Biomechanical, histological, and ultrastructural analyses of laser micro‐ and nano‐structured titanium alloy implants: A study in rabbit

Abstract

The aim of this study was to evaluate the biomechanical properties and ultrastructure of the bone response of partly laser-modified Ti6Al4V implants compared with turned, machined implants after 8 weeks in rabbit. The surface analyses performed with interference microscopy and electron microscopy showed increased surface topography with micro- and nano-sized surface features as well as increased oxide thickness of the modified surface. The biomechanical testing demonstrated a 270% increase in torque value for the surface modified implants compared with the control implants. Histological evaluation of ground sections of specimens subjected to biomechanical testing revealed ongoing bone formation and remodeling. A histological feature exclusively observed at the laser-modified surface was the presence of fracture in the mineralized bone rather than at the interface between the bone and implant. Transmission electron microscopy (TEM) was performed on Focused Ion Beam (FIB) prepared samples of the intact bone-implant interface, demonstrating a direct contact between nanocrystalline hydroxyapatite and the oxide of the laser-modified implant surface. In conclusion, laser-modified titanium alloy implants have significantly stronger bone anchorage compared with machined implants and show no adverse tissue reactions.

Bone–titanium oxide interface in humans revealed by transmission electron microscopy and electron tomography

“…On the ultrastructural level, the present results in humans are in agreement with previous findings for the same surface treatments in experimental animal models [5,12]. Intimate contact was demonstrated between the laser-modified surface and mineralized bone, while separation and embedding artefacts prevented the preparation of an intact TEM sample of the turned surface.…”

Biomechanical, histological and ultrastructural analyses of laser micro‐ and nano‐structured titanium implant after 6 months in rabbit

“…17,19 In this study, an at least 170% increase remains after 6 months follow-up in rabbit. According to the load deformation plots, even higher removal torque values may be expected since the biomechanical test system per se failed prior to the bone or bone implant interface; the connection between the implant and test machine could not support the loads.…”

Titanium oral implants: surface characteristics, interface biology and clinical outcome

“…The structure of the intact bone/titanium interface is now well characterized down to the nanoscale (Palmquist et al 2008(Palmquist et al , 2009(Palmquist et al , 2010. However, the early cellular and molecular activities determining the early tissue response and bone formation at the bone/ implant interface are not yet fully understood.…”

“…Yet another method to remove the bulk metal leaving the oxide layer has been performed by sawing and grinding (Hemmerle & Voegel 1996), but this method is restricted to thicker coatings such as plasma-sprayed titanium. With FIB microscopy the problem with cutting the implant is overcome and true intact section containing bulk metal, oxide layer and eventual coatings and bone tissue could be prepared (Engqvist et al 2006) and could also be combined with preparation of ground sections for histological analysis (Palmquist et al 2010).…”