The comparison of AFM surface texture parameters of dental nanohybrid composite polished by two different procedures

 Tijana Lainović ¹, Larisa Blažić ^1,2, Marko Vilotić ³, Dragan Kukuruzović ³, Damir Kakaš ³

¹ Faculty of Medicine, School of Dentistry, University of Novi Sad, Novi Sad, Serbia

² Clinic of Dentistry of Vojvodina, Novi Sad, Serbia

³ Faculty of Technical Sciences, University of Novi Sad, Novi Sad, Serbia

Our interdisciplinary research team consists of two groups of researchers from the University of Novi Sad, Serbia:

The team from the Medical Faculty, School of Dentistry (Prof. Dr. Larisa Blažić and research assistant Tijana Lainović) and the team from the Faculty of Technical Sciences, from the Laboratory for surface engineering and nanotechnology (Prof. Dr. Damir Kakaš and research assistants Marko Vilotić and Dragan Kukuruzović). Our main research topics include: oral bionanomaterials characterization, nanotechnology applications in dentistry and determination of microstructure and characterization of surface texture of dental materials on the nanometer scale. Successful cooperation between our teams has resulted in many publications, and there is a great potential for further work and research results, as well as the willingness of our team to collaborate with researchers at the international level.

Commercially available and the most widely used oral bionanomaterials in dental practice are resin-based composites containing oxide nanoparticles. Dental nanostructured composites are tooth-colored restorative materials for reconstruction of damaged tooth structure. These materials are synthesized in order to improve overall materials properties, including: mechanical, physical, optical and aesthetic characteristics. Nanostructured composites in dentistry can be divided in two groups: nanofilled and nanohybrid composites. Nanofilled materials are filled only with the nanosized inorganic particles, and nanohybrid composites consist of micro-fillers with embedded nanometer-sized particles.

The aim of this study was to determine the AFM texture parameters of dental nanohybrid composite and to compare the influence of two different dental polishing protocols on surface roughness of this restorative material.

Dental nanohybrid resin-based composite (IPS Empress Direct, Ivoclar Vivadent) was tested in this study. The samples were polished by two dental polishing protocols: multi-step (Super Snap, Shofu) and one-step system (OneGloss, Shofu). Samples were examined by Veeco di CP-II Atomic Force Microscope, in contact mode with CONT20A-CP tips. 1 Hz scan rate and 256 × 256 resolution were used to obtain topography on a 90 × 90 µm scanning area. Average roughness (R_a) and maximum peak-to-valley distance (R_p-v) were analyzed and compared between samples.

Multi-step polishing protocol produced significantly smoother surface and lower roughness than one-step polishing protocol. Although it is intended for reduction of clinical chair-time, one-step polishing protocol did not meet the high quality restoration demands of modern dental practice. The adequate dental polishing method needs to be used in order to take advantages of nanostructured materials and to achieve the best clinical outcomes.

Keywords: dentistry, nanostructured material, dental nanocomposite, AFM, surface texture, surface roughness

Acknowledgments

Supported by: Project TR 035020 (Larisa Blažić, Tijana Lainović) and Project III-45006 (Damir Kakaš, Dragan Kukuruzović, Marko Vilotić) the Ministry of Education, Science and Technological Development, Republic of Serbia

The authors would like to thank Ivoclar Vivadent product distributers in Serbia, and Mikodental, Šabac – general dealers of Shofu, Japan for Serbia, for the material support.