The application of different preventive measures has resulted in a decline of clinically detectable carious lesions in children and adolescents. Not only have caries symptoms changed significantly, but the number of extracted teeth in adults has decreased. Due to these epidemiological facts, modern conservative dentistry is based on a careful risk analysis and caries diagnosis, which also takes into consideration biological and psychosocial components of caries etiology. Conservative dentistry will fail if the dentists are only interested in repairing defects. Simultaneous with the positive outcome of prevention, some unanswered problems have arisen, for which there are no adequate solutions. In young children, caries prevalence is still high and the restorative care of these primary teeth should be improved. For adolescents, early detection of carious lesions should be improved and polarization of caries prevalence should be eliminated. In older adults, evidence-based therapy options for treatment of erosions, abrasions, and root caries are lacking. For seniors needing general care, preventive and restorative concepts should be established.