A proposal for restorative treatment is based on the expected efficiency of the treatment. Efficiency is determined by measuring the investment, such as the monetary and biological cost, against what is gained, such as functional restoration and durability. If one’s goal is to save tooth tissue in the restorative process, it is interesting to compare the conventional fixed partial denture with the adhesive fixed partial denture. The mean survival rate of conventional fixed partial dentures clearly exceeds the mean survival rate of adhesive fixed partial dentures but there are biological risks. Loss of vitality of the abutment teeth and the occurrence of caries are more prominent with conventional fixed partial dentures than with adhesive fixed partial dentures. Consequently, the possibility of replacing a conventional fixed partial denture with a new conventional fixed partial denture is limited. Because this and other clinical aspects cannot easily be expressed numerically, the patient should be informed qualitatively about the advantages, disadvantages and uncertainties of the various types of fixed partial dentures.