Short communication Development and design of a novel loading device for the investigation of bone adaptation around immediately loaded dental implants using the reindeer antler as implant bed Alireza Rahimi a,b,c , Reinhard Klein d , Ludger Keilig a,c,e , Marcus Abboud b , Gerhard Wahl b , Christoph Bourauel a,Ã a Endowed Chair of Oral Technology, Dental School, University of Bonn, Welschnonnenstr.17, 53111 Bonn, Germany b Department of Oral Surgery, Dental School, University of Bonn, Welschnonnenstr.17, 53111 Bonn, Germany c Department of Orthodontics, Dental School, University of Bonn, Welschnonnenstr.17, 53111 Bonn, Germany d Department of Computer Science II, University of Bonn, R¨ omerstraße 164, 53117 Bonn, Germany e Department of Preclinical Education and Dental Research, Dental School, University of Bonn, Welschnonnenstr.17, 53111 Bonn, Germany article info Article history: Accepted 10 June 2009 Keywords: Implantology Biomechanics Bone abstract The assessment of the behavior of immediately loaded dental implants using biomechanical methods is of particular importance. The primary goal of this investigation is to optimize the function of the implants to serve for immediate loading. Animal experiments on reindeer antlers as a novel animal model will serve for investigation of the bone remodeling processes in the implant bed. The main interest is directed towards the time and loading-dependant behavior of the antler tissue around the implants. The aim and scope of this work was to design an autonomous loading device that has the ability to load an inserted implant in the antler with predefined occlusal forces for predetermined time protocols. The mechanical part of the device can be attached to the antler and is capable of cyclically loading the implant with forces of up to 100 N. For the calibration and testing of the loading device a biomechanical measuring system has been used. The calibration curve shows a logarithmic relationship between force and motor current and is used to control the force on the implant. A first test on a cast reindeer antler was performed successfully. & 2009 Published by Elsevier Ltd. 1. Introduction Dental implantology is a widely-used and well-tried therapy for a large number of cases of loss of teeth. Integration of implant anchored or implant supported reconstructions of the masticatory apparatus is a good approximation to the ideal of a functional ‘Restutio ad integrum’. It is of particular interest to deal with the magnitude of intraoral forces under physiological loading (mas- tication, swallowing, and so on), the temporal distribution of these events, and the interdependencies of loading, implant healing and bone deformation. The stability of the implant/bone interface has been studied using different experimental and numerical methods (Bidez and Misch, 1992). Clinical and animal experimental studies confirmed that the bony tissue functionally adapts to a changed mechanical environment (Lanyon, 1992). Within certain physiologic limits, bone has the ability to react to a change in the mechanical loading with a change in its structure. This ability to adapt to a changed environment strongly depends on the tissue and cell deformation in the microenvironment of the loaded bone (Wehrbein, 1994). In several animal experimental studies bone modeling and remodeling processes with respect to mechanical loading have been investigated (Duyck et al., 2001; De Smet et al., 2005; Hoshaw et al., 1994). The investigation of bone remodeling phenomena around immediately loaded dental implants in animal experiments causes an enormous stress due to repeated anesthetization of the animals in order to realize a controlled loading protocol. It was the aim of this study to reduce this stress significantly by implementing a novel animal model using the reindeer antler as an implant bed. From biomechanical point of view, the material parameters of cortical and trabecular bone are of highest relevance and have an impact on the results of numerical simulations. Studies performed by Currey (1989) and by Vashishth et al. (1997, 2000, 2003) on living reindeer antlers showed that the elastic and the fracture behavior are similar to that of human bone as long as cortical bone is concerned. A prototype of an autonomous loading simulator was designed, that can be fixed to a reindeer’s living antler and manages the cyclic loading of the implants over a predefined time span. ARTICLE IN PRESS Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jbiomech www.JBiomech.com Journal of Biomechanics 0021-9290/$ - see front matter & 2009 Published by Elsevier Ltd. doi:10.1016/j.jbiomech.2009.06.032 Ã Corresponding author. Tel.: +49 228 287 22332; fax: +49 228 287 22588. E-mail address: bourauel@uni-bonn.de (C. Bourauel). Journal of Biomechanics 42 (2009) 2415–2418