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

Abstract

Short-term, experimental studies of partly laser-modified implants with nano-scale surface topographical features have recently shown a considerable increase in the biomechanical anchorage to bone. The aim of this study is to evaluate the biomechanical and bone-bonding ability of partly laser-modified implants compared with machined implants after a healing period of 6 months in a rabbit model. The results showed a 170% increase in removal torque. Histology and scanning electron microscopy demonstrated osseointegration for both implant types, but also revealed a different fracture pattern at the interface and in the bone. Transmission electron microscopy and chemical analysis showed coalescence between mineralized tissue and the nano-structured surface of the laser modified implant. Taken together, the results indicate that nano-structured surfaces promote in vivo long-term bone bonding and interface strength.

Reliability evaluation of alumina-blasted/acid-etched versus laser-sintered dental implants

“…Such results are likely due to the higher surface roughness and thereby mechanical interlocking between bone and laser-sintered/ textured implants compared to implants that are first machined and then textured by a variety of methods (Coelho et al 2008). Other studies have also shown acceptable osseointegration of laser-treated surfaces [8,13]. Since previous work has reported the appropriate biocompatible and osseoconductive properties of laser-treated and laser-sintered implants, the present study aimed to investigate whether laser-sintered fabricated implants would present different reliability and failure modes compared to current industry standard alumina-blasted/acid-etched implant.…”

“…Transmission electron microscopy and chemical analysis showed coalescence between mineralized tissue and the surface of the lasermodified implant [13]. Recently, improved biomechanical response has been reported for laser-sintered compared to alumina-blasted/acid-etched implants at early times (1 and 6 weeks in vivo) [14].…”

“…While the ISO 14801:2007 was created with the aim to standardize the testing procedures and data presentation in fatigue of dental implants, it has been shown that results produced by such method should be interpreted with caution. The wide range of testing parameters allowed in the ISO 14801:2007 regarding testing frequency (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), environment (water or dry when testing above 15 Hz), and amount of cycles (2 or 5 million, depending on chosen frequency) have shown that a very different failure probability distribution may result [20] as well as failure modes (transgranular in dry compared to intergranular in wet conditions) [21]. In addition, testing of one sample could take 12 days when carried on 2 Hz.…”

High-resolution three-dimensional probes of biomaterials and their interfaces

“…This oxide layer can further be modified to enhance bone bonding by altering its surface topography. Both micro and nanostructured surfaces have been shown to improve bone growth and cellular activity on the surface of titanium [58][59][60]. In work with our collaborators, laser modification of a titanium screw (Biohelix, Brånemark Integration AB, Sweden) has resulted in a titanium dioxide surface with a unique nanotopography (figure 4a) [58].…”

Nanostructured model implants for in vivo studies: influence of well-defined nanotopography on de novo bone formation on titanium implants

“…34 The fact that nanostructured surfaces promoted long-term bone bonding and interface strength in vivo, as determined by coalescence between mineralized bone and the nanostructured surface and a substantial increase in removal torque, is of clinical importance. 35 Furthermore, a previous in vivo study of electropolished titanium implants with nanosized hydroxyapatite particle modification compared with a non-coated control showed greater bone contact for the modified surface after 4 weeks of healing. 36 Acid-etched microtopography with irregular, discrete, 20-40 nm hydroxyapatite particles has also been reported to enhance the strength and direct bone bonding of osseointegration.…”