To evaluate the clinical performance of a plasma arc light (Ortho LITE, 3M Unitek, Monrovia, CA, USA) against a conventional tungsten-quartz halogen curing light (Visilux 2, 3M Unitek, Monrovia, CA, USA) for direct orthodontic bonding. A single centre prospective randomized controlled clinical trial. The Orthodontic Department at St Luke's Hospital, Bradford, UK. Forty-three consecutive patients requiring fixed appliances from the orthodontic waiting list. A split mouth technique was adopted; with quadrants randomly assigned to either the plasma arc light or the conventional halogen curing light and bonded directly with APC pre-adjusted edgewise brackets (3M Unitek, Monrovia, CA, USA). Bracket failures. Time taken to bond-up the appliances, patient sensitivity or discomfort during curing and time to replace failed brackets were investigated. No statistically significant difference in bracket failure rates over the full course of treatment was found between the plasma arc light (6.7%; 95% CI 4.5-10.0) and the halogen curing light (9.5%; 95% CI 6.8-13.1). There was no statistically significant difference in bracket survival times. The bond-up times were typically reduced by 204 seconds per patient with the plasma arc light. There were no differences in patient reported sensitivity or discomfort or rebond times. The plasma arc light is a viable clinical alternative to the conventional halogen curing light with benefits for both the clinician and patient due to reduced bonding times.