Frena

These move with the muscles of the lips, cheeks and tongue during speech, mastication and all activity. The peripheries of the dentures must be designed to allow for these movements, but such allowance must not be excessive otherwise the peripheral seal will be broken. The correct and incorrect method of allowing for Frena developed frena, or those which are attached too high on the alveolar ridge, may be removed surgically. In mouths exhibiting very poor retention, the removal of all the frena increases the peripheral seal.