Reliability and Properties of Ground Y-TZP-Zirconia Ceramics

TLDR

Yttria‑stabilized zirconia ceramics are a high‑performance, biocompatible material well suited for posterior fixed partial dentures. The study tests whether inner surface grinding of Y‑TZP crowns alters their strength and reliability, depending on grinding parameters. Flexural strength, surface roughness, and fracture toughness were measured on samples ground face‑ and peripheral‑wise at varying feed velocities and cutting depths, compared to lapped controls, and analyzed with ANOVA and Weibull statistics. Inner surface grinding markedly reduced the strength and reliability of Y‑TZP zirconia versus lapped controls, with surface compressive stress and grinding‑induced flaws counteracting each other, underscoring the need to optimize grinding for CAD/CAM all‑ceramic restorations.

Abstract

Yttria-stabilized zirconia ceramics is a high-performance material with excellent biocompatibility and mechanical properties, which suggest its suitability for posterior fixed partial dentures. The hypothesis under examination is that the strength and reliability of Y-TZP zirconia ceramics are affected by the inner surface grinding of crowns, and vary with the grinding parameter. Flexural strength, surface roughness, and fracture toughness were determined on samples machined by face and peripheral grinding with varied feed velocities and cutting depths. Results have been compared with those on lapped samples. Analysis of variance and Weibull parameter were used for statistical analysis. It was found that inner surface grinding significantly reduces the strength and reliability of Y-TZP zirconia compared with the lapped control sample. Co-analysis of flexural strength, Weibull parameter, and fracture toughness showed counteracting effects of surface compressive stress and grinding-introduced surface flaws. In conclusion, grinding of Y-TZP needs to be optimized to achieve the CAD/CAM manufacture of all-ceramic restorations with improved strength and reliability.