C H A P T E R 1 2 S T A B I L I Z A T I O N A P P L I A N C E 179

For the fabrication of this appliance, make impressions of the maxillary and mandibular teeth and an interocclusal record. Once the laboratory has fabricated the maxillary acrylic stabilization appliance, attempt to insert it into the patient ’ s mouth with a moderate amount of force. If the appliance does not seat fully or causes an uncomfortable pressure, then its internal surface needs to be adjusted.

After the appliance seats fully and fi ts comfortably, the mandible is manipulated into the desired position and the appliance ’ s occlusion is adjusted. Using two sheets of black Accufi lm, mark the centric contacts, repeatedly adjusting the marks so at least one centric mark from each posterior tooth and light to no marks from the anterior teeth are obtained. The canine marks may be in harmony with the anterior or posterior marks (Figure 12.26 ).

While adjusting the occlusion, practitioners may fi nd it necessary or more expedient to reline a portion of the occlusal surface. While obtaining the desired centric contacts, periodically ask the patient to close on the appliance and to say whether the left or right side hits fi rst or harder. Adjust the appliance so the patient feels that both sides hit evenly and each side of the appliance has uniform centric marks independent of the other side.

After obtaining the desired centric contacts, adjust the excursive movement. The appliance should allow the patient to easily slide the mandible into the excursive positions, disoccluding the posterior teeth with the closest posterior contact being 1/2 – 1 mm from the appliance. Prior to initiating the excursive movement adjustments, observe the distance the posterior teeth separate as the patient slides the mandible into these positions. This provides an estimate of how much the anterior guidance ramp will need to be adjusted in each direction.

Mark the excursive movements with two sheets of red Accufi lm and ask the patient to

using the same criteria; this generally takes only a few additional adjustments.

Once the appliance ’ s occlusion is adjusted, contour the sides of the appliance. Patients generally appear not to need more than 7 mm for their anterior guidance, so remove any unnecessary portion of the guidance ramp. Most patients also seem to prefer to have the line angles of the occlusal surface rounded and the buccal and lingual occlusogingival curvature similar to the tooth that it covers.

If any portion of the appliance ’ s sides are thicker than 1 mm, consider thinning these areas, especially if the patient plans to wear the appliance during the day. Thinner fl anges make the appliance feel less obtrusive and enable the patient to speak better when wearing the appliance.

Once the appliance is adjusted satisfactorily, ask the patient to insert it. Inform the patient that it will be smoothed further, but that you want to ensure that the posterior teeth hit the appliance as evenly as possible and determine whether the patient knows of anything that can be done to make the appliance more comfortable. Once the appliance meets with the patient ’ s approval, smooth its sides and ask whether it feels satisfactorily smooth.

Maxillary Acrylic Stabilization Appliance

The principles for the maxillary appliance are almost identical to those for the mandibular appliance. There are two prominent differences: (1) the excursive movements are in the opposite directions on the appliance, so the anterior guidance ramp will be lingual to the anterior teeth; and (2) the opposing supporting cusps that provide the appliance ’ s posterior centric contacts are the maxillary lingual cusps for the mandibular appliance, whereas they are the mandibular buccal cusps for the maxillary appliance.