Film thickness and flow properties of resin-based cements at different temperatures.
BACKGROUND
For a luting agent to allow complete seating of prosthetic restorations, it must obtain an appropriate flow rate maintaining a minimum film thickness. The performance of recently introduced luting agents in this regard has not been evaluated.


OBJECTIVE
To measure and compare the film thickness and flow properties of seven resin-containing luting cements at different temperatures (37°C, 25°C and10°C).


METHODS
Specimens were prepared from five resin luting cements; seT (SDI), Panavia F (Kuraray), Varioloink II (Ivoclar), Maxcem (Kerr), Nexus2 (Kerr) and two resin-modified glass-ionomer luting cements (RM-GICs); GC Fuji Plus (GC Corporation), and RelyX Luting 2 (3 M/ESPE). The film thickness and flow rate of each cement (n=15) was determined using the test described in ISO at three different temperatures.


RESULTS
There was a linear correlation between film thickness and flow rate for most of the materials. Cooling increased fluidity of almost all materials while the effect of temperature on film thickness was material dependent. At 37°C, all products revealed a film thickness of less than 25µm except for GC Fuji Plus. At 25°C, all cements produced a film thickness of less than 27 µm except for seT. At 10°C, apart from seT and Rely X Luting 2, the remaining cements showed a film thickness smaller than 20 µm.


CONCLUSIONS
Cooling increased fluidity of almost all materials, however. the film thickness did not exceed 35 µm in either condition, in spite of the lowest film thickness being demonstrated at the lowest temperature.
Dept. of Dental Materials and Biomaterial Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
R
R
Bagheri
Film Thickness; Flow; Resin Cements