Minimal intervention dentistry is now accepted as the contemporary approach for caries management. The development of adjunctive technologies to assist early lesion detection has led to widespread marketing of various devices over the past two decades. A thorough understanding of the clinical relevance and limitations of such devices is required to make valid interpretation of their results. This paper will discuss the most common commercially available carious lesion detection technologies in order to give dental practitioners clear information about the devices' scientific principles, advantages and limitations within a clinical context.