[Effect of graphite and phosphate investments on the biological characteristics of pure titanium castings].
OBJECTIVE
To investigate the effect of surface structural changes caused by graphite and phosphate investments on the biological characteristics of pure titanium castings.


METHODS
Round casting pads of pure titanium were processed by graphite and phosphate investments respectively, then grouped into four. With the control of guta purca of the same size, Ultraviolet spectrometry was used to test the cytotoxicity of samples via the ISO, GB and Shanghai biomaterial research and testing center's standards. Mucous irritation test was performed on hamsters' pouch.


RESULTS
Titanium castings obtained from both investment materials have reached the national standard of cytotoxicity and mucous irritation test no matter they have been undergone surface treatment or not.


CONCLUSIONS
Both investment materials cause no obvious changes on biological characteristics of pure titanium castings with the existing of surface structural changes.
Yan
Q M
QM
School of Stomatology, The Affiliated Ninth Hospital of Shanghai Second Medical University, Shanghai 200011, China. qiaomeiyan@yahoo.com
Zhang
J Z
JZ