The analysis of contemporary areal functional surface parameters of functional parts in any system of elements, that are in contact with each other, is essential for the understanding of their frictional behaviour. Oral environment is a specific tribological system where a tooth or a tooth-restoration is exposed to the cyclic mechanical, thermal, and pH changes. 3-D areal texture parameters of tooth replacing materials are of a great importance for prediction and understanding of the materials’ tribological properties during their functional use.

The aim of this study was to conduct a detailed AFM morphological analysis of contemporary dental nanocomposites and to calculate specific 3-D surface texture parameters, after four dental polishing protocols.

Two representative materials were chosen for testing: nanohybrid (Filtek Z550, 3M ESPE – FZ550) and nanofilled (Filtek Ultimate Body, 3M ESPE – FUB). The polymerized composite samples were polished by four different dental polishing procedures: multi-step (MSP), single-step (SSP), multi-step followed by diamond paste (MSP+D), and single-step followed by diamond paste (SSP+D). For the texture analysis the atomic force microscopy was used (Veeco di CP-II). Using the software packages: Mountains Map^® 7 (Digital Surf, Besançon, France,  available from: http://www.digitalsurf.fr) and Gwyddion 2.28 (available from: http://gwyddion.net/), the depth histograms, volume surface parameters, peak count histograms, watershed segmentation algorithms, average power spectral density were calculated to describe the 3-D surface properties of tested specimens.

These parameters offered the possibility of a more profound understanding of the structure-related functional properties of the surfaces of tested materials. The MSP created a more favourable surface texture on both tested materials. It had narrower height distribution and volume surface parameters which indicated the lower wear probability of materials polished by MSP than the SSP. The number of motifs after the watershed segmentation was the highest on the samples polished by MSP, due to the presence of fine surface irregularities. SSP created lower number of motifs, by cutting the surface details and creating deep and wide grooves, plane aspects of dales or hills. MSP or MSP+D mostly created more isotropic surface texture, which indicates that the MSP can be considered as a reliable method for dental composites polishing in comparison with the SSP or SSP+D.

Supported by Project TR 035020 and Project III-45016 of the Ministry of Education, Science and Technological Development of Republic of Serbia; and 3M (East) AG company and Mikodental – Shofu, Japan for Serbia.

Figures:

Fig. 1. AFM image of FUB polished by MSP

Fig. 2. AFM image of FUB polished by SSP

Fig. 3. AFM image of FUB polished by MSP+D

Fig. 4. AFM image of FUB polished by SSP+D

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EMC Abstracts - https://emc-proceedings.com/abstract/3-d-areal-functional-parameters-extracted-from-afm-data-of-polished-dental-tooth-restorative-nanocomposites/