Enhancing osseointegration by site-specific laser modification of titanium implants: comparative and correlative analyses of different parameters of bone-implant integration

Field: Medicine (Health Sciences)

Event Abstract Back to Event Enhancing osseointegration by site-specific laser modification of titanium implants: comparative and correlative analyses of different parameters of bone-implant integration Omar Omar1, 2, Martin L. Johansson3, Furqan A. Shah1, 2, Hanna Simonsson3, Lena Emanuelsson1, 2, Anders Palmquist1, 2 and Peter Thomsen1, 2 1 Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Department of Biomaterials, Sweden 2 BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Sweden 3 Oticon Medical, Sweden Introduction: Osseointegrated implants have proven successful in several applications, including bone-anchored hearing aids. The first generation of implants had a machined surface with long-term, well-documented but rather slow osseointegration. Higher anchorage can be achieved by roughening the implant surface. This study employed a selective laser-treatment in order to produce site-specific surface modification confined to the thread valley, leaving the majority of the implant as machined. The aim was to compare the early bone response to machined titanium implants with and without selective laser-modification with regards to biomechanical anchorage, bone growth and ultrastructure. Material and Methods: Screw-shaped implants were machined from commercially pure titanium. Implants were selectively laser-modified in the thread valleys using Nd:YAG laser. The results of the material characterization are summarized in Fig. 1. The laser-treated (test) and machined (control) implants were installed bilaterally in the tibiae of 10 New Zealand rabbits. Baseline implant stability quotient (ISQ) was recorded using resonance frequency analysis (RFA) (n=10). After 8 weeks, ISQ was recorded (n=10) and the removal torque (RTQ) was measured (n=10). The implants with surrounding tissues were dissected en bloc, resin embedded and bisected. Histomorphometry (n=10) was performed on ground-sections, to quantify bone area (BA) and bone-implant contact (BIC) considering all threads. Ultrathin sections for transmission electron microscopy (TEM) were prepared by focused ion beam scanning electron microscopy (FIB-SEM). The Wilcoxon’s signed rank test and Spearman’s rho correlation analysis were used for statistical analysis; p < 0.05 was considered statistically significant. Results and Discussion: The RTQ for the laser-modified implants was 153% higher than the machined implants (Fig. 2A). The load deformation plot (data not shown) suggested a fracture-like deformation for the laser-modified implants. This was supported by histological observations of fracture lines in the bone in the laser modified thread valleys (Fig. 2B–C). In contrast, a gradual separation of the implant surface from bone was observed for machined implants (Fig. 2D–E). No differences in ISQ (Fig. 2F) or histomorphometry (data not shown) were detected between machined and laser implants. Correlation analyses revealed strong positive correlation for the RTQ with bone-to-implant contact in the thread valley (Table I). Ultrastructural analysis showed a direct coalescence between the laser-modified surface and bone in the thread valley (Fig. 2G). Altogether, the results suggested that RTQ had the highest sensitivity to measure implant stability and that the increased stability of the laser-modified implant is attributable to direct bone bonding with the site of laser modification. Conclusions: Selective laser modification for site-specific micro/nano-roughness in the thread valley, promotes biomechanical anchorage of the whole implant during the early period of osseointegration. ISQ correlates with the amount of bone growth around the implant, however, fail to measure the biomechanical anchorage. The biomechanical anchorage, as determined by RTQ, appeared to be strongly dependent on the degree of bone-implant contact, and possibly bonding, particularly in the region of the implant surface modification. This study was supported by the Swedish Research Council (K2015-52X-09495-28-4), BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, the Region Västra Götaland and the Hjalmar Svensson Research Foundation. Keywords: in vivo, Implant, Surface modification, ENT Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomaterials evaluation in animal models Citation: Omar O, Johansson ML, Shah FA, Simonsson H, Emanuelsson L, Palmquist A and Thomsen P (2016). Enhancing osseointegration by site-specific laser modification of titanium implants: comparative and correlative analyses of different parameters of bone-implant integration. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00127 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Omar Omar Martin L Johansson Furqan A Shah Hanna Simonsson Lena Emanuelsson Anders Palmquist Peter Thomsen Google Omar Omar Martin L Johansson Furqan A Shah Hanna Simonsson Lena Emanuelsson Anders Palmquist Peter Thomsen Google Scholar Omar Omar Martin L Johansson Furqan A Shah Hanna Simonsson Lena Emanuelsson Anders Palmquist Peter Thomsen PubMed Omar Omar Martin L Johansson Furqan A Shah Hanna Simonsson Lena Emanuelsson Anders Palmquist Peter Thomsen Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.