The finishing and early marginal fracture of clinical amalgam restorations.

One operator placed 249 Tytin amalgam restorations in Class I and II preparations in the permanent teeth of 60 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 (at 8 or 10 min after trituration), and at least one restoration was polished (more than 24 h after placement). Restorations were principally assessed for marginal fracture at baseline and 1 year using the 11-unit scale for the evaluation of photographs developed by Mahler. Five factors were also assessed clinically at 1 year. Amalgam restorations, polished using finishing burs and rubber points at least 24 h after placement, exhibited more initial marginal fracture than carved-only or immediately finished restorations. At 1 year, the three techniques were comparable except for the superior surface texture of the polished restorations. The technique of immediate finishing of amalgam restorations has nothing to commend it in preference to existing techniques.