Often, the process of getting beautiful, custom dentures begins with one or more tooth extractions. Next, your dentist will begin the process of creating your new dentures. A conventional denture is fitted after a full-mouth extraction (removal of all teeth) once your gums have healed. In most cases, immediate dentures are created and placed immediately after your extractions, allowing the gums to heal underneath the appliance.
Support is the principle that describes how well the underlying mucosa (oral tissues, including gums) keeps the denture from moving vertically towards the arch in question during chewing, and thus being excessively depressed and moving deeper into the arch. For the mandibular arch, this function is provided primarily by the buccal shelf, a region extending laterally from the back or posterior ridges, and by the pear-shaped pad (the most posterior area of keratinized gingival formed by the scaling down of the retro-molar papilla after the extraction of the last molar tooth). Secondary support for the complete mandibular denture is provided by the alveolar ridge crest. The maxillary arch receives primary support from the horizontal hard palate and the posterior alveolar ridge crest. The larger the denture flanges (that part of the denture that extends into the vestibule), the better the stability (another parameter to assess fit of a complete denture). Long flanges beyond the functional depth of the sulcus are a common error in denture construction, often (but not always) leading to movement in function, and ulcerations (denture sore spots).
Teeth can fall out for a number of reasons, ranging from genetics to drug abuse. Most commonly, teeth are removed or fall out on their own due to severe tooth decay. Neglect to upkeep oral hygiene or not seeking proper treatment for damaged teeth, can lead to the onset of decay which in turn leads to loss of teeth. Visiting you dentist in 6 month intervals is a good preventive measure to spot any early signs of decay.