Linear displacement and force induced by polymerization shrinkage of resin-based restorative materials.
OBJECTIVE
To measure the linear displacement and force induced by polymerization shrinkage of a series of resin-based restorative materials.


METHODS
The materials tested were 10 ultrafine midway-filled resin-based composites, mainly used in anterior restorations (Brilliant Dentin, Brilliant Enamel, Charisma F, Pertac II Aplitip, Prodigy, Resulcin, Sculpt-it, Synergy Duo, Tetric and Z100), 11 ultrafine compact-filled composites, suggested by the manufacturers as "amalgam substitutes" for posterior restorations (Alert, Ariston pHc, Definite, EXI-119, EXI-120, Nulite F, Prodigy Condensed, Prodigy High Viscosity, Solotaire, Surefil and Synergy Compact), and six polyacid-modified composites (Compoglass, Dyract, Dyract AP, Elan, F2000 and Hytac Aplitip), also known as compomers. Each property was measured for 180 seconds from the start of curing with the help of custom made devices in eight specimens for each material. Statistical evaluation of the data was performed with one-way ANOVA, Tukey's Studentized Range (HSD) Test (P= 0.05) and simple linear regression.


RESULTS
Statistically significant differences among groups and among composites were found for both of the properties that were studied. The ultrafine compact-filled composites (amalgam substitutes) exhibited the least linear displacement, followed by the polyacid-modified composites (compomers) and the ultrafine midway-filled composites, with statistically significant differences among all groups. The groups followed the same order in the polymerization force, with only the compomer-amalgam substitute comparison not being statistically significantly different. The simple linear regression showed that the two studied properties were also highly correlated (r=0.89).
Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Switzerland. minosstavridakis@yahoo.com
Minos M
MM
Stavridakis
Felix
F
Lutz
William M
WM
Johnston
Ivo
I
Krejci
D000704:Analysis of Variance; D020770:Compomers / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D016014:Linear Models; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry
D020770:Compomers; D003188:Composite Resins; D011108:Polymers