Surface roughness and volumetric contraction of a Y-TZP ceramic sintered by microwave energy and by resistive heating

Nayara Fernanda Barchetta, Larissa Guazzelli Nanni, Jean Soares Miranda, Dolores Ribeiro Ricci Lazar, Valter Assui, Guilherme de Siqueira Ferreira Anzalone Saavedra

Abstract


Objective: The aim of this study was to evaluate a Y-TZP ceramic sintered by a microwave protocol on volume shrinkage and surface roughness. Material and Methods: Twenty four (N=24) Y-TZP discs were fabricated by milling in CAD/CAM for size standardization. The mean final dimensions of the specimens were 15 mm X 1.6 mm. Samples were divided into 2 groups (n=12): conventional resistive heating sintering protocol (C - Control) and microwave sintering protocol (MO - experimental). For the characterization of the specimens, surface roughness (Ra and Rz parameters) was evaluated with a roughness tester, and volume shrinkage was measured with a hand micrometer. Data were statistically evaluated by Student’s t and Mann-Whitney U tests (α=0.05). Results: The roughness results were: 0.25 μm ± 0.02 (Ra) and 2.68 μm ± 0.666 (Rz) for the MO samples; 0.26 μm ± 0.04 (Ra) and 2.73 μm ± 0.461 (Rz) for the C group (Ra: p = 0.19; Rz: p = 0.81). The shrinkage results was: MO (21.02% ± 2.70) and C (20.10% ± 0.52) (p = 0.274). Conclusion: The conventional and microwave sintering methods were similar regarding surface roughness and volume shrinkage of Y-TZP dental ceramic.

Keywords

Bioceramics; Microwave sintering; Roughness surface; Zirconia.


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DOI: http://dx.doi.org/10.14295/bds.2017.v20i4.1481