Electrochemical behaviour of titanium in ammine and stannous fluoride and chlorhexidine 0.2 percent mouthwashes.

Titanium (Ti) is widely used in dentistry. Fluorides at acid pH could destabilize Ti oxide and make it susceptible to corrosion. The behaviour of IV grade machined Ti disks in 5 electrolytic solutions: Fusayama artificial saliva (Fas), ammine fluoride-stannous fluoride (Am-SnF2), 0.2 percent Chlorexidine (CHX) 0.20 percent, Fas with 20 percent Am-SnF2, and Fas with 20 percent CHX, was evaluated. Open circuit potential Ecorr was determined by immersing Ti disks for 24 hours in an electrochemical cell containing the solutions, potential changes were measured until a stable value was obtained. Examination by Scanning Electronic Microscope and Energy Dispersive X-ray Analysis were then performed. One way ANOVA analysis showed a significant difference of Ecorr values regarding the 5 solutions (p less than 0.001). The highest values were observed for Fas (-37.6 mV), intermediate for Am-SnF2 (-81mV) and lowest for CHX (-87.6mV). SEM analysis of disks after polarization curve in CHX showed a marked localized corrosion, while the other solutions showed no considerable corrosive action on Ti surface. When considering corrosive potential range in oral cavity, Ti had an excellent behaviour on both antiseptics evaluated. The results obtained in this study will enable us to recommend the use of Am-SnF2 mouthwash for patients with dental implants.

Influence of amine fluoride/stannous fluoride mouthwashes with and without chlorhexidine on secretion of proinflammatory molecules by peri-implant crevicular fluid cells.

AIM: Patients with dental implants need optimal plaque control. Peri-implantitis is an inflammation of soft and hard tissues around implants characterized by bone loss mediated by proinflammatory molecules such as IL-1beta, PGE(2), vascular endothelial growth factor (VEGF). The aim of this study was to evaluate the influence of amine fluoride/stannous fluoride (AmF-SnF(2)) vs chlorhexidine 0.12% (CHX) combined with Am-SnF(2) on IL-1beta, PGE(2) and EGF secretion by cells of crevicular peri-implant fluid. METHODS: Thirty patients with dental implants were included in this study. The test group used AmF-SnF(2) rinsing for 14 days, the control group used CHX rinsing during the first 7 days and AmF-SnF(2) during the following 7 days. Crevicular samples were collected using filter paper strips and assayed for level of IL-1beta, PGE(2) and VEGF with ELISA test. Data were analyzed with paired and unpaired t test. RESULTS: IL-1beta, VEGF and PGE(2) levels were significantly lower in test compared to control group. Comparing first with second week of treatment, a greater decrease of IL-1beta and VEGF was evident in sample group during the second week. There was a lower decrease of IL-1beta and VEGF during the entire treatment in control group. Differences of PGE(2) levels after 7 days in both the groups were not significant while there was a significant difference during the second week. CONCLUSION: The following data suggest that the use of AmF-SnF(2) could decrease the production of IL-1beta, PGE(2) and VEGF by inflammatory cells.AmF-SnF(2) could be an alternative to CHX mouth rinses in plaque control of patients with implants.

[Corrosion of titanium in presence of dental amalgams and fluorides]. / La corrosione del titanio in presenza di amalgami e fluoruri.

AIM: 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. CONCLUSION: 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.