Effect of Shot Peening on the Mechanical Properties and Cytotoxicity Behaviour of Titanium Implants Produced by 3D Printing Technology

Abstract

Structural discontinuities characterize the implants produced directly from metal powders in 3D printing technology. Mainly, the surface defects should be subjected to procedures associated with surface layer modification (likewise shot peening) resulting in the increase of the implant service life maintaining optimal biocompatibility. Therefore, the purpose of the present study was to investigate the effect of type of shot used for the peening process on the Ti-6Al-4V implants functional properties as well as the biological properties. The components were produced by DMLS (direct metal laser sintering) additive technology. The surfaces of titanium specimens have been subjected to the shot peening process by means of three different shots, i.e., CrNi steel shot, crushed nut shells, and ceramic balls shot. Then, the specimens have been subjected to profilometric analysis, microhardness tests, and static strength testing as well as to the assessment of biocompatibility in respect of cytotoxicity using human BJ fibroblasts. The shot peening process causes the strengthening of surface layer and the increase of strength parameters. Furthermore, the test results indicate good biocompatibility of surfaces being tested, and the effect of shot peening process on the titanium alloy cytotoxicity is acceptable. At the same time, most favourable behaviour in respect of cytotoxicity has been found in the case of surfaces modified by means of ceramic balls > nut shells > CrNi steel shot correspondingly.

Profile and Areal Surface Parameters for Fatigue Fracture Characterisation

“…Researchers have studied the characteristics of fractured surfaces using observational tools, from macro- to nanoscale [ 13 , 14 , 15 , 16 , 17 ]. Unfortunately, even though advanced methods such as optical coherence tomography [ 18 ], scanning acoustic microscopy [ 19 ] or energy response approach based on strain energy density histories during variable loading [ 20 , 21 ] are described in the literature, usually simple-fracture qualitative analysis conducted with scanning electron microscopy is employed for the evaluation of surface fractures resulting from impact [ 22 , 23 ], tensile strength [ 24 , 25 ], fatigue [ 5 , 19 ], ultra-high fatigue [ 26 ], adhesion testing [ 27 ] or even wear damage description [ 28 , 29 ]. However, few studies have investigated the use of profile and surface roughness as a tool for fatigue fracture characterisation.…”

Bending Behaviour of Polymeric Materials Used on Biomechanics Orthodontic Appliances

“…Reliability can be understood as the ability to perform intended functions in relation to time in certain conditions of use [14][15][16][17][18][19]. In this approach, reliability is associated with durability which is also the subject of biomedical materials testing [6,7,[20][21][22][23][24][25][26][27][28]. Reliability of mechanical strength is understood differently [29][30][31][32] than reliability referred to as failure rate during use.…”

Effect of Yttrium and Rhenium Ion Implantation on the Performance of Nitride Ceramic Cutting Tools

“…Due to its extraordinary properties, titanium and titanium alloy Ti-6Al-4V is widely used in various branches of industry [ 1 , 2 , 3 ], such as aircraft, automotive industry and optoelectronics [ 4 , 5 ], or medicine [ 6 ]. In the field of orthopedics and in dental prosthetics, titanium found a wide range of applications [ 6 , 7 ]. Its high corrosion resistance is attributed to passive layers consisting of amorphous TiO 2 , formed on the surfaces [ 8 , 9 , 10 ].…”