Comparison of residual monomer amounts released from indirect bonding adhesives

Abstract

ABSTRACT Objectives To quantify the amount of residual monomer released from orthodontic adhesives used in the indirect bonding technique and compare it to a direct bonding composite resin. Materials and Methods Five hundred stainless steel orthodontic brackets were bonded on bovine incisors using five groups of bonding resins: Transbond XT (TXT), Transbond Supreme LV (SLV), Sondhi Rapid-Set (SRS), Transbond IDB (IDB), and Custom I.Q. (CIQ). Liquid samples were gathered on the first, seventh, 21st, and 35th days. Residual monomer release was measured from the liquid samples with a liquid chromatography device. In addition, the amount and shape of the adhesive between the tooth surface and the bracket base was evaluated using obtained electron microscopy images. The data were analyzed using analysis of variance, and a Tukey post-hoc test was applied. Results Hydroxyethylmethacrylate and bisphenol A-glycidyl methacrylate monomers were released by all study groups. Urethane-dimethacrylate was released from the TXT, SLV, IDB, and CIQ groups. Triethylene glycol dimethacrylate was released from TXT, SLV, IDB, and SRS groups. The amount of total monomer release was higher in chemically cured adhesives than in light-cured adhesives. Among the chemically cured adhesives, premix adhesives had the highest amount of total monomer release. The light-cured adhesives had less thickness. Conclusions Light-curing adhesives have significantly less monomer release than chemically polymerized adhesives.