ORIGINAL ARTICLE   

Minerva Stomatologica 2018 December;67(6):237-45

DOI: 10.23736/S0026-4970.18.04138-9

Copyright © 2018 EDIZIONI MINERVA MEDICA

lingua: Inglese

Y-TZP surface behavior under two different milling systems and three different accelerated aging protocols

Amanda M. dal PIVA ¹ ✉, João Paulo TRIBST ¹, Laísa D. GONDIM ², Isabella L. RIBEIRO ³, Fernanda CAMPOS ⁴, Anelyse ARATA ⁵, Rodrigo O. SOUZA ⁶

¹ Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (UNESP), São José dos Campos, Brazil; ² Federal University of Paraíba (UFPB), João Pessoa, Brazil; ³ Department of Social Odontology, Federal University of Paraíba (UFPB), João Pessoa, Brazil; ⁴ Department of Dentistry, Paraíba State University (UEPB), Araruna, Brazil; ⁵ Nuclear and Energy Research Institute, National Nuclear Energy Commission (IPEN-CNEN/SP), São Paulo, Brazil; ⁶ Division of Prosthodontics, Department of Restorative Dentistry, Federal University of Federal University of Rio Grande do Norte (UFRN), Natal, Brazil

BACKGROUND: To evaluate the influence of aging and milling system on zirconia surface roughness (SR) and phase transformation.
METHODS: Eighty crowns were divided in two groups according to yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic milling system (CAD-Neodent or MAD-Zirkonzahn). The crowns were submitted to different aging protocols (N.=10): 1) no aging; 2) autoclaving; 3) pH cycling; or 4) thermocycling. Next, the samples were submitted to an optical profilometry analysis to determine differences in the SR (µm). An X-ray diffraction analysis (XRD) was performed to quantify the percentage of monoclinic phase transformation. SR data was analyzed by two-way ANOVA (α=0.5%).
RESULTS: Aging protocol (P=0.42) and milling system (P=0.08) had no influence on the SR. However, the number of monoclinic phases was influenced by the autoclaving and pH cycling.
CONCLUSIONS: The surface roughness of zirconia-based crowns was not influenced by low temperature degradation or milling system. Regarding the phase transformation, autoclaving and pH-cycling aging presented a monoclinic phase increase when compared to the control group and thermocycled groups.

KEY WORDS: Yttria-stabilized tetragonal zirconia - Surface properties - Prosthodontics - Dental materials