Curing shrinkage and volumetric changes of resin-modified glass ionomer restorative materials.
OBJECTIVE
The objective of the study was to evaluate initial curing shrinkage and volumetric change during water storage of six resin-modified glass ionomer cements (Dyract, DeTrey Dentsply; Fuji II LC, GC Dental Int.; Ionosit Fil, DMG; VariGlass VLC, DeTrey Dentsply; Vitremer, 3M Dental Products; Photac-Fil, ESPE), a hybrid composite (blend-a-lux, Blendax) and a chemical-cured glass ionomer cement (ChemFil Superior, DeTrey Dentsply).


METHODS
The curing shrinkage was determined 5 min and 24 h after polymerization and mixing, respectively. Volumetric changes were examined after 14 d and 28 d water storage. Curing shrinkage and volumetric changes were evaluated using the hydrostatic principle. In addition, the total water content of the materials was measured after 28 d water storage.


RESULTS
Curing shrinkage of most of the resin-modified glass ionomers was greater than the hybrid composite and the chemical-cured glass ionomer cement. After a 28 d water storage, the resin-modified glass ionomers showed volumetric expansion and the chemical-cured glass ionomer showed volumetric loss. All of the examined glass ionomer materials had a higher total water content than the composite. SIGNIFICANCE. The large curing shrinkage of the resin-modified glass ionomer materials measured in this in vitro study could affect the marginal integrity of glass ionomer restorations.
Attin
T
T
Department of Operative Dentistry, University Clinic of Dentistry, Freiburg, Germany.
Buchalla
W
W
Kielbassa
A M
AM
Helwig
E
E
D000180:Acrylic Resins / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D000704:Analysis of Variance; D020770:Compomers; D003188:Composite Resins / Q000737:chemistry*; D004356:Drug Storage; D005899:Glass Ionomer Cements / Q000737:chemistry*; D008027:Light; D008689:Methacrylates / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D014867:Water
D000180:Acrylic Resins; D000538:Aluminum Silicates; D020770:Compomers; D003188:Composite Resins; C088486:Dyract; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; C091836:Ionosit; D008689:Methacrylates; C081144:Photac-Fil; D012117:Resins, Synthetic; D017640:Silicates; C081982:VariGlass VLC; C084550:Vitremer; D014867:Water; C039733:Chemfil