A comparison of the radiopacities of CAD-CAM restoratives: Effect of thickness.

Purpose: To evaluate the radiopacities of CAD-CAM materials using digital techniques.

Methods: Five different CAD-CAM materials were used (Cerasmart, LAVA Ultimate, Cerec Blocs C, Tetric CAD, and IPS e.max CAD) in this study (n= 5). For each group, samples with thicknesses of 1 and 2 mm were prepared. As a control, tooth slices with 1 and 2 mm thicknesses and a 99.5% pure aluminum step wedge were used. The samples, tooth slices, and step wedges were placed on a photostimulable phosphor plate. Radiographs were taken at 30 cm distance with 7 mA, 70 kVp, and 0.32 ms exposure time. The images were analyzed using the ImageJ software to measure the mean gray values. Data were analyzed with Kruskal-Wallis H test and the Mann-Whitney U test (P< 0.05).

Results: In the comparison of CAD-CAM materials with 1 and 2-mm thicknesses, the highest radiopacity value was seen in LAVA Ultimate samples (2.67 ± 0.05 for 1 mm samples: 5.74 ± 0.13 for 2 mm samples). The lowest value in 1 mm samples was seen in IPS e.max (0.59 ± 0.07), and in 2 mm samples, in Cerec Blocs C samples (1.49 ± 0.11). The results showed that the radiopacity values of the samples were associated with increased thicknesses. The 2 mm samples' radiopacity values were statistically significantly higher compared with the 1 mm samples. All samples except IPS e.max CAD and Cerec Blocs C had higher radiopacity than dentin (P< 0.05).

Clinical significance: The radiopacity values were affected by thickness and type of materials. Comprehensive knowledge about the radiopacity of materials enables the selection of appropriate materials to achieve clinical success, which serves as a useful diagnostic aid in determining the long-term durability of restorations.