This study assessed the in vivo bond failure rates of orthodontic brackets bonded using Orthosolo universal bond enhancer and compared it with the conventional bonding primer, Transbond XT. This was a single centre randomized controlled clinical study. Department of Child Dental Health, Bristol Dental Hospital, Bristol, UK. Thirty-three consecutive patients undergoing fixed orthodontic appliance therapy were included in this study. Using a split-mouth design, diagonally opposite quadrants were randomly allocated a primer, either Orthosolo universal bond enhancer (Ormco, Orange, CA, USA) or Transbond XT primer (3M Unitek, Monrovia, CA, USA). A total of 555 teeth were bonded using a conventional acid-etch technique. 277 received Orthosolo as their primer and 278 received the Transbond XT primer. Bond failures and their positions were recorded at six months. There was an overall bond failure rate of 1.26%. Four brackets failed in the Orthosolo group (0.72%) and three failed in the Transbond XT group (0.54%). There was no clinical or statistically significant difference in the in vivo bond failure rates between orthodontic brackets bonded using either Orthosolo universal bond enhancer or the conventional Transbond XT primer.