Assessment of Effect of Fluoride on Titanium Dental Implants.

Background: Titanium has always been the material of choice for dental implants. The present study was conducted to assess effect of fluoride on titanium dental implants. Materials and
Methods: Forty samples of pure titanium and Ti-6Al-4V were tested in an electrochemical cell.
Results: Ecorr/V of titanium implant in artificial saliva was -0.42, and in artificial saliva, +0.25% NaF was -0.63. Ecorr/V of Ti-6Al-4V in artificial saliva was -0.56 and in artificial saliva +0.25% NaF was -0.60.
Conclusion: There was significant effect of fluoride on titanium implants in terms of corrosion. Copyright:

INTRODUCTION

Titanium has always been the material of choice for dental implants. It was found to be the only biomaterial to osseointegrate and was assumed to have bioactive properties due to the formation of a hydrated oxide layer which could incorporate calcium and phosphorous.[1] The high stability of titanium is created thanks to the formation of the titanium oxide (TiO2) layer, which forms on the outer aspect of the implant.[2]

Corrosion, the graded degradation of materials by electrochemical attack is of concern, particularly when a metallic implant, metallic filling, or orthodontic appliances are placed in the hostile electrolytic environment provided by the human mouth.[3] Fluoride may contribute to the corrosion of dental implants. Fluoride has been used in dental hygiene products for many years. It is predominately used in the prevention of dental caries. Dentists will prescribe higher dosages for those who are at a higher risk of the disease.[4] The present study was conducted to assess effect of fluoride on titanium dental implants.

MATERIALS AND METHODS

The present in vitro study comprised 40 titanium dental implants. Samples of pure titanium and Ti–6Al–4V tested in an electrochemical cell. The medium used was artificial saliva and the combination of artificial saliva and 0.25% NaF. Data were extracted and polarization curves were plotted allowing corrosion potential. Ecorr and current density, j corr was measured. Results were assessed statistically.

RESULTS

Table 1 shows that Ecorr/V of titanium implant in artificial saliva was −0.42, and in artificial saliva, +0.25% NaF was −0.63. Ecorr/V of Ti–6Al–4V in artificial saliva was −0.56 and in artificial saliva +0.25% NaF was −0.60. The difference was significant (P < 0.05).

Table 1

Assessment of Ecorr/V

Implant	Artificial saliva	Artificial saliva + 0.25% NaF	P
Ti	−0.42	−0.63	0.01
Ti-6Al-4V	−0.56	−0.60	0.09

Table 2 shows that the mean j corr/V of titanium implant in artificial saliva was 5.2 × 10−8, and in artificial saliva +0.25% NaF was 1.3 × 10−8. Ti–6Al–4V was 1.4 × 10−7 in artificial saliva and 4.1 × 10−6 in artificial saliva + 0.25% NaF. The difference was significant (P < 0.05).

Table 2

Assessment of j corr/V

Implant	Artificial saliva	Artificial saliva + 0.25% NaF	P
Ti	5.2×10−8	1.3×10−8	0.01
Ti-6Al-4V	1.4×10−7	4.1×10−6	0.09

DISCUSSION

Titanium was considered due to its lightness and good mechanochemical properties. The stability of the implant can, however, be compromised if the TiO2 layer is lost and cannot reform. This then makes titanium as unstable as any other metal. Biomaterial surface chemistry, topography (roughness), and type of tissue integration correlate with host response. Biocompatibility of the implants and its associated structure is important for proper function of the prosthesis in the mouth.[5] Corrosion can severely limit the fatigue life and ultimate strength of the material leading to mechanical failure of the dental materials. High noble alloys used in dentistry are so stable chemically that they do not undergo significant corrosion in the oral environment. The major component of these alloys is gold, palladium, and platinum.[6] The present study was conducted to assess effect of fluoride on titanium dental implants.

We found that Ecorr/V of titanium implant in artificial saliva was −0.42, and in artificial saliva, +0.25% NaF was −0.63. Ecorr/V of Ti–6Al–4V in artificial saliva was −0.56 and in artificial saliva +0.25% NaF was −0.60. We observed that the mean j corr/V of titanium implant in artificial saliva was 5.2 × 10−8, and in artificial saliva, + 0.25% NaF was 1.3 × 10−8. Ti–6Al–4V was 1.4 × 10−7 in artificial saliva and 4.1 × 10−6 in artificial saliva +0.25% NaF. Fraser[7] analyzed the available literature to identify whether fluoride causes corrosion of titanium or Ti–6Al–4V, two materials commonly used to construct dental implants. Of the five studies included in this mini-systematic review, all concluded that fluoride does cause corrosion of dental implants, particularly in the presence of an acidic pH.

CONCLUSION

The authors found that there was significant effect of fluoride on titanium implants in terms of corrosion.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.