Effect of pH and Fluoride on Behavior of Dental ZrO2 Ceramics in Artificial Saliva

Author(s)

Mukaeda, L. E. ; Robin, A. ; Santos, C. ; Taguchi, S. P. ; Machado, J. P. B. ; Borges, L. A., Jr. ; Salgado, L ; Ambrozio, F

• Document type: Journal article
• Source: Materials Science Forum; v. 660-661, p. 6-pg., 2010-01-01.

Abstract

A considerable increase in the ceramic products demand occurred due to the evolution of dental restoration techniques and these materials must resist to the complex mouth environment. The pH of saliva can decrease significantly due to the ingestion of acidic foods and beverages and mainly due to reactions occurring during bacteria metabolism that lead to the formation of organic acids. Fluorides are also present in the mouth since fluorides are usually added in drinking water, mouth washes, tooth pastes and gels for the prevention of plaque and caries formation. The combination of low pH and presence of fluorides can lead to the formation of HF and HF2- which are detrimental to metallic and probably to ceramic devices. In this work, commercial blocks of ZrO2 ceramics (ProtMat Materiais Avancados(R) and Ivoclar(R)) were immersed in Fusayama artificial saliva of different pHs and fluoride concentrations. The properties of the as-produced ceramics (crystalline phases (XRD), microstructure (SEM), roughness (3D surface topography AFM) and mechanical resistance Vickers hardness (Hv) and fracture toughness (K-IC) were evaluated. Some of these properties were also determined after the immersion tests as well as the mass variation of the samples in order to evaluate the resistance of these ZrO2 ceramics to degradation under these conditions. (AU)