Management of Class I and Class II Amalgam Restorations with Localized Defects: Five-Year Results

Replacement of dental restorations has been the traditional treatment for defective restorations. This five-year prospective clinical trial evaluated amalgam restorations with localized defects that were treated by means of repair or refurbishing. Fifty-two patients (50% female and 50% male, mean age years, range 18–80) with 160 class I and class II defective restorations were included. The study focused on the application of two minimally invasive treatments for localized restoration defects and compared these with no treatment and total replacement as negative and positive controls, respectively. Restorations were assessed by two calibrated examiners according to modified U.S. Public Health Service criteria, including marginal adaptation, anatomic form, secondary caries, and roughness. At five years, recall was examined in 45 patients with 108 restorations (67.5%). The results suggest that repair treatment is as effective as total replacement of restorations with localized defects, reducing biological costs to the patient and providing new tools to the clinician. Refinishing restoration is a useful treatment for localized anatomic form defects. 1. Introduction Amalgam is a restorative material especially suitable for classes I and II restorations in teeth that encounter heavy chewing forces. The advantages of amalgam restorations include resistance to wear, tolerance to a wide range of clinical placement conditions, and excellent load-bearing properties [1–3]. However, amalgam restorations may also present degradation in the intraoral environment due to secondary caries, fracture, marginal breakdown, and wear [4–6]. The traditional solution for those failures has been the complete replacement of the restorations, which may also include minor imperfections in the restorations, and replacement of defective restorations represents a major concern in dental practice, reaching up to 60% of operative dentistry interventions [7]. Consequently, the median survival time (MST) of amalgam varies from 2 to 11 years, but most studies place it at over 5 years [8–10]. Complete replacement of restorations has the disadvantages of being time consuming, unnecessary removal of healthy tooth tissue, enlarging preparations and restoration sizes [11, 12], the risk of converting the restoration to an indirect restoration, and the possibility of major injuries in pulp tissues [12–14]. During the last years, new strategies, such as repair and refinishing of localized defects, have shown improvement in the quality of the defective restorations and increased longevity of