Polymerization shrinkage of different composite resins

Objective: The purpose of this study was to compare the polymerization shrinkage of five composite materials.

Method: The composite resins used in this study were 4 Seasons (Ivoclair/Vivadent), Grandio (Voco), Venus (Heraeus) Amelogen Plus (Ultradent) and P90 (3M ESPE) with A2 Universal or Dentin shades. The polymerization shrinkage was measured calculating the shrinkage percentage using an image measurement device (ACUVOL - Bisco Dental, Schaumburg, IL). The specimens were placed on the pedestal of ACUVOL in equal volume, standardized by a polyurethane matrix with a semi sphere with 3mm of diameter. The specimens were left resting for 5 minutes and then the baseline measure was obtained. After that, 18J of energy were applied on each composite, using a light-curing unit and the shrinkage values were recorded continuously for 10 minutes. The final shrinkage value was calculated by means of percentage of shrinkage.

Result: The application of ANOVA (p=0.05) revealed significant differences among groups. The % Volume Shrinkage (Mean±SD) and results of Tukey test were: 4 Seasons 2.42±0.1^c, Grandio 1.71±0.6^b, Venus 3.09±0.6^d, Amelogen Plus 3.13±0.6^d and P90 1.02±0.6^a. Different letters means significant differences. 

Conclusion: It was concluded that polymerization shrinkage was dependent on the material. P90 (3M ESPE) exhibited the lowest mean values and Venus (Heraeus) and Amelogen Plus (Ultradent) showed the highest percent shrinkage means.