The effectiveness of four-cavity treatment systems in sealing amalgam restorations

Amalgam does not bond to tooth tissue; therefore, restorations using such material are prone to leakage despite the deposition of corrosion products. This study evaluated the effectiveness of four cavity treatment systems placed in vivo in sealing restorations of amalgam. Four cavity treatment systems were investigated in this study: Cervitec, Gluma One Bond, Panavia 21 and Copaliner Dentin Varnish and Sealant. No cavity treatment was placed in an additional group to serve as a control. The teeth were extracted within 15 minutes of restoration placement. The specimens were thermocycled (5-55 +/- 2 degrees C, 500 cycles), immersed in a dye solution, sectioned and scored for leakage. Scanning electron microscopy also examined features of the tooth/restoration interfaces. There were statistically significant differences among the groups regarding leakage scores (p = 0.00). None of the materials tested consistently prevented leakage; however, use of Copaliner Dentin Varnish and Sealant resulted in less overall, occlusal and cervical microleakage than any other systems tested. Significantly more leakage was observed in relation to the cervical portions of the cavities (p = 0.00). No significant differences were identified between the leakage scores obtained for the buccal and palatal (lingual) cavities and the different tooth types (p = 0.52 and 0.83, respectively). A level of significance of 0.05 was selected in all cases. The benefits of the materials tested in this study need to be evaluated using robust, long-term clinical studies. Further work should continue to develop laboratory tests that predict the behavior and performance of cavity sealants in clinical service.