Silicon nitride bioceramics in healthcare

Abstract

Silicon nitride (Si 3 N 4 ) is biocompatible and stable in vivo, and these properties, when combined with its superior mechanical properties, make Si 3 N 4 an attractive ceramic implant material in some healthcare applications, particularly in orthopedic surgery. Si 3 N 4 is used in spinal fusion surgery, is under development for use as bearings in joint replacement, and is being considered for use as dental implants. While Si 3 N 4 implants are currently created using conventional ceramic processing techniques, additive manufacturing provides the capacity to create custom implants with the required anatomical shape, precise dimensions, and well-controlled microstructure. Si 3 N 4 can be created with a smooth or microrough surface topography, and its surface chemistry can be varied from a silica-rich to a predominantly silicon-amine composition, which can influence the response of cells, tissues, and bacteria in vivo. Si 3 N 4 implants have shown attractive osseointegration and antimicrobial activity in vivo, while Si 3 N 4 bearings have shown low wear rates when articulating against itself or against polyethylene. The objective of this article is to review recent developments in the design, processing, and evaluation of Si 3 N 4 implants for healthcare applications. K E Y W O R D S antimicrobial activity, in vivo evaluation, silicon nitride bioceramics, spinal fusion, surface modification, total joint replacement

A review of recent advances in tribology

“…Biomaterials research for artificial joint replacements mainly focused on the improvement of the wear resistance currently used in clinical practice, such as metallic (cobalt chromium molybdenum alloys and titanium alloys), polymeric (ultra-high molecular weight polyethylene, UHMWPE) and ceramics, as well as novel biomimetic materials and combinations with potentials for longer lasting life of the implant. Silicon nitride bioceramics were investigated [317] as well as composite ceramics, to optimize both the hardness and the toughness, such as zirconia toughened alumina [318], carbonfiber reinforced silicone-carbide [319], and hexagonal boron nitride mixed with silicon nitride [320], etc. In addition to the improvement of highly crossed linked UHMWPE, potentially high performance polymers and composites were also investigated, such as ultra-low-wear polyethylene [321], polyetheretherketone (PEEK) [322] and hydrogels [323], porous polycarbonate-urethane and UHMWPE blends [324], polycarbonate urethanes [325], and polyvinyl alcohol and polyvinyl pyrrolidone blend hydrogels [326].…”

Development of silicon nitride ceramic for CAD/CAM restoration

“…Silicon nitride (Si 3N4) ceramic is more reliable than zirconia in term of its structure and thus it is a preferred candidate for many applications in industrial engineering and orthopedic implants [8][9][10][11] . As an alternative to zirconia, Si3N4 ceramic has a potential because of its high fracture toughness and strength, wear resistance, antimicrobial and non-cytotoxicity [9][10][11][12][13][14][15] . Therefore Si3N4 ceramic is a suitable material that can be used to produce a core structure for dental crowns or bridges.…”

Towards Functional Silicon Nitride Coatings for Joint Replacements

“…In this work, we investigate silicon nitride (SiN x ) coatings for joint implants. This type of coating has previously shown promising properties in terms of high biocompatibility, hardness, and low wear rates [17][18][19][20]. A further possible advantage of this coating compared to other ceramic coatings is its slow solubility in aqueous solutions [21,22], in combination with the high biocompatibility of its wear particles and ions [23].…”