Glass ionomer cements used as bonding materials for metal orthodontic brackets. An in vitro study.

The forces required to debond orthodontic brackets on human teeth were studied in vitro. The brackets were bonded with different glass ionomer cements (GICs), and a composite resin (Concise). The shear force required to remove the brackets was recorded at different time intervals after bonding. The bond strength was considerably lower for the GICs compared with brackets bonded with the composite resin, at all time intervals that were studied. Moreover, the bond strength increased more slowly for the GICs compared with the resin. Different GICs displayed a varying setting time. The bonding strength of GICs increased more than 50 per cent between 10 and 20 minutes setting time.