The influence of Y-TZP surface treatment on topography and ceramic/resin cement interfacial fracture toughness

- C(T) shows be a reliable indicator of the zirconia/cement bond quality.
- Ra, Rsk and area variation were evaluated by AFM.
- Weibull analysis evaluates the structural integrity of the adhesion zone.
- SIE resulted in higher KIC values with great Weibull survivor probability.
- Remained alumina debris negatively affected the interface fracture toughness.

ObjectiveConsider the efficacy of glass infiltration etching (SIE) treatment as a procedure to modify the zirconia surface resulting in higher interfacial fracture toughness.MethodsY-TZP was subjected to 5 different surface treatments conditions consisting of no treatment (G1), SIE followed by hydrofluoric acid treatment (G2), heat treated at 750 °C (G3), hydrofluoric acid treated (G4) and airborne-particle abrasion with alumina particles (G5). The effect of surface treatment on roughness was evaluated by Atomic Force Microscopy providing three different parameters: Ra, Rsk and surface area variation. The ceramic/resin cement interface was analyzed by Fracture Mechanics KI test with failure mode determined by fractographic analysis. Weibull's analysis was also performed to evaluate the structural integrity of the adhesion zone.ResultsG2 and G4 specimens showed very similar, and high Ra values but different surface area variation (33% for G2 and 13% for G4) and they presented the highest fracture toughness (KIC). Weibull's analysis showed G2 (SIE) tendency to exhibit higher KIC values than the other groups but with more data scatter and a higher early failure probability than G4 specimens.SignificanceSelective glass infiltration etching surface treatment was effective in modifying the zirconia surface roughness, increasing the bonding area and hence the mechanical imbrications at the zirconia/resin cement interface resulting in higher fracture toughness (KIC) values with higher KIC values obtained when failure probability above 20% was expected (Weibull's distribution) among all the experimental groups.

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