A comparison of the shear strength of chemically versus electrolytically etched metal retainers

The recent popularity of acid-etched, resin-bonded retainers (RBR) has initiated improvements in design, technique, and etching. This study compared the shear strength of chemically etched Biobond retainers with electrolytically etched retainers bonded to enamel using identical cement. Shear fracture loads were recorded using Instrom testing for all specimens. The mean fracture load for the electrolytically etched castings was greater than that of the chemically etched castings. Electrolytically etched specimens also recorded the greatest and the least fracture load values. These results indicated that, while there were significant differences between the two groups with greater shear strength values for electrolytic etching, there was also more variation in shear fracture load with electrolytic etching.