Tricks of the trade: debonding loops for bonded acrylic expanders

Rapid maxillary expansion (RME) provides a means of expanding the upper arch by separation at the midline palatal suture. One approach to this expansion is to use a bonded acrylic variant. As the name implies, this adheres to the teeth by means of a glass ionomer or resin cement. The abundant tooth surface area under the acrylic pads, in addition to the potential for cement to flow into any undercuts, results in the bonded expander being very well retained. This is beneficial until it comes time to remove the appliance, when the tenacity of the bond may be a source of potential discomfort for the patient and frustration for the clinician.

Removal of bonded acrylic expanders can be greatly facilitated through the incorporation of specially designed debonding loops developed by David Sarver. The method is as follows.

One loop, made of 0.036-inch stainless steel wire, is placed on each side. Each loop crosses the occlusal surfaces at the embrasure and touches the occlusal surface of the teeth in the mesial and distal fossae of the second premolar (Figure 1). During construction, each loop should be secured with wax to contact the model in the fossae but with 1-mm clearance elsewhere. The clearance allows acrylic to flow under the wire and aids the loop's incorporation into the appliance. Blocking out 1 mm buccally creates space for the beaks of Weingart pliers to grasp the loop when it is time to remove the appliance (Figure 2).