For much of the last century, the diagnosis of dental caries entailed detecting only cavitation.1 Over the last few decades, however, the caries process has been recognized as a biofilm disease characterized by prolonged periods of low pH in the mouth leading to dissolution and net loss of minerals from the teeth. The demineralization of the teeth is now understood as a physiological continuum, and the understanding of caries shifted from a discrete episode of cavitation to an understanding of demineralization as a spectrum that ranges from microporosity to cavitation.2 Because the emphasis in dealing with caries has shifted from surgical repair to strategies that prevent decay, the challenge now to professionals is to provide better criteria for establishing the true state of a given tooth. Therefore, the primary purpose of caries diagnosis is to identify the biofilm disease process and also early signs of tooth demineralization in order to halt its progression.1,2,3

The scientific literature points to three main reasons why caries lesion diagnosis is important:

  1. To achieve the best health outcome for the patient by classifying caries lesions corresponding to the best management options for each lesion type. Lesions are currently classified in the following way:
    • non-active lesions (which do not require intervention because biofilm metabolic activity is unlikely to lead to mineral loss).1
    • non-cavitated lesions, which may be restored through the use of non-operative approaches, such as remineralization therapies (i.e. brushing with fluoridated toothpaste)
    • active lesions, which indicate ongoing mineral loss, and may be responsive to non-operative therapies
    • cavitated lesions, where a hole has developed in the tooth that requires restoration via surgical intervention, such as a filling.
  2. To inform the patient. The patient is the key in the management process because their cooperation is crucial in controlling the disease and slowing or reversing caries progression. Therefore, providing them with as much information as possible about the caries diagnosis is very important.1
  3. To monitor the clinical course of the disease. Long-term monitoring of all stages of caries lesions and recording changes in activity status or surface integrity is the only way to tell if caries is reversing or progressing. An active lesion that becomes inactive is a positive outcome, while active lesions that remain active reflect a lack of compliance or cooperation on the part of the patient, and professional intervention may be needed.1

What follows is a discussion of the different methods of caries lesion diagnosis and how diagnosis and management of the disease are intricately linked.

In the past, clinicians relied primarily on the use of caries measurement systems that relied solely on the assessment of the incidence and severity of cavitated lesions. As our knowledge of caries has matured, we now recognize that caries is a dynamic process, with the ability of non-cavitated lesions to either reverse (remineralization) or progress (demineralization), depending on the conditions occurring with each individual patient. Due to the ability of early lesions to reverse through the use of preventative therapies, such as the use of fluoridated toothpastes, mouthrinses or other remineralization therapies, it has become increasingly important to detect caries at the earliest stages possible, which maximizes the potential to maintain as much of the natural tooth as possible in the longer term.

More recently, significant efforts have been directed toward the development of comprehensive measurement systems that include assessment of caries across the continuum of the disease process, beginning with non-cavitated lesions. The most widely used system now available is the ICDAS System, an integrated system that includes all of the best understanding of caries to provide a standardized method for monitoring both the initiation and progression of caries across this continuum.