Dentures are classified into two categories. The first of which are called complete dentures and the second are partial dentures. Complete, or conventional dentures are made in advance and can be positioned as soon as teeth are removed. Thus, the patient does not have to go any time without teeth during their healing period. These dentures will require more refitting, as the healing process changes mouth structure. The second category is partial dentures. These removable dentures or bridge are replacement teeth attached to a gum colored base. These can be used when one or more natural teeth remain in the jaw. A partial denture can fill the space between missing teeth, which keeps any teeth from shifting.