Compomers--a new bracket bonding generation in orthodontics?

Compomers are a new class of materials. With the compomer Dyract Ortho., specifically for bracket bonding, and with Prime & Bond 2.0, a one-component primer for enamel and dentin, DeTrey/Dentsply has developed alternative new materials. The aim of this in vitro study was to test the tensile bonding strength of these materials with different kinds of brackets. Twelve test groups, each with 30 prepared bovine incisors, were formed. Two primers, Prime & Bond 2.0 and PSA, were used. 50% of all teeth were first etched will 36% phosphoric acid. Three types of brackets--metal, ceramic and silan ceramic--were bonded with the compomer Dyract Ortho. For 90 teeth forming a control group, the composite Concise was used. When conditioning the enamel with 36% phosphoric acid, the compomer Dyract Ortho showed a similar tensile bonding strength to the composite Concise. This was not the case if metal brackets were used. Metal brackets had significantly less tensile bonding strength (p < 0.001). The interface of the compomer with the bracket was the main failure site. There was insufficient retention between the compomer and the foil mesh of the bracket base because of the strong consistency of the compomer. Without enamel etching, Dyract Ortho produced an acceptable result only in combination with the primer Prime & Bond 2.0 and silan ceramic brackets. As insufficient data are available to date, the use of compomers in clinical practice cannot yet be recommended.