The difference between carious lesion diagnosis and carious lesion detection is discussed here. Concerning carious lesions, 3 diagnostic requirements should be fulfilled: to detect lesions, to assess surface integrity, and to assess lesion activity to support clinical decision making. The first and most important diagnostic method is meticulous visual-tactile inspection. This is the only method that potentially contributes to all 3 diagnostic requirements. All other methods that are presented in this chapter, i.e., bitewing radiography, fluorescence-based technologies, and transillumination methods, are limited to assessing lesion depth in surfaces that are not visible to the eye and thus contribute to lesion detection only. At the end of the chapter, recent developments in objective lesion activity assessment are presented.
