REPAIR DURABILITY OF A WATER-AGED MICROFINE HYBRID RESTORATIVE RESIN COMPOSITE: A NANO-LEAKAGE STUDY

Abstract

Aim: To evaluate the effect of using two types of flowable resin composites and storage time on nano-leakage of repaired water aged resin composite. Materials and Methods: In total, 30 resin composite discs were prepared and stored in distilled water for 6 m. The discs were then randomly divided into 6 experimental groups (n=5/group) according to the two experimental factors of the study: Factor 1: Flowable composite, 3 groups (no-flowable, high-viscosity and low-viscosity flowable composites), and Factor 2; Storage time after repair, 2 groups (24 h and 6 m). Repair procedures were carried out using universal adhesive with and without the application of the flowable composite. After repair, half of the specimens were stored for 24 h and the other half were stored for 6 m in distilled water. After the recommended storage time, each disc was sectioned into 2 halves and each half was prepared for silver nitrate staining procedures to evaluate the nano-leakage under SEM. Three photomicrographs were taken for each half-slab, resulting in 30 photomicrographs/group, which were analyzed using ImageJ software. Data were evaluated using Kruskal-Wallis/Mann-Whitney test (P=0.05). Results: The use of flowable composite had no significant effect on nano-leakage (P=0.129), while storage time showed a statistically significant effect on nano-leakage (P < 0.0001). There was no statistically significant difference regarding the use of flowable resin composite either at 24 h or 6 m storage times (P > 0.05). There was a statistically significant difference between 24 h and 6 m storage periods for all experimental variables (P < 0.05). Conclusion: The two types of flowable composites were not able to prevent the uptake of silver nitrate at the composite/composite interface either after 24 h or 6 m.