ABSTRACT
Numerous studies have been conducted on the effect of various beverages on the mechanical properties of tooth-
colored materials, however, little is known about the effects of these materials on composites, particularly newer
types such as nanocomposites. Objectives: This study aimed to evaluate the surface microhardness of two types
of composites, micro-hybrid (point 4) and nanohybrid (premise), after exposure to natural and industrial juices.
Methods: In this experimental study, 90 disc-shaped specimens with a thickness of 2 mm and a diameter of 10
mm were taken from two composites, micro-hybrid Point4 (Kerr) and nanohybrid premise (kerr) (two groups
of 45). Then, the specimens of each group were divided into 5 subgroups of 9 and were immersed for 7 days
for 6 hours in 5 solutions of industrial orange juice, natural orange juice, industrial pomegranate juice, natural
pomegranate juice, and distilled water (control group). Surface microhardness of specimens was measured by
Vickers device at baseline, one day and one week after immersing. Data was measured by ANOVA, repeated
measure test, and independent t-test. A significant level of α was 0.05. Results: The surface microhardness of two
types of composites exposed to beverages was reduced significantly. However, no significant difference was found
between natural and industrial juices in none of the composites. Conclusions: Natural and industrial juices can
affect the surface microhardness of composites, which varies depending on the type of composite and the type of
juice and immersion time.