[Corrosion of titanium in presence of dental amalgams and fluorides].
OBJECTIVE
The aim of this study was to evaluate the behaviour of titanium (Ti) in precipitant condition, and more precisely the resistance against corrosion of Ti in presence of fluorides and the electrochemical interaction between Ti- amalgam couples in fluorinated solution.


METHODS
The experimental test was made with the use of an electrochemical cell. The following materials were tested: commercially pure Ti and 2 types of amalgams, the Persistalloy (Prs) and the IQC. Palladium (IQC.P). The free corrosion potential of Ti and the amalgams, the polarization curves of both amalgams and the corrosion current of the Ti-amalgam couples in the measurements were performed in 3 different electrolytic solutions: Ringer solution, fluorinated neutral Ringer solution and acid fluorinated solution. The three corrosive media are described.


RESULTS
The results showed that Ti could be damaged by the presence of fluorides with an acid pH: Ti potential becomes more negative in acid fluorinated solution. The corrosion currents between Ti and amalgam couples were considered: the amalgams underwent anodic oxidation in neutral Ringer, but a reversal phenomenon occurred in the fluorinated acid solution: Ti was damaged and the amalgams both Prs and IQC.P became the cathodic partner of the couple. In neutral fluorinated solution the IQC.P amalgam induced a significantly higher corrosion of Ti, when compared to the Prs one.


CONCLUSIONS
Results clearly show the dependence of the Ti corrosion behaviour on the pH and composition of the solution and that the outcome of the damage is affected by the composition of other metals.
Di Carlo
F
F
Reparto di Protesi Dentaria, Istituto di Clinica Odontoiatrica, Università degli Studi di Roma La Sapienza, Rome, Italy.
Cassinelli
C
C
Morra
M
M
Ronconi
L F
LF
Andreasi Bassi
M
M
De Muro
G
G
Quaranta
A
A
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003343:Corrosion; D003723:Dental Amalgam / Q000494:pharmacology*; D005459:Fluorides / Q000494:pharmacology*; D014025:Titanium
D003723:Dental Amalgam; D014025:Titanium; D005459:Fluorides