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An objective methodology for evaluating the mechanical compliance of osteotomy preparations: Part 1 - Final report project "Tools, Technology, Research for implant placement with guided system" Authors: B. Truyen, C. Boca and J. Cornelis Publisher: ETRO-IRIS Research Group, Faculty of Engineering, Vrije Universiteit Brussel, Belgium Publication Date: Dec. 2009
Abstract: Extensive trauma during the osteotomy preparation is considered a major cause of implant failure because thermal as well as mechanical factors contribute to the formation of necrotic tissue, thereby affecting implant stability. Thermonecrosis, resulting from the frictional heat generated during implant surgery is known to compromise severely bone regeneration. In an extensive literature, differences in heat generation were related to multiple factors, including drill design, drill loading, rotational speed, drill wear, preparation depth, continuous versus intermittent drilling, and the use of graded implant drills. Another aspect, that received comparatively little attention, is the impact of the drill design and material composition on the mechanical tolerances of the osteotomy preparation. Especially when preparations are performed on angulated surfaces, oblique loading forces are developed that tend to bend the implant drill, which will not only affect the orientation, but also the shape and volume of the excavation volume. Undue loss of bone material as a result of drill bending directly compromises the primary implant stability, while deviations in the orientation may impede the accuracy of the implant planning. Drill wandering and vibrations during the initial seating of the implant drill into the cortical bone, often caused by blunting or an inappropriate drill design, may also contribute to an enlargement of the osteotomy volume. The aim of this in vitro study was to compare 3 commercially available stainless steel implant drills (Ankylos, Nobel Biocare, Straumann) and a newly released zirconium oxide implant drill system (2Ingis) for the effects of oblique drill loading on the mechanical specifications of the osteotomy preparation. To this end, an objective methodology was developed to quantitatively evaluate the mechanical compliance of osteotomy preparations, based on a combination of X-ray Micro Computed Tomography (XMCT) imaging and a mathematical modeling.
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