Microleakage of Gluma Bond, Scotchbond 2 and a glass ionomer/composite sandwich technique

Bonding to dentin with long-term success has been a quest of dentistry for some time. Microleakage is a major problem that can lead to staining and discolorization of the restoration and postoperative sensitivity. Some of the newer dentin bonding systems include Gluma Bond and Scotchbond 2. A glass ionomer/composite "sandwich" technique has also been advocated for dentin bonding. Here a glass ionomer is first bonded to the dentin, bonding agent is applied to the glass ionomer and a composite restoration is then placed into the cavity preparation. The purpose of this study was to compare the microleakage of Gluma Bond, Scotchbond 2, the glass ionomer/composite sandwich technique along with a positive and negative control. This was accomplished, in vitro, using extracted human teeth and a Ca45 radioisotope technique. The teeth were examined for microleakage at periods of 1 week, 6 months and 12 months. The results of this study indicate that, in vitro, the glass ionomer sandwich technique does not stop microleakage. The results also indicate that, in vitro, Gluma Bond and especially Scotchbond 2 restorations can resist microleakage for short periods of time. However, at the end of the 12 months, all Gluma Bond and Scotchbond 2 specimens exhibited gross microleakage.