Objectives: An important criteria for the success of a crown is its fit. However, in the patient's mouth fit can only be evaluated without exact measurements. This study describes the correlation between marginal fit of crowns and their subjective evaluation by dentists and dental technicians. Methods: 25 extracted human teeth were randomly divided in 5 groups and prepared with a circular shoulder. For each of the 5 groups cast crowns were made from different metals (AuAgCu, AuPdPt, PdAgAu, CoCrMo, Ti). The metals were processed according to the manufacturers instructions using the appropriate investment material and casting devices. The crowns were fitted onto the prepared teeth and cemented with provisional cement. 20 experienced professionals (10 dentists and 10 technicians) were asked to evaluate the fit of the crowns with an unused standardised dental probe. The examiners were unaware of the alloys. After collecting the data with a questionnaire the crowns were removed and cemented with ZnO-Phosphate cement under standardised conditions. The excess of the cement was removed with a probe and the marginal gap (cement width) was circularly investigated using a light microscope. Means of the gaps were calculated for each alloy and statistically compared using H-test and U-tests. Correlations between objective measurements and subjective evaluation were calculated by Spearman-tests. Results: The different alloys showed significantly different marginal fits ranging from 35 µm to 92 µm (mean). There was no strong correlation between the subjective findings and objective data. Conclusions: It is suggested that clinicians use other criteria than marginal gaps to evaluate fit of crowns (e.g. over- or under contouring of crowns).

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