Finishing of amalgam restorations: a three-year clinical study

Class I and Class II amalgam restorations were placed in the permanent teeth of 66 patients, each of whom received a minimum of three restorations. At least one of these restorations was carved-only, at least one was immediately finished (using a prophylaxis paste on rubber cups at low speed, 8 or 10 min after trituration), and at least one restoration was polished (using finishing burs and polishing points, more than 24 h after placement). The number of restorations available for assessment of marginal fracture using the 11-unit photographic scale developed by Mahler was 253 at baseline, 249 at 1-year and 2-year recalls and 228 at the 3-year recall. Although polished restorations exhibited greater initial (baseline) marginal fracture, at 1-year, 2-year and 3-year recalls the restorations were found to exhibit a similar amount of marginal fracture regardless of the finishing technique. The amount of perceived marginal fracture increased steadily after 1 year. The immediate finishing of amalgam restorations showed no long-term benefit over the other techniques and has little to commend it. The clinical finishing of amalgam restorations is discussed in the light of this and other research.