It can be expected that the percentage of edentulous people wil decrease in the coming decades as a result of an improved oral health, whereas the number of edentulous people will increase as a result of the strong increase of the ageing population. If the preservation of the natural dentition is no longer possible, the remaining teeth of a mutilated dentition have to be extracted according to some specific principles. But also the aftercare of the edentulous patient has to be extended according to some specific guidelines, within the framework of the so-called 'preventive-prosthetic-treatment-strategy'. Preservation of the alveolar process is the main goal in both cases.