A histological and histomorphometrical investigation of fluorapatite, magnesiumwhitlockite, and hydroxylapatite plasma‐sprayed coatings in goats

Abstract

Plasma-sprayed ceramic coatings of fluorapatite (FA), magnesiumwhitlockite (MW), and hydroxylapatite (HA), and noncoated Ti-6Al-4V alloy (Ti) implants were evaluated histologically and histomorphometrically in a goat animal study. Cylindrical Ti-6Al-4V plugs were plasma-spray-coated with FA, MW, and HA. Noncoated, grit-blasted Ti plugs served as controls. The plugs were implanted into the right femur and left humerus of 20 adult goats. The results were evaluated using descriptive histology and histomorphometry. The histomorphometry consisted of measurements of bone apposition and coating thickness. The results demonstrated that FA showed a high amount of bone apposition without signs of degradation or dissolution. MW showed considerable reduction in thickness and at 12 weeks an adverse tissue reaction. However, at 25 weeks the amount of bone apposition was significantly increased compared with the 12-week implants. HA revealed considerable and progressive reduction in thickness and at 25 weeks a lower amount of bone apposition than FA and MW. At 12 weeks the Ti implants did reveal bone apposition, although frequently localized fibrous tissue was visible. At 25 weeks the Ti implants did not differ in bone apposition from the HA implants. Further studies are necessary on the effect of degradation or dissolution of HA on the compatibility with bone.

Organic–Inorganic Surface Modifications for Titanium Implant Surfaces

“…Since then numerous reports have been published about the osteoconductive properties of CaP-coated implants (osteoconduction refers to the ability of a biomaterial to support the growth of bone over its surface). These CaP coatings are described to induce an increased bone-to-implant contact (38,(43)(44)(45), to improve the implant fixation (46), and to facilitate the bridging of small gaps between implant and surrounding bone (47,48). As an example of the osteoconductive properties of CaP coatings, Fig.…”

Paired evaluation of calvarial reconstruction with prototyped titanium implants with and without ceramic coating

“…Several studies have demonstrated these properties either with osteoblast cultures 5,20 or with in vivo experiments 3,4,11 .…”

“…It is generally reported in the literature that ceramic coatings improve the osseointegration of metallic scaffolds by promoting the filling of gaps between bone and implant 12 , enhancing bone contact with the implant surface 11,28 and possessing osteoinductive properties 29,30 . However, the results of experimental studies comparing titanium implants with and without ceramic coatings have conflicting results, with evidence either of lack of benefit [31][32][33][34][35] or superior results 11,12,28,36 with bone growth acceleration 37 .…”

“…However, the results of experimental studies comparing titanium implants with and without ceramic coatings have conflicting results, with evidence either of lack of benefit [31][32][33][34][35] or superior results 11,12,28,36 with bone growth acceleration 37 . Taking together the results of push-out tests and SEM images observations, it was not possible to demonstrate a benefit of the β-TCP coating.…”

“…The ceramic coating of metallic implants functions as a transition layer between bone tissue and the non-physiological metal surface, enhancing the contact and conducting bone growth along the surface of the implant 10 . Calcium phosphate coatings are reported to increase contact between bone and implant 11 , and to enhance implant fixation, including a facilitation of bone growth over gaps between the two surfaces 12 .…”