Failure rates among metal brackets cured with two high-intensity LED light-curing lamps: an in vivo study

Objective: The objective of this split-mouth clinical trial was to compare bonding failure rates of metal brackets bonded with two different light-emitting diode (LED) light-curing lamps with different high-intensity power outputs. Materials and methods: Forty patients were included for a total of 800 brackets that were randomly bonded (left and right sides in a 1:1 ratio) in maxillary and mandibular arches using two different LED devices. An LED of 3200 mW/cm(2) and an LED of 5000 mW/cm(2) were used in this split-mouth clinical trial. Bonding failures during the initial 6 months of orthodontic treatment were recorded as maxillary versus mandibular, anterior teeth versus posterior teeth, and left side versus right side. Results: Five dropouts were recorded for discontinuing orthodontic treatment and 700 brackets were analysed in total.The bonding failure rates for 3200 and 5000 mW/cm(2) LEDs were 6.0 and 7.4 per cent, respectively (P= 0.450), which were not statistically significantly different. There were no significant differences in bracket survival rates between the LEDs used (P = 0.866). The posterior teeth presented a higher index of bond failures (odds ratio, 3.14; 95% confidence interval, 1.68-5.87; P< 0.001). Limitations: Direct comparison was only done between two high-intensity LED lights rather than against conventionally used halogen lights. Conclusion: Similar bonding failures were recorded using both LED devices (3200 and 5000 mW/cm(2)). Significantly more bonding failures occurred in premolar teeth than in anterior teeth.