Effect of Habitual intakes on Hardness and Color of Resin Composites

Author(s): Khalid M. Abdelaziz and Ahmed A. Saleh

Background: Both surface hardness and color stability are among the most important physical factors that govern the success of different composite restoratives.

Aim: This in vitro study aimed to evaluate both surface hardness and color change in different resin composites following their immersion in different media of some habitual intakes.

Methods: One hundred disc specimens were constructed in 2 groups out of methacrylate (Tetric N-Ceram Bulk Fill, Ivoclar Vivadent) and siloranebased (Filtek P90, 3M ESPE) composites (n=50 each). Specimens of each group were subjected to an interrupted immersion in 5 different media (subgroups 1-5, n = 10), water (control), natural saliva, alcohol, lime juice and khat extract for 4 weeks. Vickers hardness of all specimens was assessed on a micro-hardness tester under a load of 50g for 10s. The color parameters (L*, a* and b*) of each specimen were measured before and after immersion. The difference in specimens’ color (ΔE) was calculated according to CIE formula. The collected data for all subgroups were statistically analyzed using 1-Way ANOVA and Tukeys' comparisons at α = 0.05 to stand on the significance of differences detected between the tested variables.

Results: No difference in hardness value was recorded between composite groups (P > 0.05). In comparison to the control subgroup, no significant differences were noticed in the hardness values of composites in subgroups 2-4 (P > 0.05). A significant reduction in hardness values were recorded for composite specimens stored in khat extract (P < 0.05). All composite specimens showed different degrees of color change with no significant differences between groups (P > 0.05). Specimens in subgroups 1-4 had similar visually perceptible color change (1< ΔE <3.3), while those in Subgroup 5 showed higher clinically unacceptable color change (ΔE >3.3) in comparison to other subgroups (P < 0.05).

Conclusion: Silorane-based resin composite present comparable behavior to that of Bulk-fill methacrylate-based composite in different media. All the tested intakes have no adversity on composites’ hardness and color, however Khat extract seems harmful to composites’ surfaces.