Film thickness and fluidity of various luting cements determined using a trial indentation meter.
OBJECTIVE
The purpose of this study was to evaluate a new trial apparatus which could measure film thickness (T(h)) under a low load, using an indenter.


METHODS
Five commercial luting cements were measured using this apparatus. T(h) was determined using four kinds of indenter, which were 5.0, 10.0, 15.0 and 20.0mm in diameter. For each indenter, the load per contact area of the indenter with the platen equaled 150N per 200 mm2 described in ISO No. 9917. The effects of working time (30, 60, and 90 s) and load (2.86, 6.78, 10.7, and 14.7N) on the fluidity and T(h) were examined using the indenter with a diameter of 5.0mm. The duration of loading was 10 min. The fluidity was defined as the reciprocal of the apparent viscosity and was calculated using Stefan's equation.


RESULTS
The T(h) obtained using this apparatus agreed with the film thickness obtained using the test described in ISO No. 9917. For Durelon (DU), T(h) increased 1.58 times and fluidity decreased 0.26 times as the working time increased from 30 to 90 s; T(h) decreased 0.56 times and fluidity increased 1.28 times as loading increased from 2.86 to 14.7N. For Ketac cement radiopaque (KE), Panavia fluoro cement (PA), Scotchbond resin cement (SC), and Vitremer luting cement (VI), although the fluidity and T(h) were not influenced much by duration (30-90 s), T(h) decreased 0.79, 0.74, 0.95, and 0.78 times for KE, PA, SC, and VI, respectively, and fluidity decreased 0.68, 0.51, 0.30, and 0.36 times, respectively, as loading increased from 2.86 to 14.7N.


CONCLUSIONS
This apparatus was proven effective in elucidating the flow properties of luting cement.
Tsukada
Gakuji
G
Department of Restorative Dentistry and Endodontology, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan. tsukada@dentb.hal.kagoshima-u.ac.jp
Tanaka
Toshiaki
T
Kajihara
Takeshi
T
Torii
Mitsuo
M
Inoue
Katsuichiro
K
D003188:Composite Resins / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D004867:Equipment Design; D005899:Glass Ionomer Cements / Q000737:chemistry; D006244:Hardness; D006801:Humans; D008422:Materials Testing / Q000295:instrumentation; D011076:Polycarboxylate Cement / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014783:Viscosity
D003188:Composite Resins; D003738:Dental Cements; D005899:Glass Ionomer Cements; C438843:Panavia-Fluoro; D011076:Polycarboxylate Cement; D019279:Resin Cements; C084550:Vitremer; C078532:Ketac Cem Radiopaque; C031374:zinc polyacrylate; C041330:Scotchbond