A dental appliance for treating bruxism, sleep apena, or a combination thereof is disclosed. The appliance may include upper and lower portions. The upper portion may engage the upper teeth of a patient and comprise a first anterior feature comprising an indentation having a deepest point and an arcuate groove. The lower portion may engage the lower teeth of the patient and comprise a second anterior feature comprising a protrusion. As the patient bites down, the protrusion may contact or slide within the indentation at a point of contact that is a sole or initial contact between the upper and lower portions. Thus, the interaction of the protrusion and concave surface may control certain mandibular loadings and motions of the patient.
