A non-custom, dental tray device includes a moisture-resistant barrier layer having a labial-buccal wall, a lingual wall, and a bottom wall. The dental tray device includes at least one of the following structural features to enhance the fit of the device (1) the bottom wall includes an abrupt reduction of width at a location corresponding to where the first bicuspid meets the canine (2) a bottom wall in the posterior region having a width that is equal to or less than the width of the bottom wall in the anterior region, with no lingual wall in the posterior region or (3) a transition portion between the bottom wall and either the labial-buccal wall or the lingual wall has a larger radius of curvature as compared to a radius of curvature at a transition portion between the bottom wall the other of the labial-buccal wall and the lingual wall.
