Direct bonding to typodont teeth

Three methods of bonding orthodontic brackets to acrylic teeth were investigated for use with a typodont. One-hundred-and-twenty Dentaurum 0.018 x 0.025 inch standard Edgewise brackets were bonded to Crylopax cross-linked acrylic teeth using three cements: Concise composite, Concise with acrylic primer, and GAC acrylic cement on a previously roughened tooth surface. Half the specimens in each group was immersed in a thermostatically controlled water bath for 15 min on 20 occasions over a 5-day period, to simulate the conditions of a typodont, prior to measuring tensile bond strength on an Instron machine. Under dry conditions Concise composite was significantly stronger than either Concise with acrylic primer or GAC cold cure acrylic resin. Under wet conditions, however, the mean bond strength of the acrylic resin increased significantly compared to the other cements. The bond strength of both Concise and Concise composite with primer deteriorated following water immersion. It is suggested that when setting up typodont teeth with brackets bonded with GAC acrylic resin, immersion of the bonded teeth in hot water prior to positioning of the teeth in the typodont may greatly reduce the risk of subsequent bracket loss.