Complete dentures can be either "conventional" or "immediate." A conventional denture is usually made after all the teeth in the upper or lower arch are removed . The area is allowed to heal for about a period of 8 to 12 weeks. after that a conventional denture is custom made to the tissue and healed gums. This process provides a very accurate fit than an immediate denture, but it take approximately 4 to 5 visits to fit and custom fabricate the conventional denture. The down side to a conventional denture is that the patient has to wait his gum and tissues have healed before their permanent dentures are completed.
Unlike conventional dentures, immediate dentures are made in advance and can be positioned as soon as the teeth are removed. As a result, the wearer does not have to be without teeth during the healing period. However, bones and gums shrink over time, especially during the healing period following tooth removal. Therefore a disadvantage of immediate dentures compared with conventional dentures is that they require more adjustments to fit properly during the healing process and generally should only be considered a temporary solution until conventional dentures can be made.
A removable partial denture or bridge usually consists of replacement teeth attached to a pink or gum-colored plastic base, which is sometimes connected by metal framework that holds the denture in place in the mouth (http://www.webmd.com/oral-health/ss/slideshow-mouth-problems). Partial dentures can now be made with very durable plastic frames. Partial dentures are used when one or more natural teeth remain in the upper or lower jaw. Not only does a partial denture fill in the spaces created by missing teeth, it prevents other teeth from changing position. Unlike a fixed partial denture, a removable is usually very difficult to get used to.
An overdenture is a denture that is designed with connections to dental implants. The implants provide the denture stability, as a result the fit, function and use is much better. The more implants placed, the more stable the denture. It is possible to fabricate an upper denture with an open palate if a minimum of 4 implants are placed. This will provide more comfort to patients that gage easily and allow them to taste and feel the food better.