Zinc-containing high copper amalgams: a 3-year clinical evaluation

Area of Science:

• Dental Materials Science
• Biomaterials Engineering

Background:

• Dental amalgam remains a widely used restorative material.
• High copper amalgams are preferred for improved clinical performance.
• The role of zinc in amalgam properties requires further elucidation.

Purpose of the Study:

• To evaluate the effect of zinc content on the marginal integrity of high copper dental amalgams.
• To compare the clinical serviceability of zinc-containing versus non-zinc amalgam formulations.

Main Methods:

• Five different amalgam formulations were tested: Dispersalloy (0.9% zinc and non-zinc) and Tytin (1.0%, 0.33%, and non-zinc).
• A total of 247 amalgam restorations were randomly placed in 39 patients.
• Restorations were evaluated over a 3-year period.

Main Results:

• Amalgam restorations containing zinc exhibited significantly less marginal fracture compared to those without zinc.
• The beneficial effect of zinc was observed across different formulations and concentrations (approx. 1%).

Conclusions:

• Incorporating small amounts of zinc (around 1%) into high copper dental amalgams enhances their clinical serviceability.
• Zinc appears to play a critical role in preventing marginal fracture in dental amalgam restorations.