Effect of temperature variation on the cytotoxicity of cast dental alloys and commercially pure titanium.
Cell culture system has been used to evaluate alloy cytotoxicity under different environments, testing the extracts, but the effect of temperature variation on the cytotoxicity of dental alloys has not been analyzed.


OBJECTIVE
The aim of the present study was to investigate if temperature variation could affect dental alloy cytotoxicity, testing alloy extracts in an epithelial cell culture system.


METHODS
Discs of Ni-Cr, Co-Cr-Mo, Ni-Cr-Ti, Ti-6Al-4V and commercially pure titanium (cp Ti) were cast by arc melting, under argon atmosphere, injected by vacuum-pressure. Discs were immersed in artificial saliva and subjected to different temperatures: 37 degrees C and thermocycling (37 degrees C/5 degrees C/37 degrees C/55 degrees C/37 degrees C). After thermocycling, extracts were put in a subconfluent culture during 6 h, and the number of cells and their viability were used to evaluate cytotoxicity in these temperatures. For each alloy, data from temperature conditions were compared by Student's t-test (alpha=0.05).


RESULTS
The cytotoxicity tests with alloy/metal extracts showed that Ni-Cr, Co-Cr-Mo, Ti-6Al-4V and cp Ti extracts (p>0.05) did not affect cell number or cell viability, while Ni-Cr-Ti (p<0.05) extract decreased cell number and viability when the alloy was subjected to thermocycling.


CONCLUSIONS
Within the limitations of the present study, the Ni-Cr-Ti alloy had cell number and viability decreased when subjected to temperature variation, while the other alloys/metal extracts did not show these results.
Faria
Adriana Cláudia Lapria
AC
Department of Dental Materials and Prosthodontics, Ribeirão Preto Dental School, University of São Paulo, Ribeirão Preto, SP, Brazil.
Rodrigues
Renata Cristina Silveira
RC
Antunes
Rossana Pereira de Almeida
RP
de Mattos
Maria da Gloria Chiarello
Mda G
Rosa
Adalberto Luiz
AL
Ribeiro
Ricardo Faria
RF
D000497:Alloys / Q000737:chemistry / Q000633:toxicity; D000537:Aluminum Oxide / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry / Q000633:toxicity; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D002452:Cell Count; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002858:Chromium Alloys / Q000737:chemistry / Q000633:toxicity; D003722:Dental Alloys / Q000737:chemistry / Q000633:toxicity*; D003734:Dental Casting Investment / Q000737:chemistry / Q000633:toxicity*; D003735:Dental Casting Technique; D045662:Dental Etching; D003764:Dental Materials / Q000737:chemistry / Q000633:toxicity*; D003775:Dental Polishing / Q000379:methods; D018130:Diamond / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D012464:Saliva, Artificial / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*
D000497:Alloys; D001672:Biocompatible Materials; D017554:Carbon Compounds, Inorganic; D002858:Chromium Alloys; D003722:Dental Alloys; D003734:Dental Casting Investment; D003764:Dental Materials; D012464:Saliva, Artificial; D017655:Silicon Compounds; C031462:titanium alloy (TiAl6V4); C013616:nitinol; D012822:Silicon Dioxide; D018130:Diamond; D014025:Titanium; D000537:Aluminum Oxide; C022088:silicon carbide