engleski

Surface topography of unglazed, glazed and polished feldspathic ceramics using Atomic Force Microscopy

Dental ceramics are attractive dental materials as a result of their superior aesthetics and biocompatibility. However, they are brittle and inclined to premature failure, especially if subjected to repeated contact strain and moist environment. Surface structure of dental ceramics is important because it directly affects mechanical properties and aesthetic value of restorations. The aim of this study was to investigate the surface topography of glazed, unglazed, and unglazed polished feldspathic ceramics. Metal-ceramic plates (9.0 × 9.0 × 1.2 mm) composed of Ni-Cr alloy (Wiron 99, Bego Germany) and glazed or unglazed feldspathic ceramics (IPS Classic, Ivoclar-Vivadent, Schaan, Liechtenstein) were prepared according to the manufacturer's instructions. The surface of one unglazed specimen was polished with medium and fine diamond (Komet Gebr. Brasseler GmbH and Co KG Lemgo-D) for 20 seconds and afterwards with rubber cup EXA Cerapol 0301G Edenta AG Dentalprodukte Switzerland) for 20 seconds. The surface topography of the samples was examined by atomic force microscopy (AFM). The glazed specimen had the lowest surface roughness (scan area 100μ m x 100μ m, Ra=61 nm) and the unglazed a slightly higher (scan area 100μ m x 100μ m, Ra=70.9 nm). An increase in surface roughness was found in the unglazed polished specimen (scan area 100μ m x 100μ m Ra=147 nm). The results show that polishing of dental feldspathic ceramics should not be a replacement for glazing. In order to achieve a satisfactory surface smoothness glazing is the procedure of choice.

dental ceramic; Atomic Force Microscopy; surface topography; polishing

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