Cariology has advanced over the past 30 years with scientifc advances in the knowledge of the caries process in term of its pathogenesis, its transmission, the demineralisation and remineralisation continuum, the mode of action of uoride, but also with respect to the great technological developments in biomaterials, equipment for the detection of caries lesions and methods for cavity preparation.This new scientifc knowledge combined with developments both technological and technique related, impose that both medically and ethically, the sole pertinent therapeutic model that is relevant is one that is based on prevention and treatment using the least invasive of approaches. This 'rational'model of care is known as minimal intervention dentistry.