Walker Richard S, Wade A Gardiner, Iazzetti Gelsomina, Sarkar Nikhil K
Department of Operative Dentistry and Biomaterials, Louisiana State University School of Dentistry, New Orleans 70119, USA.
J Am Dent Assoc. 2003 Nov;134(11):1463-7. doi: 10.14219/jada.archive.2003.0075.
Previous studies have investigated the electrolytic action of oral electrogalvanism. However, the reasons why certain treatments or materials are successful in reducing galvanic current have not been addressed fully. This study assessed galvanic current with several materials, surface conditions and treatments.
The authors measured galvanic currents between a type 3 cast gold alloy and Dispersalloy Dispersed Phase Alloy (zinc) (Dentsply Caulk, Milford, Del.) under different surface conditions using a zero-resistance-ammeter technique in a synthetic saliva solution for 10 hours. In addition, the galvanic currents between the same gold and Tytin alloy (non-zinc) (Kerr, Orange, Calif.), experimental zinc alloy (same makeup as that of Tytin, with the addition of zinc) and non-zinc dispersed-phase experimental alloy (essentially the same physical and chemical makeup as that of Dispersalloy, with the exclusion of zinc) were measured. Triplicate tests were performed for each condition.
The statistical analysis indicated that electrogalvanic activity is reduced significantly when the amalgam surface is treated with tin oxide or silver nitrate. Both zinc-containing amalgams in their as-carved condition exhibited higher anodic charge densities than did their zinc-free counterparts. Galvanic current measured in Dispersalloy was reduced with the passage of time after carving.
Galvanic interaction between cast gold and amalgam is reduced with time and surface treatments, but is increased considerably when the amalgam contains zinc.
Amalgam restorations containing zinc that are in contact with gold restorations occasionally elicit galvanic pain. Selection of a non-zinc-containing amalgam will reduce the level of galvanic interaction. Galvanic pain from occlusal contact is reduced or eliminated when the restoration is brushed with tin oxide immediately after carving or is treated with 2 percent silver nitrate. Some patients may benefit from having their teeth separated with nonconducting rubber dam material.
以往的研究已经探讨了口腔电偶作用的电解效应。然而，某些治疗方法或材料成功降低电流的原因尚未得到充分研究。本研究评估了几种材料、表面状况和治疗方法下的电流。
作者使用零电阻电流表技术，在合成唾液溶液中，于不同表面状况下，测量3型铸造金合金与Dispersalloy分散相合金（锌）（登士柏考克公司，米尔福德，特拉华州）之间的电流，持续10小时。此外，还测量了相同金合金与Tytin合金（非锌）（克尔公司，奥兰治，加利福尼亚州）、实验性锌合金（与Tytin合金成分相同，但添加了锌）以及非锌分散相实验合金（基本上与Dispersalloy合金具有相同的物理和化学组成，但不含锌）之间的电流。每种情况均进行三次重复测试。
统计分析表明，当汞合金表面用氧化锡或硝酸银处理时，电偶活性显著降低。两种含锌汞合金在初雕刻状态下的阳极电荷密度均高于不含锌的对应物。雕刻后，Dispersalloy合金中测量到的电流随时间推移而降低。
铸造金与汞合金之间的电偶相互作用随时间和表面处理而降低，但当汞合金含锌时会显著增加。
与金修复体接触的含锌汞合金修复体偶尔会引发电偶性疼痛。选择不含锌的汞合金将降低电偶相互作用水平。雕刻后立即用氧化锡刷牙或用2%硝酸银处理修复体，可减少或消除因咬合接触引起的电偶性疼痛。一些患者使用非导电橡胶障材料分隔牙齿可能会受益。
