Perspectives of images superimposition principle use during the registration of peri-implant bone dynamic changes.

Abstract

Background. Analysis of peri-implant bone level changes with the use of superimposition principle is argumented by the specific remodeling process of bone structure under various mechanical loads, and justified by the possibilities of graphic images modalities provided by cone-beam computer tomography. Objective. To provide a retrospective analysis of superimposition principle use in dental practice according to the literature data and to develop adapted approach for peri-implant bone changes evaluation by a graphical investigation algorithm of CT scanning results. Methods.Retrospective analysis of the literature was provided with the use of Google Scholar and keyword search principle using words "superimposition", "dental", "tomography" as main references. DICOM-files of patients who have undergone the procedure of dental implantation at the University Dental Clinic (Uzhgorod National University) were used as objects of the experimental study. Files of .dcm format were converted to the .stl format with the use of Invesalius 3 software (CentrodeTecnologiadaInformaçãoRenatoArcher). Superimposition of STL model was provided in Geomagic®Control™ by the function of ‘‘Bestfitalignment”. Individualized volumetric bone loss at peri-implant region was calculated by the formula: Vind = Vc.u. * HU (where Vind–an individual volume reduction of bone tissue, an indicator of bone resorption level defined by superimposition principle, and HU - an indicator of bone density defined in terms of Hounsfield units). Results. Principle of image superimposition is a partial representation of the superposition method, which allows to impose the studied areas with the possibility of their segmental analysis and discrete comparison for the visualization and objectification of changes in a particular anatomical region. Proposed algorithm of STL files superimposition formed from DICOM results of CT-scanning provides an adaptive approach for evaluation of individual volume reduction of bone tissue in conventional units due to the offered novel formula. Conclusion. Practical use of super imposition principle can be effective during the verification of residual ridge changes after dental implantation with the ability to register dynamics of bone remodeling processes at different time’s periods after iatrogenic intervention. Thus, the use of such evaluation algorithm may not only deploy settings of bone loss at the peri-implant area, but also expands the opportunities to evaluate the effect of comprehensive iatrogenic and biological factors on circular bone loss around dental implant, which can be registered only with use of computed tomography method.