FIG. 1 is a side elevation view of the dental appliance; FIG. 2 is a side elevation view of the dental appliance; FIG. 3 is a top plan view of the dental appliance; FIG. 4 is a front elevation view of the dental appliance; FIG. 5 is a bottom plan view of the dental appliance; FIG. 6 is a rear elevation view of the dental appliance; and, FIG. 7 is a cross sectional view of the dental appliance taken along section line 7-7 of FIG. 6.