An evaluation of variables influencing implant fixation by direct bone apposition

Abstract

A systematic mechanical and histologic evaluation of design variables affecting bone apposition to various biocompatible materials was undertaken. The variables investigated included material elastic modulus, material surface texture, as well as material surface composition. The implant materials included polymethylmethacrylate (PMMA), low-temperature isotropic (LTI) pyrolytic carbon, commercially pure (C.P.) titanium, and aluminum oxide (Al2O3). Implant surface texture was varied by either polishing or grit-blasting the various materials. Implant surface composition was varied by applying a coating of ultra-low temperature isotropic (ULTI) pyrolytic carbon to the various implants. A total of 12 types of implants were evaluated in vivo by placement transcortically in the femora of adult mongrel dogs for a period of 32 weeks. Following sacrifice, mechanical push-out testing was performed to determine interface shear strength and interface shear stiffness. The results obtained from mechanical testing indicate that for implants fixed by direct bone apposition, interface stiffness and interface shear strength are not significantly affected by either implant elastic modulus or implant surface composition. Varying surface texture, however, significantly affected the interface response to the implants. For each elastic modulus group the roughened surfaced implants exhibited greater strengths than the corresponding smooth surfaced implants. Undecalcified histologic evaluation of the implants demonstrated that the roughened implants exhibited direct bone apposition, whereas the smooth implants exhibited various degrees of fibrous tissue encasement. Thus, for implants utilizing direct bone apposition fixation, it appears that of the parameters investigated, implant surface texture is the most significant.

Hydroxyapatite coating enhances fixation of porous coated implants: A comparison in dogs between press fit and noninterference fit

“…In contrast, the control implants used by Rivero et al (1988) consisted of fiber-metal porous surfaces, which presumably may be considered similar to the porous plasma-sprayed controls used in the present study in terms of anchorage capacity. Using porous-surfaced controls instead of smoothsurfaced controls, skeletal fixation is increased, which again increases the demands on the osteoconductive effect of the relatively smooth surfaced hydroxyapatite implant; the opposite is true for smooth-surfaced controls (Skalak 1983, Carlsson et al 1988b, Thomas and Cook 1985.…”

Stability of dental implants after irradiation with an 830-nm low-level laser: a double-blind randomized clinical study

“…However, the development of new implant surfaces and clinical techniques has enabled a considerable reduction of the initial healing period. Thus, authors proposed variations of the technique for bringing the implant into function and reduce the osseointegration time, by altering the texture of the titanium implant surface [1][2][3]. The use of low-level lasers has been suggested as another way of accelerating and improving the bone tissue healing process [4].…”

Surface characterization of titanium Based dental implants

“…Among all of titanium properties one of the most important is the surface quality [5]. Titanium oxide compounds, present on the surface of commercially pure titanium implants, are responsible for the favorable biological interaction that occur on the bone-fixation interface.…”