Experimental assessment of the influence of wear of nano-filled filling materials on the density of the contact point

Abstract

High-quality treatment of caries of the proximal surfaces of the teeth involves not only the anatomical restoration of the contact surface of the tooth, but also the restoration of the necessary interdental pressure to prevent food from entering the interdental spaces. The physiological mobility of teeth during chewing leads to wear of filling materials in the proximal area and increases the risk of the formation of weak contact points, therefore, when restoring class 2 cavities, composite materials with high wear resistance should be used. Aim — to conduct a comparative experimental analysis of the influence of the degree of wear of dental nanocomposites of domestic and foreign production on the amount of pressure in the area of proximal contact.
Materials and methods.
To conduct the study, a test stand was developed and patented, simulating the impact of an adjacent tooth on the material that replaces the proximal wall of the causative tooth. The developed bench was modified with a strain gauge to determine the effect of material wear on the final density of the proximal contact. For a comparative assessment of nanocomposites, representatives of domestic and foreign manufacturers were selected: DentLight Nano (VladMiVa, Russia), Harmonize (Kerr, USA), and Estelite Sigma Quick (Tokuyama, Japan).
Results.
A comparative analysis of the wear of the presented composites did not reveal significant differences in the degree of abrasion of the material. On average, over 10 hours of operation of the stand (simulating 2 years of a filling in the oral cavity), a pressure change of 0.2—0.3 N was recorded. A detailed analysis of the nature and rate of wear showed that the DentLight Nano composite has the best strength characteristics, due to the absence of chip formation on the surface of the restoration.
Conclusion.
Wear of composite materials, regardless of the initial density of the proximal contacts, will lead to a change in the pressure of the contact points of 0.2 N every 2 years. The Dent Light Nano composite material demonstrates optimal wear resistance to horizontal loads, which allows it to be used to restore the proximal walls of teeth in class 2 restorations.