1. A dental appliance system, comprising: a first appliance of a series of appliances designed to incrementally implement a treatment plan, comprising a first shell having a plurality of cavities therein designed to receive teeth of a jaw in a first stage of the treatment plan with at least one of the plurality of cavities being a cavity configured to accommodate virtual maximum dimensions, in three dimensions above the gingival line, of an unerupted or erupting tooth therein; and a second appliance of the series of appliances, comprising a second shell having a plurality of cavities therein designed to receive teeth of the jaw in a second stage of the treatment plan the second shell having a cavity that corresponds with the cavity configured to accommodate virtual maximum dimensions of an unerupted or erupting tooth of the first shell and wherein the virtual maximum dimensions are calculated by taking the maximum dimensions of two or more virtual tooth geometry data sets of the same type of tooth.