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The effect of surface treatments on the microroughness of laser‐sintered and vacuum‐cast base metal alloys for dental prosthetic frameworks
Author(s) -
CastilloOyagüe Raquel,
Osorio Raquel,
Osorio Estrella,
Sánchezaguilera Fátima,
Toledano Manuel
Publication year - 2012
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.22050
Subject(s) - materials science , surface roughness , profilometer , alloy , metallurgy , metal , ceramic , surface finish , laser , base metal , coating , composite material , optics , physics , welding
This study aimed to evaluate the effect of four chemomechanical surface treatments on the surface average microroughness and profile of laser‐sintered and vacuum‐cast dental prosthetic structures. Square‐shaped blocks (10 mm × 10 mm × 1.5 mm) were prepared as follows: (1) laser‐sintered CoCr (L) (ST2724G); (2) cast CoCr (C) (Gemium‐cn); and (3) cast NiCrTi (T) (Tilite). Specimens of each alloy group were randomly divided into five subgroups ( n = 10 each), depending on the conditioning method used: (1) no treatment (control); (2) sandblasting (125 μm Al 2 O 3 ‐particles); (3) silica coating (50 μm silica‐modified Al 2 O 3 ‐particles); (4) oxidation; and (5) oxidation plus opacification. Subgroups 2 and 3 represent “inner” pretreatments proposed for ceramometal restorations to improve the metal surface area available for luting cements. Subgroups 4 and 5 are the “outer” pretreatments required for bonding the aesthetic veneering ceramics to the underlying metal frameworks. Average surface roughness (Ra/μm) was determined using a surface profilometer. Data were analyzed by two‐way ANOVA and Student–Newman–Keuls tests (α = 0.05). Metal surface topography was SEM‐analyzed. Despite the inner pretreatment applied, L samples resulted in the highest microroughness ( P < 0.001), whereas sandblasting produced a surface‐smoothing effect in cast specimens. After oxidation, a significant increase in surface roughness occurred in all groups compared with controls, L specimens being the roughest ( P < 0.001). Opacification caused a flattening effect of all oxidized structures; all opacified groups resulting in similar microroughness. Laser sintering of CoCr enhances the roughness of metal structures, which may improve the frameworks' microretention of the cements, and of the opaquer before the copings are veneered with the aesthetic ceramics. Microsc. Res. Tech. 75:1206–1212, 2012. © 2012 Wiley Periodicals, Inc.