Ta. Bean et al., COMPARISON OF TETRAZOLIUM COLORIMETRIC AND CR-51 RELEASE ASSAYS FOR CYTOTOXICITY DETERMINATION OF DENTAL BIOMATERIALS, Dental materials, 11(5-6), 1995, pp. 327-331
Objectives. The purpose of this study was to compare a methylthiazole
tetrazolium (MTT) dye colorimeiric method with the standard Cr-51 assa
y as methods of assessing cytotoxicity of denial materials. Methods. T
wo MTT-based colorimetric formals, test tube and 96-well microplate me
thods, were compared to the Cr-51 release assay. A series of eight den
tal materials were evaluated. Cytotoxicity profiles were determined fo
r each test material. A TC50 value (Toxic Concentration required to ki
ll 50% of the cells) was determined for each biomaterial, and these re
sults were used to make statistical comparisons between the methods. R
esults. The three methods were statistically correlated (p < 0.005) by
comparison of the eight samples tested. That is, the same rank in tox
icity was given by the two tetrazolium sample formats and the Cr-51 me
thod. Significance. The MTT assay was found to have several advantages
in comparison to the current standard Cr-51 release assay. Optimized
in the 96 well format, complete dose response curves and greater sampl
e comparisons can be made rapidly, making the MTT method more economic
al in time and cost. Furthermore, the MTT method is based on intracell
ular biochemical changes, measuring cell viability rather than cell mo
rbidity, and has lower detectable limits than the Cr-51 release method
. There is also less detector chemical binding interference than encou
ntered in the Cr-51 release method.