Objectives. This study was designed to develop a methodology that woul
d measure the monomer conversion of dental restorative resins without
the use of an infrared spectrometer. Methods. Specimens were prepared
from heat-cured TEGDMA/MMA copolymers consisting of 0,20,40,60, 80 and
100 mole% TEGDMA. The pre- and post-cure volumes of bar-shaped specim
ens (45 x 7 x 1 mm) and thin films were measured. The cure of the thin
specimens was determined using changes in resin volume as well as by
an infrared spectroscopic method. The cure of thin specimens of a comm
ercially available unfilled bonding resin was also determined using th
e shrinkage method and by conventional infrared spectroscopic methods.
Results. There was no difference (p = 0.0617) between cure values of
the commercial resin using either conventional IR methods or the shrin
kage methods. For each copolymer combination of thin films, there was
also no significant difference in the extent of cure between the IR me
thod used and the shrinkage method presented (lowest p-value 0.29). Th
e cure of TEGDMA/MMA copolymer bar specimens demonstrated a decreasing
trend of cure with increasing proportion of TEGDMA, and had cure valu
es which were similar to others reported in the literature. Significan
ce. The evidence from this study demonstrated that the specimen volume
method can be used to determine the extent of resin cure of thin film
or bulk resin specimens. This method represents an easily performed p
rocedure that can be used by all investigators without expensive equip
ment.