# Electrochemical properties of dental alloys in various simple solutions simulating saliva

Pascal de March, Patrice Berthod, Carine d'Agostino, Félix Romder

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Pascal de March, Patrice Berthod, Carine d'Agostino, Félix Romder. Electrochemical properties of dental alloys in various simple solutions simulating saliva. Eurocorr 2008, Sep 2008, Edinburgh, United Kingdom. . hal-03864892

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# Electrochemical properties of dental alloys in various simple solutions simulating saliva

Pascal de March, Patrice Berthod, Carine d'Agostino, Félix Romder

<figure><img src="image_3.png" /></figure>

## To cite this version:

Pascal de March, Patrice Berthod, Carine d'Agostino, Félix Romder. Electrochemical properties of dental alloys in various simple solutions simulating saliva. Eurocorr 2008, Sep 2008, Edinburgh, United Kingdom. hal-03864892

HAL Id: hal-03864892

https://hal.archives-ouvertes.fr/hal-03864892

Submitted on 22 Nov 2022

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
# Electrochemical properties of dental alloys in various simple solutions simulating saliva

I Pascal De March¹², Patrice Berthod¹, Carine D'Agostino², Félix Romder¹

1 Laboratoire de Chimie du Solide Minéral (UMR 7555)

Faculté des Sciences et Techniques, Université Henri Poincaré Nancy 1

NancyUniversité, BP 239, F54506 Vandoeuvre les Nancy - France

2 Faculté d'Odontologie de Nancy, Département de Prothèses, 96 avenue de Lattre de Tassigny, BP 50208, 54000 Nancy France

Email: Patrice.Berthod@lcsm.uhnancy.fr

The electrochemical behaviours of eight alloys used for fixed partial denture and their respective postsolder alloys, were specified in solutions of NaCl with various conditions. A follow up of corrosion potential, measurements of the polarization resistance and potentiodynamic experiment, were performed on all alloys. Comparisons were done with data of the Pourbaix's diagram for all the major elements belonging to each studied alloy.

## Fixed partial denture and postsolder joint

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

Different units of fixed partial denture (parent alloy covered by ceramic) are secondary joint by a postsolder joint. This postsolder and a part of parent alloy can be exposed to saliva.

COMPOSITIONS

<table><thead><tr><th>noble alloys</th><th>Au</th><th>Pt</th><th>Pd</th><th>Ga</th><th>In</th><th>others</th></tr></thead><tbody><tr><td>dSIGN98</td><td>86</td><td>12</td><td>/</td><td>/</td><td>/</td><td>2.0 Zn</td></tr><tr><td>Aquarius Hard</td><td>86</td><td>8.5</td><td>2.6</td><td>/</td><td>1.4</td><td></td></tr><tr><td>dSIGN91</td><td>60</td><td>/</td><td>31</td><td>1.0</td><td>8.4</td><td></td></tr><tr><td>Lodestar</td><td>52</td><td>/</td><td>39</td><td>1.5</td><td>8.5</td><td></td></tr><tr><td>W</td><td>54</td><td>/</td><td>26</td><td>/</td><td>1.5</td><td>16 Ag 2.5 Sn</td></tr><tr><td>less noble alloy</td><td>/</td><td>/</td><td>59</td><td>/</td><td>2.7</td><td>28 Ag</td></tr><tr><td>dSIGN59</td><td></td><td></td><td></td><td></td><td></td><td>8.2 Sn-1.3 Zn</td></tr><tr><td>not noble alloys</td><td>Ni</td><td>Cr</td><td>Mo</td><td>W</td><td>Si</td><td>others</td></tr><tr><td>4ALL</td><td>61</td><td>26</td><td>11</td><td>/</td><td>1.5</td><td>/</td></tr><tr><td>Pisces Plus</td><td>62</td><td>22</td><td>/</td><td>11</td><td>2.6</td><td>2.3 Al</td></tr></tbody></table>

<table><thead><tr><th>solder alloys</th><th>Au</th><th>Ag</th><th>Cu</th><th>Ga</th><th>others</th><th>for</th></tr></thead><tbody><tr><td>.650</td><td>65</td><td>13</td><td>20</td><td>2</td><td></td><td>Aquarius Hard</td></tr><tr><td>.615</td><td>61</td><td>13</td><td>17</td><td>/</td><td>7.6 In</td><td>dSIGN91, d59, Lodestar</td></tr><tr><td>.585</td><td>59</td><td>16</td><td>18</td><td>7</td><td>/</td><td>dSIGN98</td></tr><tr><td>LFWG</td><td>56</td><td>27</td><td>/</td><td>/</td><td>16 Zn</td><td>W, Pisces Plus, 4ALL</td></tr></tbody></table>

All alloys and solders were supplied by IVOCLAR VIVADENT

## Experimental Setup

<figure><img src="image_7.png" /></figure>

Working electrode

<figure><img src="image_8.png" /></figure>

Electrochemical cell and the three electrodes.

The studied electrolytes were:

(pH=6.6; 9g/L NaCl)

- (pH=7.4; 9g/L NaCl)

- (pH=7.4; 90g/L NaCl)

All these solutions were prepared from distilled water, pure NaCl and NaOH or HCl for adjustment of pH

Free potential & polarization resistance : example of 4 parent alloys

<table><thead><tr><th rowspan="2">Alloy</th><th rowspan="2">Electrolyte</th><th colspan="4">E<sub>corr</sub> / NHE (mV) at t =</th><th rowspan="2">att = 1h</th><th rowspan="2">att = 2h</th></tr><tr><th>0h</th><th>1h</th><th>2h</th><th>att = 1h</th><th>att = 2h</th></tr></thead><tbody><tr><td rowspan="3">Aquarius Hard</td><td>pH6.6<br>9g/L</td><td>+330</td><td>+350</td><td>+350</td><td>520</td><td>560</td><td></td></tr><tr><td>pH7.4<br>9g/L</td><td>+280</td><td>+370</td><td>+390</td><td>790</td><td>430</td><td></td></tr><tr><td>pH7.4<br>90g/L</td><td>+290</td><td>+300</td><td>+300</td><td>1040</td><td>1440</td><td></td></tr><tr><td rowspan="3">dSIGN91</td><td>pH6.6<br>9g/L</td><td>+250</td><td>+230</td><td>+240</td><td>23</td><td>26</td><td></td></tr><tr><td>pH7.4<br>9g/L</td><td>+210</td><td>+190</td><td>+200</td><td>11</td><td>13</td><td></td></tr><tr><td>pH7.4<br>90g/L</td><td>+240</td><td>+250</td><td>+250</td><td>610</td><td>1190</td><td></td></tr><tr><td rowspan="3">dSIGN59</td><td>pH6.6<br>9g/L</td><td>+40</td><td>+21</td><td>+16</td><td>5</td><td>4</td><td></td></tr><tr><td>pH7.4<br>9g/L</td><td>+41</td><td>+39</td><td>+34</td><td>10</td><td>10</td><td></td></tr><tr><td>pH7.4<br>90g/L</td><td>+470</td><td>+440</td><td>+440</td><td>92</td><td>73</td><td></td></tr><tr><td rowspan="3">Pisces Plus</td><td>pH6.6<br>9g/L</td><td>+110</td><td>+17</td><td>+32</td><td>350</td><td>420</td><td></td></tr><tr><td>pH7.4<br>9g/L</td><td>+74</td><td>+41</td><td>+28</td><td>660</td><td>580</td><td></td></tr><tr><td>pH7.4<br>90g/L</td><td>+130</td><td>+110</td><td>+100</td><td>200</td><td>330</td><td></td></tr></tbody></table>

* For the noblest alloys : E<sub>corr</sub> is high, the noblest elements are in immunity state, others elements in passivated state.

* For the dSIGN 59 : E<sub>corr</sub> is lower, main elements in immunity state or passivated state.

* For the NiCr based Pisces Plus : E<sub>corr</sub> very low, all elements in passivated state

* Polarization resistances are extremely variable but all at very high level

## Examples of potentiodynamic curves obtained in different media

<figure><img src="image_9.png" /></figure>

<figure><img src="image_10.png" /></figure>

* Oxidation of gold, the base element of the noblest alloys, is possible only for very high potentials

* A very high chloride concentration induced an enlargement of the anodic peak toward lower and higher potentials

* The not noble alloys were obviously already passivated when potentiodynamic experiment began

* The postsolder alloys displayed a small anodic peak and a passivation plateau. A possible specific behaviour of copper (for three alloys on four), which seemed fixing the corrosion potential (before potentiodynamic polarisation).

## CONCLUSION

Generally, there was no corrosion for all these alloys, which were in the immunity domains or passivation domains of their constitutive elements.

Nevertheless, corrosion can begin if an especially high anodic potential is applied because of high concentration of strong oxidant species, notably if Cl ions are in high concentration in the same time.