Effect of Different Modification Techniques on Mechanical and Physical Properties of E-Max CAD Substrate

Abstract

The world's best-selling glass-ceramic is IPS E.Max CAD. It is known for its versatile applications and is appropriate for the effective manufacturing of comprehensive dental restorations. This experimental study aimed to evaluate the morphological changes, surface roughness, and micro-hardness after modification techniques with KHF2 and NH4HF2 acid etching on e-max cad substrate. Materials and Methods: Forty disc shape of E.Max CAD specimens (thickness 3mm and diameter 10mm) were fabricated and divided into four groups according modification techniques (control group, sandblasting by 70µm of Al2O3, etching with 70 mg of KHF2 and etching with 70mg of NH4HF2),10 samples for each group. Surface roughness, micro-hardness, and microstructure changes of e-max CAD substrate have been measured. Results: The higher mean value for the surface roughness (Ra) was in the group (ECNH4HF2), followed by (ECKHF2) whereas the lowest mean value of surface roughness was in the group (ECC) followed by (ECSB). While for the micro-hardness test, the (ECKHF2) group demonstrated the highest mean value in comparison with other treated groups. Finally, SEM results for both untreated and sandblasted groups revealed there is a smooth and no deep morphological change for their surfaces. While the SEM analysis revealed that the e-max cad surfaces after KHF2 and NH4HF2 showed rough morphology with fine grains result and random porosities. Conclusions: Etching with KHF2 and NH4HF2 yielded higher microstructure changes and roughness than other techniques. While KHF2 etchant was more effective on E.Max CAD surface micro-hardness in comparison with other treated groups.