Evaluation of weight change in three different light cured composite restorative materials stored in water: An in vitro study

The objective of this in vitro study was to investigate whether weight gain in three different composites occurs due to water absorption, when stored in water. The composite restorative materials selected for this study included a micro-fine hybrid (Synergy) and two nano-filled composites (CERAM X duo and FILTEK Z 350). Twenty specimens of each material were fabricated with each composite material.- Group A: Filtek Z 350, Group B: Synergy, and Group C: CERAM X Duo. Then all the specimens were stored in 10 ml distilled water in test tubes, and then placed in an incubator at 37oC for six weeks. The weight changes of these specimens were measured daily for the first week, and, later, once a week, for the next five weeks, by using an electrical analytical balance. The data were analyzed using one-way analysis of variance and Student 't' test. There was a tendency for the weight of the specimens to increase with the passage of time, when stored in water. All the groups showed maximum amount of water absorption in the first week; then there was a gradual decrease in the water absorption, from the second to the sixth week. Synergy showed the maximum amount of water absorption in the first week, as compared to FILTEK Z 350 and Ceram X Duo. However, FILTEK Z 350 showed the maximum amount of water absorption from the second week to the sixth week, as compared to Ceram X Duo and Synergy. All composite restorative materials absorb some amount of water. The water absorption of the composite may decrease the physical and mechanical properties of the composites; hence, it is necessary to consider the type of the material before starting treatment.