Talk:Galvanic pain

Confusing opening sentence

I find this opening sentence somewhat ambiguous:

Galvanic Pain is an unusual type of dental pain caused by an electrochemical circuit between contacting dental restorations of dissimilar metal alloys and saliva.[2]

Is "contacting dental restoration" a term of art, or is "contacting" an adjective modifying either the dissimilar metal alloys or the alloys and the saliva? Also, "dissimilar metal alloys" could refer to alloys of dissimilar metals, presumably, or two alloys made of dissimilar metals.

I'm not 100% certain that I'm understanding the situation correctly, here, so here's how I understand it: Two adjacent teeth have fillings with dissimilar metals in them, which come in contact with one another, creating an electrochemical half-cell. These teeth are sitting in a pool of saliva, which acts as a salt bridge and completes the circuit, causing current to flow until the redox reaction is complete. If that is the case, here is a suggested rewording of the opening sentence that alleviates these ambiguities:

Galvanic pain is an unusual type of dental pain caused by an electrochemical circuit formed when adjacent dental restorations made of dissimilar metals come into contact in the presence of saliva.

I feel like there's still something that can be done with the "made of dissimilar metals" to further clarify things, but it's not really coming to me at the moment. I think that "made of dissimilar metal alloys" might be an acceptable and more accurate phrasing, if the "made of dissimilar ..." wording is to be kept. 0x0077BE [^talk/_contrib] 16:22, 13 February 2014 (UTC)

I think writing this out convinced me that this change is good, so I went ahead and changed it. 0x0077BE [^talk/_contrib] 16:51, 13 February 2014 (UTC)

"Contacting dental restoration"-- meaning 2 dental restorations (e.g. filling, crown, etc) which are in contact (e.g. during biting).

"Dissimilar metal alloys"-- I think they have to contain different metals. This is reported as occurring between dental amalgam (containing silver, mercury, tin, copper) and gold alloys. I don't think this would occur between 2 different alloys of gold, or 2 amalgam fillings which had slightly different composition.

To further improve clarity, could have:

“ Galvanic pain is an unusual type of dental pain caused by an electrochemical circuit formed when adjacent dental restorations made of dissimilar metal alloys (e.g. amalgam and gold)[1] come into contact in the presence of saliva.[2] ”

Thanks for looking over this article, and apologies for the confusing wording. I don't understand the science behind this well, just replicating what the sources were saying, but they were slightly contradictory. Lesion (talk) 18:20, 13 February 2014 (UTC)

No problem, it's a very interesting phenomenon! I think your wording with the added examples of dissimilar metal alloys is an improvement. I also didn't consider that the contact might occur between teeth only during biting; maybe we need to remove "adjacent", as I'm not sure that two restorations are considered "adjacent" if one is on the upper row and the other is on the lower row. 0x0077BE [^talk/_contrib] 19:24, 13 February 2014 (UTC)

Yes it is bizarre... I've never seen it. OK I will add that tweak to the lead. Adjacent generally means alongside, and opposing generally means the tooth that bites into it on the other arch (i.e. the upper left third molar is adjacent to the upper left second molar, and the lower left third molar opposes the the upper left third molar ... if that makes sense). Lesion (talk) 20:00, 13 February 2014 (UTC)

Galvanic corrosion

@Lesion: - Responding to your latest edit description - I think that the galvanic corrosion only happens when the metals are in contact. There may be other forms corrosion occurring due to the saliva, but the galvanic corrosion specifically is occurring during the current flow as the electrochemical potentials of the two metals can balance out. I'm fairly sure it doesn't happen when the two are simply immersed in a common electrolyte bath. 0x0077BE [^talk/_contrib] 22:58, 14 February 2014 (UTC)

Re-read the sources and Soratur 2002 seems to exactly agree with you. Galvanic corrosion only takes place during direct contact, although saliva is also required, presumably a coating of saliva on either surface which then acts as a medium when the surfaces are brought into apposition. Thanks, it is good to be accurate. Lesion (talk) 23:43, 14 February 2014 (UTC)