Volumetric dimensional change of six direct core materials.
OBJECTIVE
This study evaluated the influence of water on the volumetric dimensional change of six direct placement core build-up materials by using Archimedes' principle.


METHODS
The effect on dimensional change due to the setting reaction was determined through the use of a silicone oil storage medium. The materials used were two dual-cured resin composites (CoreStore and Build-It FR), two chemically activated resin composites (CorePaste and Ti-Core), one metal-reinforced glass ionomer cement (Ketac-Silver), and one resin-modified glass ionomer (Fuji II LC Core). Using the manufacturers' instructions for each material, cylindrical specimens were prepared with dimensions of 7+/-0.1 mm in diameter and 2+/-0.1 mm in height. Each material had four groups (n = 5) based on storage conditions; silicone oil at 23 and 37 degrees C and distilled water at 23 and 37 degrees C. A 0.01 mg resolution balance was used to determine volumetric dimensional change using an Archimedean equation. Measurements were made 30 min after mixing, and at the time intervals of 1, 14, and 56 days.


RESULTS
All materials exhibited dimensional change. Ketac-Silver had the most shrinkage in silicone oil and Fuji II LC showed the highest expansion in distilled water. The glass ionomer materials showed more change than did any of the resin composite materials.


CONCLUSIONS
Current direct placement core materials show variation in the amount of volumetric dimensional change seen over a period of 56 days.
Chutinan
Supattriya
S
Department of Restorative Dentistry, Division of Dental Materials, Indiana University School of Dentistry, 1121 West Michigan Street, Indianapolis, IN 46202, USA.
Platt
Jeffrey A
JA
Cochran
Michael A
MA
Moore
B Keith
BK
D000042:Absorption; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D003442:Crowns; D003890:Desiccation; D004129:Dimethylpolysiloxanes; D005899:Glass Ionomer Cements / Q000737:chemistry*; D012828:Silicones; D018709:Statistics, Nonparametric; D014867:Water
D003188:Composite Resins; D004129:Dimethylpolysiloxanes; D005899:Glass Ionomer Cements; D012828:Silicones; D014867:Water; C013830:baysilon