%0 Journal Article
%T Micromotion of Dental Implants: Basic Mechanical Considerations
%A Werner Winter
%A Daniel Klein
%A Matthias Karl
%J Journal of Medical Engineering
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/265412
%X Micromotion of dental implants may interfere with the process of osseointegration. Using three different types of virtual biomechanical models, varying contact types between implant and bone were simulated, and implant deformation, bone deformation, and stress at the implant-bone interface were recorded under an axial load of 200£¿N, which reflects a common biting force. Without friction between implant and bone, a symmetric loading situation of the bone with maximum loading and displacement at the apex of the implant was recorded. The addition of threads led to a decrease in loading and displacement at the apical part, but loading and displacement were also observed at the vertical walls of the implants. Introducing friction between implant and bone decreased global displacement. In a force fit situation, load transfer predominantly occurred in the cervical area of the implant. For freshly inserted implants, micromotion was constant along the vertical walls of the implant, whereas, for osseointegrated implants, the distribution of micromotion depended on the location. In the cervical aspect some minor micromotion in the range of 0.75£¿¦Ìm could be found, while at the most apical part almost no relative displacement between implant and bone occurred. 1. Introduction Micromotion of dental implants has been defined as minimal displacement of an implant body relative to the surrounding tissue which cannot be recognized with the naked eye [1] (Figure 1). Various authors have shown that excessive micromotion may interfere with the process of osseointegration of dental implants [2, 3]. Although exact data are missing, it has been postulated that micromotion between implant and bone must not surpass a threshold value of 150 micrometer (¦Ìm) for successful implant healing [4¨C6]. Figure 1: Single tooth implant used for replacing the first molar in the lower left mandible. An axial force acting on the occlusal surface of the restorations may displace the implant relative to the surrounding bone. In traditional loading protocols, where implants are allowed to heal undisturbed for periods of several months, the issue of implant micromotion is of limited importance. With the advent of modern treatment concepts including early and immediate loading of dental implants [7, 8], with implants being restored early in the healing phase, the issue of implant micromotion has gained significant importance [4, 5]. Numerous reports trying to relate clinical parameters to the phenomenon of implant micromotion can be found in the dental literature [8¨C11]. The nonuniform nomenclature,
%U http://www.hindawi.com/journals/jme/2013/265412/