Abstract
The aim of this study was to evaluate the microhardness Rockwell and Young s modulus of a new nano-hybrid and nano-fill composite resins exposed to corrosive media. The study was performed on two composite resins, one nano-hybrid and one nano-fill, enamel, dentine, translucent, respectively body shade, of which were made 20 samples (25.0 � 0.1 mm lengths, 10.0 � 0.1 mm widths and 3.0 � 0.1 mm thicknesses), which were immersed in mouthwash for 1 minute per day for 10 days, the rest of the time being stored in artificial saliva. Measurements of Rockwell microhardness and Young�s modulus on samples were made between on the first day, after 6 days and 10 days of immersion in mouthwash comparative with 0 day. The results showed that after immersion in the corrosive environment, both materials had the hardness values changed, but medium values of Rockwell microhardness to nano-fill composite resin were higher than nano-hybride. At the nano-hybride composite resin, it was observed that the enamel and clear translucent groups had the mean values increased after the first day of exposure to mouthwash, compared to the dentine group, which showed a higher mean value after 6 days. At the nano-fill composite resin, for the enamel and body groups were obtained the higher values of HRC after 10 days. For the dentine group, after 6 days, Filtek Ultimate showed the same variation as Harmonize dentine shade. Harmonize composite resin showed higher values of Rockwell microhardness and Young�s modulus for all study groups compared to Filtek Ultimate.
Highlights
The use of coronary restoration materials from composite resins has a wide spread in the world, being indicated on both the front and the lateral teeth [1]
It is noted that the enamel and clear translucent groups had the mean values increased after the first day of exposure to Listerine, compared to the dentine group, which showed a higher mean value after 6 days
At the nano-hybride composite resin, it was observed that the enamel and clear translucent groups had the mean values increased after the first day of exposure to mouthwash, compared to the dentine group, which showed a higher mean value after 6 days
Summary
The use of coronary restoration materials from composite resins has a wide spread in the world, being indicated on both the front and the lateral teeth [1]. Many studies have shown that wear of composite resins is one of the reasons for fracture that can occur at restorations on lateral teeth [3, 4]. These lateral restorations are subject to mechanical forces and chemical changes, such as chewing harsh foods or bruxism [5,6,7]. If the forces applied to composite resin restorations outweigh the mechanical strength of the material, wear may occur, which is most likely to occur in patients applying force higher than average during mastication [8]. The advantages of the Rockwell hardness test are that hardness is read directly and it is good for testing viscoelastic materials [16, 17]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
