Evaluation of Interactions of Surface Fluorides on Nickel-chromium and Casted Titanium Alloys: An In Vitro Study

The present study was conducted to assess the effects of topical fluoride on casted Titanium and nickel chromium using Scanning Electron Microscope. This in vitro study comprised of 45 specimens of Titanium and 45 specimens of nickel-chromium of same dimensions. They were divided into three groups of 15 each. GroupI specimens were immersed in 2% neutral sodium fluoride (NaF) solution for 16 minutes. Group II specimens were placed in 1.23% acidulated phosphate fluoride (APF) gel for eight minutes. Group III specimens were placed in distilled water for 8 minutes. All specimens were evaluated for surface roughness using a scanning electron microscope. Data thus obtained were subjected to statistical analysis including post-hoc test and analysis variance (ANOVA). There was no significant increase in surface roughness of nickel- chromium specimens in group I, II and III (p > 0.05) whereas Titanium specimens in group II showed a substantial increase in surface roughness (p < 0.05). There was surface corrosion of Titanium specimens and slight pitting of nickel-chromium specimens in group II. The studied preparation (1.23%) of acidulated phosphate fluoride has shown to affect the surface roughness of Titanium and nickel-chromium specimens whereas 2% neutral sodium fluoride and distilled water has no noticeable effect, therefore, providing some logical clinical correlations. Clinicians must be well known about the logical usages of topical fluorides in dentistry. Different fluoride concentrations and preparations are capable of producing prosthesis's surface roughness of various degrees. Surface roughness is acting as potent areas of bacterial adhesion, plaque retention, calculus retention and microcrack formation with poor esthetics and therefore it significantly affect long-term prosthesis success. Thus, the operator must be very critically monitoring and managing the harmful effects of acidic fluoridated on prosthesis made up of casted Titanium and nickel-chromium.