Long-term cytotoxicity of dental casting alloys.
OBJECTIVE
Current in vitro cytotoxicity tests for dental casting alloys may be inadequate because they use a short-term test (generally < 168 h) for a material that is present in the mouth for years. A modified in vitro test was used to test the cytotoxicity of 8 dental casting alloys and 3 pure metals. This modified test attempted to simulate the long-term effects of dental casting alloys in the mouth.


METHODS
Alloys were tested in cell culture either immediately after polishing (initial) or after 10 months of conditioning in a biologic medium containing serum proteins. The cytotoxicities of the 2 conditions were then compared. Alloys were repolished to assess the reversibility of the 10-month conditioning.


RESULTS
Alloys with little initial cytotoxicity showed no 10-month cytotoxicity. Alloys with significant initial toxicity showed significantly less toxicity at 10 months. No alloy increased in toxicity after conditioning. Repolishing multiple times did not necessarily reestablish the initial cytotoxicity response.


CONCLUSIONS
The results indicate that short-term cytotoxicity tests may not accurately measure the long-term cytotoxicity of these types of alloys.
Wataha
J C
JC
Department of Oral Rehabilitation, Medical College of Georgia School of Dentistry, Augusta 30912-1260, USA. watahaj@mail.mcg.edu
Lockwood
P E
PE
Nelson
S K
SK
Bouillaguet
S
S
D016475:3T3 Cells / Q000187:drug effects; D000704:Analysis of Variance; D000818:Animals; D017077:Culture Media, Conditioned; D003722:Dental Alloys / Q000633:toxicity*; D003735:Dental Casting Technique; D003775:Dental Polishing; D008137:Longitudinal Studies; D051379:Mice; D008807:Mice, Inbred BALB C; D013997:Time Factors; D018675:Toxicity Tests
D017077:Culture Media, Conditioned; D003722:Dental Alloys