The advances of pulp biology combined with detailed description of the carious lesion environment, as well as the clinical evidence of treating deep lesions, have modified the view of pulp inflammation as being the nonstopping train toward apoptosis and pulp necrosis. The dentine comprises bioactive extracellular matrix, and during carious demineralization of the dentine, there is a release of bioactive molecules which can trigger the odontoblasts being members of the first line of host defense. An update of caries pathology from reversible pulpitis to necrosis is presented. A well-defined radiographical subdivision of the profound carious lesion into deep and extreme deep may be beneficially for an improved understanding of the point of irreversibility of pulp inflammation. However, the clinical estimation of inflammation remains a challenge.