Milled prosthesis materials milled by a vhf s1 milling machine exhibited better surface properties than comparable test objects from a 3-D printer or conventional production, according to researchers at the University Hospital of Tubingen, Charite University Medicine Berlin, and the First State University of Setchenow in Moscow.
The study examined subtractive and additive samples for mechanical polishability. Prosthesis materials obtain a smoother surface after polishing, which is particularly relevant in plaque accumulation, the researchers said. Also, common prosthetic aids must meet certain qualitative criteria for successful rehabilitation of edentulous patients, including a surface that is as smooth as possible, the researchers added.
Abrasive wear during chewing or mechanical cleaning, poor dental hygiene, and reduced salivation can lead to increased plaque accumulation and diseases, the researchers said, which is why mechanical or chemical polishing as well as coating processes are applied to reduce the microbial adhesion of the denture surface.
The study produced and examined three groups of materials: conventionally produced denture bases, which are manufactured by cold polymerization of PMME; denture samples milled with a vhf S1 milling machine; and test objects from a 3-D printer. Ten samples from each group were left untreated. Another 10 objects were pre-polished, and 10 final samples were polished to a high gloss. The surface values of the samples then were compared among other criteria.
For the fabrication of the milled prosthesis sample, one specimen was designed virtually in CAD software. The stereolithography (STL) file was then exported to the vhf software DentalCAM. Next, the file was positioned inside a circular blank made of pre-polymerized PMMA and wet milled with the vhf S1.
In all three categories, the researchers said, the milled samples showed clearly better surface characteristics than the 3-D printed and conventionally produced ones. Also, the highly polished samples showed the statistically best surface values.
The study, “Surface Characteristics of Milled and 3D Printed Denture Base Materials Following Polishing and Coating: An In-Vitro Study,” was published in Materials.
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