The effect of Er: YAG laser irradiation on bonding properties of IPS e.max CAD ceramics

Abstract

Objective To investigate different Er:YAG laser power settings on the bonding properties of IPS e.max CAD ceramics. Methods 96 IPS e.max CAD ceramics blocks (5 mm × 5 mm × 5 mm) were prepared and randomly di⁃ vided into 8 groups (n = 12), the untreated blocks served as the control, while one of the experimental groups was treat⁃ ed with 4.5% HF for 20 seconds, six remaining test group (C、D、E、F、G、H) were treated with different Er: YAG laser power settings: 100 mJ、200 mJ、300 mJ、400 mJ、500 mJ and 600 mJ. Morphology of the ceramic surface was observed by atomic force microscopy and its shear bond strength (SBS) was tested. Results Higher shear bond strength values were found in group C⁃H compared to group B, the highest is group F (24.12 ± 1.91) MPa. The difference was statistical⁃ ly significant. The atomic force microscope observation of the surface structure showed that the control group was smooth and flat, and the HF⁃like etching group formed a uniform needle⁃like convex structure. The laser group gradual⁃ ly formed a regularly arranged cylindrical convex structure, in which the surface of the G and H groups was damaged. Conclusion The Er: YAG laser power settings of 400 mJ can be used as an effective pretreatment method before bond⁃ ing of IPS e.max CAD ceramic.

Keywords

• Er: YAG laser
• IPS e.max CAD
• Bonding strength
• Atomic force microscope
• Microphology