Improving the resistance to sliding contact damage of zirconia using elastic gradients

Abstract

Zirconia-based ceramics with high strength have been identified as a material of choice for sliding components in a variety of biomedical and engineering applications. Despite the high flexural strength, zirconia prostheses are still vulnerable to wear and surface damage. We hypothesize that such tribological damage may be substantially mitigated by an engineered grading of elastic modulus at the ceramic surface. In this study, graded structures were fabricated by infiltrating glass into the top and bottom surfaces of zirconia plates, with resulting diminished modulus in the outer surfaces. The plates were then subjected to frictional sliding tests using a hard spherical indenter. Compared to non-infiltrated controls, infiltrated specimens showed a significant increase in the fracture loads, by over a factor of 3. The increase in the sliding contact resistance is attributed to the diminishing tensile stresses at the graded lower-modulus surface. The results confirm that suitably graded structures can be highly beneficial in the design of next-generation orthopedic and dental prostheses.

Performance of Dental Ceramics: Challenges for Improvements

“…This can be achieved through graded structures, gradually changing the material composition across the core veneer interface and the core intaglio surface. In one set of studies (Zhang and Kim, 2009;Zhang and Ma, 2009;Kim et al, 2010b), zirconia was infiltrated with a silicate glass with a matched coefficient of thermal expansion. The percentage of glass changed from 100% to none across a 120-µm interphase.…”

Exploring the optimal pre-sintering temperature on compressive strength and anti-fatigue property of graded zirconia-based glass/zirconia structure

“…The bio-inspired design concept has been recently introduced to the development of new all-ceramic materials. The synthetic functionally graded material (FGM) architectures have been proved to significantly reduce stress concentration at the interface and toughen all-ceramic restorations [2][3][4][5][6][7] . The synthetic procedure involves pre-sintering zirconia core and glass infiltration.…”

Optimizing the design of bio-inspired functionally graded material (FGM) layer in all-ceramic dental restorations

“…Within this functionally graded layer, stress concentration is significantly reduced by virtue of the gradually changing elastic modulus [6][7][8][9] . Inspired by DEJ, some researchers introduced the concept of a bio-inspired, functionally graded material layer structure between the ceramic core and cement to reduce stress [10][11][12][13][14][15] . Huang et al 10) developed a two-dimensional all-ceramic restoration model with a bio-inspired functionally graded material (FGM) layer between the ceramic core and cement.…”

“…By using a rate-dependent slow crack growth (RDEASCG) model, critical loads were significantly improved and subsurface stresses that might induce cracks in the ceramic layer were reduced 11) . Numerous studies have also shown that functionally graded structure fabricated by infiltrating glass into the ceramic core exhibited higher load-bearing capacity through finite element analyses and contact loading experiments [12][13][14][15] . However, few studies focused on the explicit optimal design of bio-inspired functionally graded material layer (variation of gradients in elastic modulus in FGM), which might minimize tensile stress between the ceramic core and cement and uniformly distribute stress in FGM.…”

“…Recently, the bio-inspired design concept was introduced to the research field of all-ceramic restorations. Previous studies had shown that synthetic DEJ-like joints with functionally graded material (FGM) architectures could significantly reduce stress concentration at the interface and toughen all-ceramic restorations [10][11][12][13][14][15] . However, the explicit optimal design of functionally graded material layer (variation of gradients in elastic modulus in FGM) between the ceramic core and cement remained to be proposed.…”