Pre-shaped, non-custom dental trays are either preloaded with bleaching gel or filled with a dental treatment composition just prior to placement over a person's teeth. The pre-shaped dental tray is thin and flexible, which allows it to be placed over a person's teeth and then approximately conform to the person's teeth. The pre-shaped, non-custom dental trays can therefore perform similar to a customized tray but without have to go through the more lengthy customization procedure. The dental treatment composition may comprise one or more of a dental bleaching agent, an anticariogenic agent, an antimicrobial agent, a remineralizing agent, or other active agent. A pre-shaped dental tray can be pre-loaded with a dental treatment composition and stored within a sealed packaging container.