engleski

Loading properties of implant-abutment assemblies: an interferometric analysis – a pilot study

Background: The increase in failure rates following the initial dental implant loading phase exemplifies the importance of undestanding implant loading properties. Implant biomechanics associates load distribution with implant size and shape. Researchers have analysed the peri-implant bone stress ; however, they seldom investigated the changes in the implantabutment assembly itself. Most of the analyses were based upon virtually simulated experiments, thus lacking empirical data pertinent for real life performance. Digital holographic interferometry is a method that enables direct insight in surface deformation upon loading in real world environment with submicron accuracy. To this date, there has not been an interferometric study that thoroughly analysed loading properties of different implant-abument assemblies. Aim/Hypothesis: The purpose of this preliminary study was to analyse the deformation in the cervical portions of two implant-abutment assemblies under incremental axial loading by means of digital holographic interferometry and compare them based on their diameters. Different implant- abutment brands are to be analysed in the final study. Material and methods: Experiments included a dental implant (AstraTech, Astra Tech AB, M€olndal, Sweden), represented by a 3.5 and 5.0 mm diameter implant-abutment assembly. A quasi-Fourier setup with a Spectra-Physics 25 mW heliumneon laser light source (wavelength: 632.8 nm) was used for digital holographic interferometry measurements. The object beam was expanded and collimated to reflect from a part of the base (clamping device), the exposed cervical 5 mm of an implant and the abutment. An implant-abutment assembly was preloaded with a 10 N force in the high precision implant loading device. After obtaining the first hologram, the assembly was loaded with a desired force and recorded again. Both holograms were superimposed and an interferogram was reconstructed. This procedure was repeated throughout the whole process of incremenal axial loading for the following forces: 20 N, 30 N, 40 N, 50 N, 60 N, 70 N, 80 N, 90 N, 100 N, 110 N, and 120 N. Each series of measurements was repeated three times for each assembly, with complete dismantling of the implant-loading device in between series. Statistical analysis was performed using linear mixed effect modelling in R’s lme4 package. Results: Implant-abutment assemblies exhibited a linear deformation pattern. An increase in deformation upon applying incremental forces was significantly higher in the narrow compared to the wide implant-abutment assembly (P < 0.01). Conclusions and clinical implications: Digital holographic interferometry is a suitable method for load distribution analysis in implant-abutment assemblies.

oral implantology ; digital holographic interferometry ; loading

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