Evaluation of Two Protocols to Measure the Accuracy of Fixed Dental Prostheses: An In Vitro Study

Purpose The aim of this in vitro study was to compare two measurement protocols of the internal and marginal fit of three‐unit zirconia fixed dental prostheses (FDPs). Materials and Methods Forty‐four FDPs were fabricated for standardized dies by two laboratory CAD/CAM systems: Cercon (n = 22) and Ceramill (n = 22). The fitting was tested using a replica technique (RT = technique 1) with a light‐body silicone stabilized with heavy‐body material. After producing the replicas, cross‐sections were made in the buccolingual and mesiodistal directions. FDPs were cemented on definitive dies, embedded, and sectioned (CST = technique 2). The marginal and internal fits were measured under an optical microscope at 50x magnification with a special software program. Data evaluation was performed according to prior studies at a level of significance of 5%. Results The mean internal gap width was 51 ± 36 μm for the RT and 52 ± 35 μm for the cross‐section technique (CST) (p = 0.74). The mean marginal gap width was 27 ± 18 μm for RT and 30 ± 19 μm for CST (p = 0.19). Statistical tests showed no significant differences (p > 0.05). Conclusions Both techniques can be used for fit evaluation; however, the noninvasive RT is suitable for clinical use.