Examiner agreement in the replacement decision of Class I amalgam restorations

The aim of this study was to investigate interexaminer and intraexaminer agreement in the replacement decision for Class I amalgam restorations. Three examiners evaluated the restorations clinically and with bitewing radiographs. One hundred and twelve restorations were evaluated for secondary caries, body fracture, deficient anatomic form (contour), ditched margins, and marginal overhangs. After one month, the assessments were repeated by the same examiners under the same conditions. Cohen's Kappa analysis was used to analyze the data. The number of replacement decisions varied from 12 to 27 and from 6 to 14 at the first and second evaluations, respectively. The Kappa statistics indicated "moderate" to "substantial" consistency for interexaminer and intraexaminer agreement in the replacement decisions based on clinical and radiographical examinations. Restorations with deficient anatomic form and marginal overhangs presented the most frequent diagnostic difficulties and lead to disagreement among examiners. The most frequently mentioned reasons for replacement were the restorations had ditched margins at both clinical evaluation periods and secondary caries was detected during radiographical evaluations. In the absence of agreement among examiners, clinical and radiographic guidelines are necessary for replacing Class I amalgam restorations.