6 factors of retention

By Dr.Swathi Pai on Saturday, January 17, 2009 with 0 comments

Retention: the denture’s resistance to removal in the direction opposite of its insertion.

  1. Adhesion: the physical attraction of unlike molecules

  1. Cohesion: the physical attraction between like molecules

  1. Interfacial surface tension: resistance to separation by the film of liquid between the denture base and the supporting tissues (combines cohesion and adhesion).

Mechanical locking into undercuts

  1. Peripheral seal and atmospheric pressure: *the most important factor

  1. Orofacial musculature: correct position of denture teeth must be in the neutral zone

Neutral zone: the area in the mouth where the force of the tongue pressing outward is neutralized by the forces of the cheeks and lips pressing inward. Thus, normal muscle activity will retain the dentures rather than dislodge them.

  1. Stability: the denture’s ability to remain securely in place when it is subjected to horizontal movements. This occurs during the functional force of chewing, talking, singing, whistling, etc.

To be stable, the denture requires the following (5):

-good retention
-non-interfering occlusion
-proper tooth arrangement
-proper form and contour of the polished surfaces
-good control and coordination of the patient’s musculature

The soft tissue along the junction of the hard and soft palate on which pressure can be applied by a denture to aid in retention.

Category: Prosthodontics Notes



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