Papers by Author: Tomaz Kosmač

Abstract: A two-step, biomimetic approach was applied for the rapid deposition of octacalcium phosphate (OCP) coatings on zirconia ceramics (Y-TZP). In the first step, sintered zirconia discs were immersed into a supersaturated Ca-P solution with pH=7.4 (CPS1). In the second step, the substrates were transferred from the CPS1 to another Ca-P solution with a lower pH (CPS2). After 6 hours of immersion in the CPS2, a thick coating consisting of large OCP crystals was obtained. Afterwards, the coated substrates were subjected to a thermal treatment in order to improve the attachment of the coating to the substrate.

Abstract: The aim of this study was to functionalize the surface of Ce-TZP/Al₂O₃ dental ceramic with a nano-structured alumina coating to improve resin bonding. A total of 40 densely sintered disc-shaped specimens (15.5 + 0.03 mm in diameter and 2.6 + 0.03 mm thick) were produced from commercially available NANOZIR blocks and randomly divided into 2 groups of 20. Half of the discs in each group received an alumina coating that was fabricated by exploiting the hydrolysis of aluminum nitride (AlN) powder. The coating was characterized using scanning electron microscopy (SEM). The shear bond strength of the self-adhesive luting cement G-cem was then studied for the coated and uncoated surfaces before and after thermocycling (TC). The SEM analysis revealed that the application of an alumina coating to Ce-TZP/Al₂O₃ ceramics created a highly retentive surface for resin penetration. The resin bond strength to the coated groups was significantly higher than to the uncoated groups, both before and after TC (p ≤ 0,05).