In-vitro bond strengths and clinical failure rates of metal brackets bonded with different light-emitting diode units and curing times

Introduction The purpose of this study was to compare the clinical failure rates and the in-vitro bond strengths of metal brackets bonded with different light-emitting diode (LED) devices and curing times. Methods Forty patients were included in the clinical part of this study. A split-mouth design was used, with the adhesive in group 1 cured for 10 seconds with an LED unit (Elipar S10; 3M Unitek, Monrovia, Calif), and the adhesive in group 2 cured for 3 seconds with another LED unit (VALO Ortho; Ultradent Products, South Jordan, Utah). Bond failures during 12 months of orthodontic treatment were recorded. In-vitro performance of the brackets was also compared by bonding brackets to extracted premolars and using the same light units and curing times (n = 20 for each group). The adhesive remnant index was used to determine the bond failure interface. Results Clinical bond failure rates were 2.90% for the Elipar and 3.16% for the VALO curing units. The difference in bracket failure rates between the 2 LED devices was not statistically significant. No statistically significant difference was found between the in-vitro bond strengths of the groups. Conclusions Our findings regarding long-term clinical survival rates and in-vitro bond strengths indicate that bracket bonding can be safely accomplished in 10 seconds of light-curing with an Elipar LED and 3 seconds of light-curing with a VALO LED.