The Effects of Current Production Techniques on The\rsurface Roughness, Oxide Layer Thickness And\rporcelain Bond Strength of Cobalt-Chromium And\rtitanium Substructures

Abstract

Aim: This study aimed to evaluate the oxide layer, surface roughness, and\rbond strength with porcelain of cobalt-chromium (Co-Cr) and titanium (Ti)\rsubstructures produced using casting, milling and selective laser sintering\rtechniques.\rMethodology: A total of 180 disc-shaped metal samples with a diameter\rof 1 cm and a thickness of 3 mm were produced. The samples were divided\rinto six groups (n=15) according to the technique used to produce the\rmetal substructures—casting, milling, and SLS—and the chemical\rcomposition of the metal substructure—Co-Cr and Ti. Then roughness\raverages (Ra) of the sample surfaced were calculated with a contact-type\rprofilometer. Nondestructive energy-dispersive X-ray was performed to\rensure that the layer displayed in contrast was the oxide layer, and the\raverage oxide layer thickness was calculated from scanning electron\rmicroscope images. Metal-porcelain complexes were subjected to shear\rbond strength test and failure types were noted. Two-way multivariate\ranalysis of variance (MANOVA) was used to compare oxide layer thickness,\rsurface roughness, and shear bond strength according to the metal and\rproduction technique, and Tukey’s honestly significant difference (HSD)\rtest was used for multiple comparisons of the main effects.\rResults: Two-way MANOVA revealed that the metal and technique used\rin the substructure production had significant effects on surface\rroughness, oxide layer thickness and shear bond strength (p < 0.001). Ti\rgroups exhibited thicker oxide layer formation than Co-Cr groups. Low\rsurface roughness values were observed in the milling groups. The highest\rshear bond strength value (53.8 MPa) was observed in the Co-Cr group\rproduced by casting, while the lowest value (32.2 MPa) was obtained in\rthe Ti group produced by casting.\rConclusion: It should be kept in mind that there is no ideal production\rtechnique and that the effects of the production technique differ\rdepending on the metal used.