Clinical performance of orthodontic brackets and adhesive systems: a randomized clinical trial

The aim of the study was to evaluate and compare the clinical performance of adhesive precoated brackets (APC) with that of two types of uncoated bracket bases, Straight-Wire and Dyna-Lock, bonded using two types of orthodontic adhesives, Transbond XT, and Right-On. Forty consecutive orthodontic patients entered the trial and 607 brackets were bonded. The incidence and site of first time bond failures were recorded over a period of 1 year. The time required for bonding was also recorded. The overall bond failure rate was 6.6 per cent. There were no significant differences between the failure rates of the five groups, or between the upper and lower arch. However, significantly more brackets failed on the left side than on the right. Premolar brackets were lost most often, whilst incisor brackets failed least. No association was found between bond failure and time elapsed since bonding. Bonding time was least with Right-On adhesive. There were no significant differences between bonding times using APC or Transbond. Results of the present study conflict with those of a previous ex vivo study by the authors, using the same materials and bonding technique. Suggested reasons for this are discussed.