The lack of scientific basis for the treatment of mutilated dentition and the lack of a correlation between the loss of molar teeth and oral function were the reasons for carrying out a doctoral research project into mutilated dentitions. According to the thesis, loss of teeth was increased with age and loss of teeth followed a similar pattern in all socio-economic classes. No correlation was found between the number of teeth lost and oral function. Only a weak correlation could be demonstrated between the number of occluding pairs of maxillary and mandibular teeth and subjective chewing ability. Subsequent clinical trials and questionnaire studies revealed that, basically, hardly any convincing reason is available for prosthetic replacement of posterior teeth, providing the presence of 3 occluding pairs of maxillary and mandibular teeth. On the strength of scientific evidence available, one may assume that a sound dentition containing at least 20 teeth, maxillary and mandibular frontal teeth and premolars, is satisfactory functionally and aesthetically. For these cases, any reason for prosthetic replacement is absent.