Full Dentures

Full dentures are usually made of acrylic and rely entirely on a close fit and suction to hold them in place. (Since there are no standing teeth left in the mouth, there can be no clasps to help retention). The close fit and the surface profile in contact with surrounding muscles produce a degree of suction, which is much more effective on the upper arch than the lower. Hence lower dentures tend to be less stable than uppers.

The larger the alveolar ridges (bone) the better will be the retention. When teeth are first extracted the ridge that is left is often quite prominent, but with time it gradually shrinks and can after several years become virtually flat. Ill fitting dentures will cause a more rapid absorption and flattening of the bony ridge. In these cases, even the best made dentures will have poor retention or poor stability.