Wear behavior at margins of direct composite with CAD/CAM composite and enamel

Abstract

Objectives The aim was to investigate the two-body wear at the marginal area between direct filling composites and substrate of CAD/CAM composites or enamel. Materials and methods Flat specimens were prepared from CAD/CAM composites (CERASMART 270 and SFRC CAD) and bovine enamel. A box-shaped cavity cut into CAD/CAM composites and enamel surfaces was made. The prepared cavity in CAD/CAM composites was treated with a primer, while in enamel, the cavity was treated with an adhesive. Three conventional composites (Universal Injectable, G-aenial A’Chord, and Filtek Bulk Fill) and one short fiber composite (everX Flow) were placed and cured in the prepared cavities. A two-body wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. The specimens (n = 5/per group) were positioned to produce wear (load = 20 N) across the marginal area between filling composites and substrates. The wear depth was analyzed using a 3D optical profilometer. SEM was used to evaluate the wear behavior and margins between the filling and substrate materials. Results All composites used displayed different wear behavior (20–39 µm) (p < 0.05). The highest wear values were recorded for A’Chord and Filtek, while the lowest values were for Injectable and CERASMART 270. The data analysis showed that the wear behavior of substrate materials depends on the filling materials used at margins (p < 0.05). The marginal breakdown was seen only between bovine enamel and filling composites. Conclusions The use of the two-body wear simulation method revealed important information about the behavior of the filling composites at the marginal area with CAD/CAM composites or bovine enamel substrates. Clinical relevance The marginal breakdown related to the material combination at the bonding region.

Effect of different beverages and polishing techniques on colour stability of CAD/CAM composite restorative materials

“…Thereby, microfibres filler loading had no negative impact on the colour stability of the SFRC CAD. This finding aligns with prior research that showed favourable surface and optical properties of SFRC CAD when compared to various particulate-filled composites [ 11 , 14 , 16 ]. Within the mentioned research, the microfibres of the SFRC CAD did not protrude from surface after polishing or wear test; instead, they were polished in the resin matrix, resulting in often a uniformly smooth surface.…”

“…To achieve a more acceptable stress distribution between restoration and underlaying tooth structure, some researchers [ 8 , 9 ] advocate using materials having an elastic modulus similar to that of dentin. Due to elastic modulus, wear characteristics, colour integration, and malleability in thin layers, composite-based CAD/CAM materials have become increasingly common over the past 10 years [ 10 , 11 ]. Compared to traditional light-cured resin composites, CAD/CAM composites have significantly higher monomer conversion due to the high temperature and pressure during polymerisation, resulting in composites with superior mechanical properties and biocompatibility [ 2 ].…”