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 became 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 is shifting 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:
    • cavitated lesions (where a hole has developed in the tooth that needs to be restored by operative intervention, such as a filling)
    • non-cavitated lesions (which can be helped by non-operative intervention and prevention, such as brushing with fluoride toothpaste)
    • active lesions (which indicate ongoing mineral loss, and can be helped by non-operative measures)
    • non-active lesions (which do not require intervention because biofilm metabolic activity is unlikely to lead to mineral loss).1
  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 caries lesions and recording changes in activity status or surface integrity is the only way to tell if caries is worsening or getting better. 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.