title: Understanding mechanisms and factors related to implant fixation; a model study of removal torque.
abstract: Osseointegration is a prerequisite for achieving a stable long-term fixation and load-bearing capacity of bone anchored implants. Removal torque measurements are often used experimentally to evaluate the fixation of osseointegrated screw-shaped implants. However, a detailed understanding of the way different factors influence the result of removal torque measurements is lacking. The present study aims to identify the main factors contributing to anchorage. Individual factors important for implant fixation were identified using a model system with an experimental design in which cylindrical or screw-shaped samples were embedded in thermosetting polymers, in order to eliminate biological variation. Within the limits of the present study, it is concluded that surface topography and the mechanical properties of the medium surrounding the implant affect the maximum removal torque. In addition to displaying effects individually, these factors demonstrate interplay between them. The rotational speed was found not to influence the removal torque measurements within the investigated range.
authors.affiliation: Department of Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Box 857, SE-501 15 Borås, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden. Electronic address: patrik.stenlund@sp.se.
authors.forename: Patrik
authors.initials: P
authors.lastname: Stenlund
authors.affiliation: BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden; Department of Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, 464-8603 Nagoya, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Murase
authors.affiliation: Glafo - the Glass Research Institute, PG Vejdes Väg 15, SE-351 96 Växjö, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Stålhandske
authors.affiliation: Department of Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Box 857, SE-501 15 Borås, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden.
authors.forename: Jukka
authors.initials: J
authors.lastname: Lausmaa
authors.affiliation: BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden; Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Box 412, SE-405 30 Göteborg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Palmquist
mesh_terms: D016348:Osseointegration; D011140:Polyurethanes; D019736:Prostheses and Implants; D013499:Surface Properties; D013696:Temperature; D019415:Torque
chemical_list: D011140:Polyurethanes
keywords: Implant fixation; Removal torque; Surface roughness; Titanium implant