Effect of temperature and humidity on the adhesive strength of orthodontic direct bonding materials

The effects of temperature and humidity on the adhesive strength of two direct bonding orthodontic materials were investigated. Tensile testing showed that the adhesive bond was much stronger than the polycarbonate brackets. There is a significant increase in tensile and shearlike strength after 15-, 22-, and 30-day incubation at 37 C and 100% humidity, as compared with initial strength (after 30 minutes) at room temperature.