The effect of different storage conditions and duration on the fracture strength of three types of translucent fiber posts

Objectives: (a) To evaluate the effects of storage duration, storage condition and type of fiber post on post fracture strength. (b) To morphologically evaluate the post structure before and after storage. 

Methods: Three types of fiber posts were divided in different groups (n = 14) according to the storage duration (1, 6, 12 months), and storage condition (dry at 37 °C; saline water at 37 °C; mineral oil at 37 °C and storage inside the roots of extracted human teeth immersed in saline water at 37 °C). Specimens were loaded in a universal testing machine with a compressive load until fracture. A 3-way ANOVA and Tukey's test (α = .05) were used to compare the effect of the experimental factors on the fracture strength. Two posts of each group were observed before and after the storage using a scanning electron microscope. 

Results: Storage conditions and post type, had a significant effect on post fracture strength (p < 0.05). The interaction between these factors was significant (p < 0.05). Water storage significantly decreased the fracture strength, regardless of the post type and the storage duration. Storage inside roots, in oil, and at dry conditions did not significantly affect post fracture strength. SEM micrographs revealed voids between fibers and resin matrix for posts stored in water. Posts stored under the other conditions showed a compact matrix without porosities. 

Significance: Fiber posts placed inside human root canals immersed in water are not affected by the detrimental effect of water.