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RESEARCH PRODUCT

Hydrophilic primer has double the risk of bracket bond failure

subject

description

Question: In patients who need orthodontic bracketing is a hydrophilic primer or a conventional primer more effective for bonding? Objective To compare clinical failure rates of brackets bonded with a prototype hydrophilic primer and conventional primer. Design Randomised controlled trial (RCT) in a hospital setting. Intervention A split mouth design was used. Sides were randomly allocated to either hydrophilic (supplied by 3M Unitek (Monrovia, California, USA) or conventional primer (conventional TransbondTM 3M Unitek) adhesive), with the other side having alternative primer. Brackets were applied to 33 patients using a standard procedure. A total of 266 bonds were completed with each primer. Outcome measures Subjects were followed for 6 months and site of failure, type of primer and time since bonding were recorded. Results All 33 patients were seen after 6 months The hydrophilic primer had an increased risk of bracket failure (see Table), with a hazard ratio of 2.2 (95% confidence interval, 1.1–4.5). Conclusions Brackets bonded with the prototype hydrophilic primer had double the risk of failure compared with conventional primer over 6 months. Hydrophilic primer cannot be recommended for clinical use. Littlewood SJ, Mitchell L, Greenwood DC. A randomized controlled trial to investigate brackets bonded with a hydrophilic primer. J Orthod 2001; 28:301–305