27 June 2022

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Nanoceramics, PICN and lithium disilicate for CAD/CAM system: mechanical properties and internal fit.

Simona Chirico

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Computer-aided design/computer-aided manufacturing (CAD/CAM) was introduced in dentistry forty-years ago, and gained popularity worldwide because of advancements in restorative materials with characteristics such as crack tolerance, ease of clinical use and good performance. Among the most common CAD/CAM materials we found: nanoceramics, vitreous ceramics interpenetrated in a resin matrix (PICN) and lithium disilicate. These materials belong to different families of ceramics and therefore have different properties. 

But which material among these guarantees a better result?

The study published by Goujat et al, in the Journal of Prosthetic Dentistry, tried to give an answer by analyzing the mechanical properties and internal fit of these CAD / CAM materials.      

MATERIALS AND METHODS
The materials tested in this study were a PICN material (Vita Enamic), 2 composite resin nanoceramics (Lava Ultimate; 3M ESPE and Cerasmart; GCDental Products), and a lithium disilicate glass-ceramic (IPS e.max CAD). Mechanical properties were evaluated according to ISO norm DIS 6872:2013. Bar-shaped specimens (18×3×3 mm) were prepared and submitted to a 3-point bend test using a universal testing machine at a cross-head speed of 0.5 mm/min. In addition, identical cavities were prepared in 60 human mandibular extracted molars (n=15) and optically scanned to receive mesioocclusodistal inlays milled with the 4 materials tested in a CEREC Inlab milling machine. The replica technique and a stereomicroscope (×20) were used to measure the internal fit of the inlays at 9 preselected locations. All data were statistically analyzed using 1-way ANOVA and the post hoc Tukey multiple comparison or Games-Howell test (a=.05).

RESULTS
As can be seen from the table below (table 1), the best results were recorded by lithium disilicate.

CONCLUSIONS
Despite all these CAD / CAM materials are valid for a restoration, the best results were recorded for the lithium disilicate IPS e.max CAD followed by the Cerasmart nanoceramic

For additional informations: Mechanical properties and internal fit of 4 CAD-CAM block materials