Debonding Stresses of Metal Orthodontic Brackets Retained to Tooth Enamel with Co-Cured Self-Etch Primer

Abstract

Background: Applying the recently suggested resin primer co-curing technique could save some of patients’ and orthodontists’ time. This study evaluated the efficiency of self-etch primer co-curing protocol in retaining orthodontic brackets. Methods: A self-etch orthodontic resin primer was pre-cured or co-cured together with the resin adhesive (Groups 1 and 2) to retain either non-coated or pre-coated orthodontic brackets (Subgroups 1 and 2) on the buccal surfaces of extracted premolars. The debonding stress values were evaluated immediately after bonding (category 1) and after exposure to cyclic intraoral hydraulic, thermal, and mechanical stress simulations (Category 2). The adhesive remanent index (ARI) was also assessed for each test category. Results: The co-cured primer provided higher immediate debonding stress values of both non- and pre-coated brackets (Tukey’s, P<0.05) than did the pre-cured primer. The delayed debonding stress values were lower than the immediately assessed values (Tukey’s, P<0.05) for both types of brackets. No difference (Mann Whitney’s, P>0.05) was noticed in the ARIs of all test categories. Conclusions: Although the intraoral stress simulations reduce the brackets’ debonding stress values, co-curing the self-etch orthodontic primer can offer clinically efficient bonding of both non- and pre-coated metal brackets with no harm to the tooth enamel on debonding.