICCMS™ approach. Over the past few decades, there was a clear awareness of 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. In addition, there was a recognized 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 were held with the goal of developing an international standard of diagnostic measurement and care. A key outcome of these efforts was the International Caries Classification and Management System (ICCMS™) a standardized method based on the current best approaches. 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.11

This system was designed 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.

In some respects, such as in the area of lesion activity assessments, the ICCMS™ system is a further evolution of several criteria systems that have been in place since the late 1990s.12 Other systems have also been incorporated into the new structure, whenever they represented the best thinking in a particular area.

The ICDAS System is an integral aspect of the ICCMS™ approach. While the ICCMS™ represents a new, enhanced approach to the diagnosis and management of caries, the ICDAS System provides a standardized method for assessing and tracking changes in caries activity. The ICDAS System was developed in 2002 (ICDAS I) and was later modified to ICDAS II in 2005.13 The ICDAS I and II criteria incorporate concepts from the research conducted by Ekstrand et al,14,15 Nyvad16 and other caries detection systems, as reported in the systematic review of Ismail and colleagues12 is broadly considered to be the most appropriate and reliable caries reporting system currently available. As a result, the ICDAS lesion evaluation criterion serves as the basis for determining the stages of the caries process and lesion activity for the purpose of caries management within the ICCMS™ approach.17

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.

For background, some of the measures of lesion activity that have been incorporated into ICDAS are based on previous studies that helped define key aspects of caries activity, such as ways to assess lesion depth, lesion activity, and considerations regarding root caries and recurrent caries.

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 and colleagues14,15 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 method, developed in 1999 by Nyvad et al,16 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.2,16

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.18

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.19 Diagnosis is accomplished using the Nyvad criteria in the lesion activity assessment section described previously.