Effect of Sintering Temperature on Polymer Infiltrated Ceramic Network Materials

Objectives: To assess the surface characteristics and nanomechanics between several CAD/CAM resin composite blocks and polymer infiltrated ceramic network (PICN) materials.
Methods: Three CAD/CAM resin composites; Lava Ultimate (LU), Cerasmart (CS) and Grandio Bloc (GB), one commercial PICN block ;Vita Enamic (VE) and four model PICN materials sintered at different temperatures (Exp.125, Exp.130, Exp 135 and Exp 155) were tested. Forty samples were prepared with the dimensions of 14×12×2 mm for resin ceramic and VE blocks and 15x2 mm for model PICN materials. All samples were scanned using Peakforce Quantitative Nanomechanical (PFQNM) tapping mode atomic force microscopy (AFM) at multiple locations and two different scan sizes (20x20µm and 3x3µm). Surface gloss at 60° was determined for all groups. Data were analysed using one-way ANOVA, and Tukey’s post hoc test (α=0.05).


Results: Resin composite blocks showed smoother surfaces compared to PICN materials. Surface roughness values (Ra) ranged between 7.75 nm to 31.21 nm and gloss between 56.43 GU and 91.81 GU. Variation was noticed in terms of nanomechanical mapping within and between the groups. E-moduli ranged between 8.4 to 84.3 GPa. Images generated from the elastic modulus map values clearly indicated that all PICN materials had more than one phase and very different components.
Conclusions: CAD/CAM resin composite blocks exhibited higher gloss and lower roughness values compared to PICN materials. However, both commercial and model PICN materials showed higher stiffness than resin composite with the presence of at least two different phases. Sintering temperature appears to have a significant effect on material topography and nanomechanical properties. Model PICN sintered at 1550 °C showed comparable range of E modulus values to those of enamel.