Clinical evaluation of a fluoride-exchanging resin as an orthodontic adhesive.

The purpose of this study is to examine the clinical durability and caries inhibition potential of a fluoride-exchanging resin (FER) when used as an orthodontic bracket-bonding adhesive. In the clinical durability investigation, orthodontic brackets were bonded to alternate teeth with the FER in 10 patients scheduled for routine orthodontic procedures. The remaining teeth were bonded with Concise orthodontic resin. Number of bonding failures and the site and mode (adhesive or cohesive) of failure were recorded. Also included in the study were 10 patients scheduled for orthodontic care with prescribed extraction of four first premolars. Bracketed teeth were extracted after 60 days and were sectioned and examined with polarized light microscopy using H2O and quinoline as imbibition media. Failure rates for the FER and Concise were 10.8% and 7.3%, respectively. Occurrence of adhesive rather than cohesive, failure indicates that structural integrity was maintained for both adhesives. Microscopic examination of specimens with H2O showed lesion formation to be 2.78% for the FER and 1.73% for Concise. These lesions were large and not seen in positions near the brackets indicating presence before bonding. With quinoline, dark zone formation was 2.3% for the FER and 33.5% for Concise, indicating a 93% reduction in the first stages of enamel alteration. Results demonstrate that the fluoride-exchanging resin holds promise as a practical caries-preventive adhesive.