Diagnostic tools and measurements--impact on appropriate care.

The diagnosis of primary coronal caries should be seen as a complex process, comprising both detection and measurement phases, which enables clinicians, researchers and epidemiologists to make informed decisions about the management and prognosis of the disease process. The different diagnostic thresholds employed for measurements of caries experience can be viewed as an iceberg, a metaphor which demonstrates the ambiguity of the term "caries free" and which can also represent the differing management options appropriate for the care of different types of active and inactive lesions: NAC (No Active Care). PCA (Preventive Care Advised) and OCA (Operative Care Advised). There are considerable methodological difficulties in drawing valid comparisons between studies using incompatible criteria and simulations. However, it is apparent that no caries diagnostic tool in current clinical use fulfils all of the ideal criteria for measurements needed to plan and monitor appropriate care. Systems providing reliable serial measurements with which to assess future caries risk and present caries activity are urgently required as diagnostic tasks are becoming both more difficult and more important from the standpoint of long-term oral health. Existing diagnostic tools frequently rely on subjective judgements and provide only semi-quantitative measures insensitive to smaller lesions. In the future tools are needed which are objective, quantitative and which can provide acceptable compromises between sensitivity and specificity for a wide range of applications for individual patient care as well as for research and survey use. Key problem areas with existing tools include confusion in terminology and between caries assessments made by clinicians and epidemiologists as well as the lack of valid measurements relating to the activity of primary root caries and secondary caries. Deficiencies with current tools impact on the care of individuals by allowing false negative diagnoses of hidden occlusal dentine lesions and approximal cavities on the one hand, whilst generating some false positive diagnoses on sound surfaces leading to inappropriate decisions to restore on the other. At the population level, current conventional tools significantly underestimate overall caries experience. In future the adoption of more accurate and reliable methods would facilitate more effective preventive care and promote more appropriate restorative treatment decisions. Research in this area should focus for the next five years on diagnostic technologies which: 1) inform valid prospective caries risk assessments for different age groups, 2) can help to determine present caries activity and monitor lesion behaviour over time and 3) help identify methods which can implement existing and new research knowledge about diagnostic tools into clinical and research practice.