As it is taught in as taught in Spear’s occlusion workshop, partial coverage appliances like NTIs and anterior bite planes can be wonderful appliances when it comes to decreasing muscle activity. However, they do have some significant downsides and limitations. First of all, small appliances like the NTI have a choking risk if they become loose while the patients is sleeping; this is one of the reasons why a larger appliance is taught at Spear. Partial coverage appliances, no matter how they are designed, carry a risk of intrusion and/or super-eruption with them.
This potential for tooth movement is the reason we recommend limiting the wear of an appliance to eight hours or less a day. The trouble comes when we – or our patients – want or need to wear the appliance for more than eight hours a day. In this article, I’d like to discuss a solution that will help decrease the risks associated with longer wear of a deprogrammer that we teach in the workshop.
Key step to increasing wear time of an anterior appliance
Obviously, the first step is to fabricate a full arch anterior deprogrammer. For those of you that have not taken this workshop, this is a full arch essix-like shell made out of 1.5mm Biocryl with a flat bite place from canine to canine. (Figure 1)
The next step is to make the lower component that allows for the increased wear time. To do this, you need to form a piece of Isofolan over the lower model first like you do for the maxillary bite plane. (Figure 2)
The next step is to place composite over the lower central incisors in the shape of a small mound, creating a stylus. (Figure 3)
The next step is to form a sheet of 1.5mm Biocryl over the model. The last and final step is to trim and polish the lower appliance which should leave you with an appliance like you see in the final photo. (Figure 4) Now, when the patient wears the two appliances at the same time all of their teeth are covered, which results in a greatly decreased risk of any intrusion or super-eruption. Another side benefit of fabricating the lower stylus is that you essentially eliminate any need for adjustments when you deliver the appliance.
John R. Carson, DDS, PC, Spear Visiting Faculty and Contributing Author www.johncarsondds.com