Diagnostic Criteria

WHO Method

Numerous methods have been suggested for recording lesions and carious lesion activity. In the past, one of the most commonly used visual–tactile or visual criteria that have been used include the WHO method,²⁶ 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.^11,15

ICCMS™ and ICDAS Systems

The ICCMS™ approach. Over the past few decades, there was a growing recognition of the need for a more standardized and robust method for classifying dental caries—one that extends beyond merely categorizing disease stages. Additionally, a systematic approach was needed to interpret clinical trial results in systematic reviews and align research outcomes with modern caries measurement and management practices. To address these challenges, numerous meetings, workshops, and conferences were held to develop an internationally accepted standard for diagnostic measurement and patient 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.²⁷

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 (Ensuring long-term disease control through recall and follow-up)

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 certain aspects, such as lesion activity assessments, the ICCMS™ represents an evolution of several classification systems that have been in use since the late 1990s.²⁸ Additionally, other established systems have been integrated into the ICCMS™ framework whenever they reflected the most effective approaches in their respective areas. 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 2005.²⁹ The ICDAS I and II criteria incorporate concepts from the research conducted by Ekstrand et al, ^30,31 Nyvad³² and other caries detection systems, as reported in the systematic review of Ismail and colleagues⁸ 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.³³

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 is important to note that the histological depth of lesions correlates with demineralization but not necessarily with bacterial penetration.

To provide context, several of the measures used to evaluate lesion activity in ICDAS are derived from earlier research that identified key factors influencing caries activity. These include methods for assessing lesion depth, activity, as well as considerations for root caries and recurrent lesions.

Lesion depth assessment. When assessing lesion depth, it's essential to understand the effect of moisture on the tooth surface. White spot lesions appear more opaque when the dental tissue is dry, due to increased light scattering. Generally, non-cavitated lesions visible on a wet tooth have progressed further, while those only visible after drying are typically less advanced.

Based on these concepts, Ekstrand and colleagues^30,31 suggested a visual, ranked scoring system for lesion depth assessment that is still commonly used. Without using a 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 barely visible on wet surfaces, but becomes visible after 5 seconds of air-drying

• opacity or discoloration that is clearly visible without the need for air-drying

• localized enamel breakdown with opaque or discolored enamel, and/or grayish discoloration from the underlying dentin

• cavitation in opaque or discolored enamel exposing dentin.

Lesion activity assessment. This method, developed in 1999 by Nyvad et al,³² emphasizes evaluating the surface characteristics of lesions, particularly their activity as indicated by surface texture, and surface integrity, which is determined by the presence or absence of cavities or microcavities. The rationale behind this approach 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.^11,32

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.³⁴

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.³⁵ It is essential to distinguish between recurrent caries and stained margins on resin-based composite restorations.³⁵ Diagnosis is accomplished using the Nyvad criteria in the lesion activity assessment section described previously.