Biomed. Eng.-Biomed. Tech. 2018; aop Sebastian Stach, Olga Kędzia, Żaneta Garczyk* and Zygmunt Wróbel Modelling the degree of porosity of the ceramic surface intended for implants https://doi.org/10.1515/bmt-2017-0169 Received September 20, 2017; accepted April 16, 2018 Abstract: The main goal of the study was to develop a model of the degree of surface porosity of a biomaterial intended for implants. The model was implemented using MATLAB. A computer simulation was carried out based on the developed model, which resulted in a two-dimensional image of the modelled surface. Then, an algorithm for computerised image analysis of the surface of the actual oxide bioceramic layer was developed, which enabled determining its degree of porosity. In order to obtain the confocal micrographs of a few areas of the biomaterial, measurements were performed using the LEXT OLS4000 confocal laser microscope. The image analysis was carried out using MountainsMap Premium and SPIP. The obtained results allowed determining the input parameters of the program, on the basis of which porous biomaterial sur- face images were generated. The last part of the study involved verification of the developed model. The model- ling method was tested by comparing the obtained results with the experimental data obtained from the analysis of surface images of the test material. Keywords: Al 2 O 3 ceramic; biomaterials; image processing; modelling; porosity degree; stereometric data analysis; surface of implant. Glossary μ mean value of the Rayleigh distribution a, b subsequent coordinates of circular cross-section centres r radius vector ϕ amplitude of the point at a distance r from the cross- section centre N A number of pores per unit area A total area occupied by the pores A ̅ mean area of pores O ̅ mean perimeter of a single pore V V volume fraction Introduction From a medical point of view, it is very important that materials used as medical devices, both the ones having only external contact with the human body and those intended for use inside the body, are characterised by the highest biocompatibility and fulfil their function best. The area of the material which comes into contact with the body is an essential element of its entire structure, as it is the interface through which interactions of the adjoin- ing structures are possible [1–3]. A very important feature of surfaces is their porosity [4]. Controlling this parameter affects the speed and the quality of osteointegration [5–8]. Moreover, porous materials are ideal as drug carriers [7, 9–13]. The study of material surfaces is so significant that there exist separate disciplines dealing only with material surface layers. They are engineering and surface metrol- ogy. There are several problems that scientists must cope with when studying surfaces, as they are often difficult to access or are very sensitive. For this reason, better tech- niques for surface analysis are constantly being devel- oped [14, 15]. In addition to imaging and surface chemical composition analysis, modelling methods and computer simulations are used. Mathematical modelling is an essential tool used by engineers in every discipline. The need to study the pro- cesses taking place on the surfaces or inside the materials as well as their physico-chemical and mechanical proper- ties is the reason why computer modelling and simulations are so vital. Difficult access to testing equipment, the costs of conducting studies on materials intended for biomedi- cal applications, their duration, the number of experiment repetitions and the structure of materials themselves often limit, and even prevent, research. Modelling enables con- sidering various situations and conditions which materials may experience and analyse their responses without the need for studies involving these materials. The basis for using a model in the study of surface properties and reac- tions taking place on the surface is its verification. For this *Corresponding author: Żaneta Garczyk, Faculty of Computer Science and Materials Science, Institute of Computer Science, University of Silesia in Katowice, Będzińska 39, 41-205 Sosnowiec, Poland, Phone: +48 (0) 32 3689745, Fax: +48 (0) 32 3689863, E-mail: zaneta.garczyk@us.edu.pl Sebastian Stach, Olga Kędzia and Zygmunt Wróbel: Faculty of Computer Science and Materials Science, Institute of Computer Science, University of Silesia in Katowice, Sosnowiec, Poland Brought to you by | Stockholm University Library Authenticated Download Date | 5/20/18 4:43 PM