When the number and location of the teeth remaining in the mouth are not sufficient for a permanent/fixed restoration and implants are not an option for whatever the reason, then the conventional solution is partial (appliances) or complete dentures. These are either held in place by the remaining teeth (appliances) or secured by natural suction, ensuring adequate support, retainment and functionality. The aesthetic result and comfort of these removable restorations is perfectly satisfactory in most cases following an adjustment period. The disadvantages are their (relative) volume, their removable nature and, in some cases, their retainment. However, their real advantage lies in the cost.
Crowns are caps that are placed over a tooth to cover and protect it from breaking, when it is weak or when it has some cosmetic problem that cannot be corrected using a more conservative method. More than one crown together may complete or bridge missing teeth, in which case, they are called fixed bridges. These are cemented onto natural teeth and aesthetically or functionally are no different from them. Crowns and bridges are made of a variety of materials, depending on the cosmetic, strength and cost requirements. They vary from simple metal acrylic crowns, to metal ceramic (porcelain-fused-to-metal) and finally to all-ceramic restorations, without metal frameworks (emax, in ceram, zirconia, etc.). The disadvantages are tooth surface grinding, as well as the cost.