Self-etching bonding systems: in-vitro micro-leakage evaluation

The purpose of this in vitro study was to compare dentine and enamel micro-leakage values of six self-etching bonding agents to that of a total etch dentine bonding agent (used as a control). Products evaluated were Scotchbond Multipurpose Plus (3M/ESPE), Xeno III (Dentsply), Clearfil SE Bond (Kuraray), ABF (Kuraray), Optibond Solo Self-Etch (Kerr), OneCoatSE Bond (Colténe Whaledent), and iBond (Heraeus-Kulzer). Using a medium sized Cerana bur (Nordiska Dental) a standard, cylindrical preparation was made at the cemento-enamel junction (CEJ) of human third molars. The teeth were randomly divided into 7 groups of ten teeth each. The bonding agents were applied and light cured strictly according to the manufacturer's instructions and the cavities then filled in two increments, using Z100 composite (3M/ESPE). The restored teeth were imbedded in acrylic resin and thermocycled between 5 degrees - 60 degrees C (+/- 2 degrees C) for 250 cycles with a dwell time of 20 seconds. All seven groups were then placed in a 5% basic Fuchsin solution for 12 hours at 37 degrees C. The embedded teeth were removed from the basic Fuchsin, rinsed well, imbedded in acrylic and cut longitudinally through the centre of each restoration using an Accutom-2 cutting machine. Each tooth was then evaluated at the occlusal enamel margin and at the cervical dentine margin for micro-leakage using a light microscope at 50x magnification. The data obtained was analysed using the Kruskal-Wallis test, with Fisher's least significant difference method used for comparison of specific groups (p<0.05). When compared to the control (Scotchbond Multipurpose Plus), results for microleakage at the occlusal enamel margins as well as the cervical dentine margins indicated that only SE Bond and ABF (Protect Bond) showed values as low as the control. It can be concluded that, as far as micro-leakage is concerned, Clearfil SE Bond and ABF (Protect Bond) self-etching bonding agents could be clinically acceptable alternatives to the clinically proven Scotch-bond Multipurpose. The other products showed more microleakage.