Water sorption of three types of composite resins

Abstract

Silorane low shrink composite resin material introduced with a non-methacrylate
resin matrix to realize a fundamental improvement in cure shrinkage, clinical and
physical properties. The aim of this study is to measure the water sorption of three
type of composite material: Filtek P90, Filtek P60, IPS Empress composites after
immersion in deionized distilled water as a function of time.
Thirty disk shape plastic molds (4 mm diameter and 2mm thickness) were
constructed to form composite blocks. Teen blocks were made from Filtek P 90
(Silorane) GI, Filtek P 60 (packable) GII and IPS Empress (Nanohybrid) GIII. All
specimens were placed in a silica-gel desiccator for 48 hours. The samples were then
weighed three times using calibrated electronic microbalance and the average reading
was recorded to the nearest 0. 0001g then specimens were kept in individual
containers in deionized distilled water at 37 oC. All specimens were periodically
weighed. The weight measurements were taken from the second day after incubation
and continue as one measurement every week for 6 weeks. Data were subjected to
statistical analysis using descriptive analysis, ANOVA and least significant
differences LSD test.
Statistical analysis of the results showed that all the specimens continued to gain
weight for a period of 4 weeks. After that period the weight gain continued, although
at reduced rate. Filtek P90 (Silorane) GI has highly significant less water sorption
value ( p < 0.01) than the other groups after 6 weeks, while there was no significant
differences ( p > 0.٠٥) between IPS Empress (Nanohybrid ) GIII and Filtek P60 (
Packable ) GII in their water sorption value with higher value for GIII.
Silorane which based on siloxane and oxirane resin matrix has less value after 6
weeks followed by Packable composite while IPS Empress has higher value for water
sorption. This study concluded that the differences in water sorption capacity of the
three composite resin materials are related to the differences in the type of resin
matrix, the amount of filler loading and filler particle size.