Osseointegration and biocompatibility of different metal implants - a comparative experimental investigation in sheep

Abstract

BackgroundIn the present study, 4 different metallic implant materials, either partly coated or polished, were tested for their osseointegration and biocompatibility in a pelvic implantation model in sheep.MethodsMaterials to be evaluated were: Cobalt-Chrome (CC), Cobalt-Chrome/Titanium coating (CCTC), Cobalt-Chrome/Zirconium/Titanium coating (CCZTC), Pure Titanium Standard (PTST), Steel, TAN Standard (TANST) and TAN new finish (TANNEW). Surgery was performed on 7 sheep, with 18 implants per sheep, for a total of 63 implants. After 8 weeks, the specimens were harvested and evaluated macroscopically, radiologically, biomechanically (removal torque), histomorphometrically and histologically.ResultsCobalt-Chrome screws showed significantly (p = 0.031) lower removal torque values than pure titanium screws and also a tendency towards lower values compared to the other materials, except for steel. Steel screws showed no significant differences, in comparison to cobalt-chrome and TANST, however also a trend towards lower torque values than the remaining materials. The results of the fluorescence sections agreed with those of the biomechanical test. Histomorphometrically, there were no significant differences of bone area between the groups. The BIC (bone-to-implant-contact), used for the assessment of the osseointegration, was significantly lower for cobalt-chrome, compared to steel (p = 0.001). Steel again showed a lower ratio (p = 0.0001) compared to the other materials.ConclusionThis study demonstrated that cobalt-chrome and steel show less osseointegration than the other metals and metal-alloys. However, osseointegration of cobalt-chrome was improved by zirconium and/or titanium based coatings (CCTC, TANST, TAN, TANNEW) being similar as pure titanium in their osseointegrative behavior.

Retained Broken Implants in the Craniomaxillofacial Skeleton

“…Therefore, it is made in combination with other materials such as aluminum and niobium and other trace elements (Ti6AL7Nb). 12 The drill bits are made of grade 316L austenitic stainless steel. The molybdenum it contains gives it a better overall corrosive resistant property and stiffness.…”

Evaluating the osseointegration of nanostructured titanium implants in animal models: Current experimental methods and perspectives (Review)

“…However, dog, sheep, goat, pig, and rabbit models are commonly used to evaluate bone-implant interactions. 57,58 The dog seems to be more promising as animal model for testing bone implant materials, but there are increasing ethical issues relating to the use of dogs in medical research due to their status as companion animals. 59 With regard to bone anatomy, morphology, healing, and remodeling, the pig demonstrates a good likeness to human bone.…”

Biomedical materials and techniques to improve the tribological, mechanical and biomedical properties of orthopedic implants – A review article

“…Chemical composition of 316L SS are shown in Table 2. For long years, 316L SS was considered for medical devices and implants used in trauma surgeries [19], Figure 2 shows examples for biomedical implants made from 316L SS in (a) knee replacement and (b) ankle replacement [2]. 316L is featured for its accepted mechanical and tribological properties.…”