Clinically, Dispersalloy (Dentsply) restorations containing Zn, in occlusal contact with gold restorations occasionally elicit galvanic pain. This pain is reduced when the restoration is polished with tin oxide immediately after carving or treated with 2% silver nitrate.

Objectives: This study presents laboratory data supporting surface treatment modalities and identifying the influence of Zn and time in oral galvanic pain.

Methods: The galvanic currents between a Type III cast gold (JRVT, Jensen) and Dispersalloy (Zn) amalgams of different surface conditions were measured by the zero-resistance-ammeter technique in a synthetic saliva solution for 10 hrs. Different conditions included: 1) as carved, 2) carved - 24 hrs delay, 3) carved plus tin oxide, 4) carved plus silver nitrate. In addition, the galvanic currents between the same gold and 5) Tytin non-zinc (Kerr), 6) Tytin experimental (Zn), and 7) Dispersalloy experimental (non-Zn) were also measured in their as carved condition. The gold/amalgam area ratio was 2. The current-time curve for each amalgam was integrated to yield anodic charge density (C-Coulombs/cm2). Triplicate tests were performed for each measurement.

Results: The C values (Mean ± S.D.) for different couples tested are: 1) 24.88 ± 3.04 E, 2) 2.32 ± 0.48 A, 3) 13.52 ± 2.48 C, 4) 12.88 ± 2.56 C, 5) 12.40 ± 1.20 C, 6) 20.32 ± 1.36 D, 7) 6.88 ± 1.04 B. The means with different letters are significantly different (p<.05).

Conclusions: Galvanic interaction between cast gold and amalgam is reduced with time and surface treatments of tin oxide and silver nitrate, but increased considerably when the amalgam contains Zn.

Back to the Dental Materials: VII - Others-Metallic Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)

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