A conventional over-denture rests over some healthy natural tooth roots. This approach was first reported in 1861. To understand this method, it is necessary to review some facts.
An Overview of Alveolar Ridge Dynamics
- Maintaining a denture on the jawbone ridge (called alveolar ridge) is essential to prevent it from becoming loose during eating, speaking, and other activities.
- Preserving the alveolar ridge facilitates denture stability.
- The body tends to conserve energy and nutrients by maintaining only structures with apparent immediate value. A typical example is the bulk reduction of a broken leg held immobile by a full-leg cast for a month or more.
- The body recognizes that the only one purpose for alveolar bone is to hold tooth roots.
- Alveolar bone no longer supporting a tooth root is removed, or literally dissolved away, by the body. This is called resorption, or simply shrinkage.
- Resorption progresses at varying rates in the same person at different times, and at different rates between different people. Resorption progresses rapidly within the first year of losing a tooth, after which time, the rate progresses at a slower pace.
From this overview, if the maximum amount of alveolar ridge is to be maintained, then preserving the maximum number of periodontally healthy tooth roots should achieve that end.
Preserving the Sensation of Having Teeth
Studies demonstrate that even though only roots are preserved, and a denture covers them, a patient still has sensory input sensations similar to that experienced with teeth, as opposed to individuals with conventional dentures and no preserved roots. Over-denture patients also appear to have a more natural perceived directional sense in their chewing activities. In other words, many patients relate that they still feel like they have teeth -- a positive comment.
Underlying Philosophy of the Conventional Over-Denture
If a patient's treatment plan to have a denture, and the roots of some remaining teeth are supported in healthy alveolar bone, then a conventional over-denture is a viable consideration.
However, only a licensed dentist can determine if a conventional over-denture is a suitable consideration for a certain person, after a comprehensive examination.
Some Characteristics of a Conventional Over-Denture
- Most of a tooth crown (that part of the tooth above the gums) is removed. This often necessitates root canal therapy if not already done.
- The remaining tooth, projecting above the gum, is rounded and usually covered with a similarly shaped artificial crown-like covering.
- Various configurations and extensions may be built onto some retained roots. In those cases, that portion of the denture overlying these configurations is modified to contain attachments that clip onto a framework or receive the individual extensions. In addition to preserving alveolar bone and sensory input, the denture is held securely in place, but may be comfortably and easily removed for cleaning.
Advantages of a Conventional Over-Denture
- Feels more like having teeth
- More retentive in many cases
- Helps reduce shrinkage of surrounding bone
- Reduces pressure to portions of the alveolar ridge
- Positive psychological advantage of still having teeth
Disadvantages of a Conventional Over-Denture
- Scrupulous oral hygiene is essential in order to prevent decay and gum disease
- The over-denture may feel bulkier than a conventional denture
- Frequent maintenance examinations are necessary
- Generally, this is a more expensive approach than a conventional denture
by Joseph J. Massad, D.D.S.
