Comparison between two procion dyes and alizarin red to assess marginal leakage in resin restorations. A laboratory study.

To assess the width of the gaps that may occur in resin restorations bonded to dentine, buccal and lingual cavities were prepared in 18 caries- and restoration-free extracted molar teeth. All teeth were restored with composite resin. Nine of the teeth were then thermocycled for five hours. All teeth were stained with 0.5 per cent, 1.0 per cent or 1.5 per cent solutions of chloro-s-triazinyl dyes (Reactive Red and Reactive Orange 14) or Alizarin Red in order to assess the effectiveness of each stain in detecting marginal leakage. Quantitative assessment indicated that Reactive Orange 14 was superior to the other two stains as it more clearly defined the marginal gaps of the restorations. This superiority was evident for both thermocycled and nonthermocycled teeth.