Bending properties of additively manufactured commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs: Effect of surface treatment

Abstract

BackgroundAdditive manufacturing of metallic materials, a layer-wise manufacturing method, is currently gaining attention in the biomedical industry because of its capability to fabricate complex geometries including customized parts tting to patient requirements. However, one of the major challenges hindering the full implementation of additively manufactured parts in safety-critical applications is their poor mechanical performance under cyclic loading. This study investigated both quasi-static bending properties (bending stiffness, bending structural stiffness, and bending strength) and bending fatigue properties of additively manufactured (AM) commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs. The results were compared with commercially manufactured (CM) counterparts. MethodsAM CPTi LC-DCP with different surface conditions including as-built, single shot-peened, dual shotpeened, and chemically assisted surface enhancement conditions and CM counterparts were mechanically tested based on ASTM International standard for metallic bone plates (ASTM F382). Bending stiffness, bending structural stiffness, and bending strength was measured by quasi-static bending tests, and bending fatigue properties were obtained by cyclic bending tests. ResultsBending stiffness and bending structural stiffness of AM CPTi LC-DCPs are comparable to CM counterparts; however, the bending strength of AM CPTi LC-DCPs is lower than CM counterparts. The fatigue strength of as-built AM CPTi LC-DCPs is lower compared to the CM counterparts. However, after post surface treatments, single shot-peened, dual shot-peened, and chemically assisted surface enhancement AM CPTi LC-DCPs exhibit statistically comparable fatigue strength to the CM CPTi LC-DCPs. ConclusionAM CPTi LC-DCP could be considered as an alternative to CM LC-DCP in applications that require less bending strength (~5.44 N•m). Post surface treatment should be considered on as-built implants to improve fatigue strength.

The Effects of Submerged Laser Peening, Cavitation Peening, and Shot Peening on the Improvement of the Torsional Fatigue Strength of Powder Bed Fused Ti6al4v Produced Through Laser Sintering

“…Thus, it is necessary to remove surface defects and/or reduce surface roughness using other methods such as machining [25]. It has been reported that the fatigue life of PBF/ Ti6Al4V decreases with an increase in the maximum surface roughness [26], and the surface roughness affects the fatigue strength of PBF/ Ti6Al4V [27][28][29][30][31], thus a reduction in the surface roughness of PBF/ Ti6Al4V is required to improve the fatigue properties. To reduce surface roughness of PBF metals, mechanical surface finishing [32], ultrasonic cavitation abrasive finishing [33], chemical etching [34], ultrasonic shot peening [35], cavitation abrasive surface finishing [36,37], hydrodynamic cavitation abrasive finishing [38,39], barreling [40], and linishing [40] have been proposed, and the improvement of fatigue strength of PBF/Ti6Al4V was demonstrated [32,36,37,40].…”

Gentamicin Eluting 3D-Printed Implants for Preventing Post-Surgical Infections in Bone Fractures

“…Surgical stabilization using metal implants or plates is regular in medical practice, especially for fracture fixation, and such implants are convenient to personalize utilizing AM. 13,47 Such implants could be custom modified not just based on the nature of the injury but also could facilitate alterations in surface roughness, topography, and drug loading. 15,48 The customized implants also provide flexibility with site specificity of multifunctional coatings, 17 improve osseointegration, 3 and antibacterial deposition.…”

“…Laser powder bed fusion (L-PBF) techniques can be used to manufacture metal implants, by using a high-powered laser to scan a powder material bed and fuse particles forming the desired geometry through layer upon layer fabrication . In addition, various modifications are also being attempted on these accepted techniques involving fine gas-atomized powders and laser polishing to improve microstructure, elongation, corrosion resistance, surface finishing, and biocompatibility of the implants. ,, …”

“…11 In addition, various modifications are also being attempted on these accepted techniques involving fine gas-atomized powders and laser polishing to improve microstructure, elongation, corrosion resistance, surface finishing, and biocompatibility of the implants. 8,12,13 Rapidly becoming the go-to technology for fabricating personalized bioimplants, AM, also synonymously termed as 3D printing (3DP) of metallic powder generally employs the laser powder bed fusion principle to melt and add layer by layer, resulting in the desired final construct. Surface texture effects have been proven to be extremely crucial in achieving the final constructs with fatigue resistance.…”

“…The long bone fracture was considered a suitable orthopedic condition to localize the focus of our investigation. Surgical stabilization using metal implants or plates is regular in medical practice, especially for fracture fixation, and such implants are convenient to personalize utilizing AM. , Such implants could be custom modified not just based on the nature of the injury but also could facilitate alterations in surface roughness, topography, and drug loading. , The customized implants also provide flexibility with site specificity of multifunctional coatings, improve osseointegration, and antibacterial deposition. , Such implant was utilized as a model orthopedic device, but it does not limit the potential of fabrication using AM and coating using precision airbrush coating solely on bone support implants alone. This study could be extended to any conventional/3DP implant personalized fabrication, yielding more profound insights into how material surface and coating properties could harness better therapeutic benefits against PSIs.…”