Learn About Conventional Over-Denture
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.
+Jim Du Molin is a leading Internet search expert helping individuals and families connect with the right dentist in their area. Visit his author page.
When Should a Denture Be Replaced?
There is no specifically agreed-upon chronological answer by dentists to "When should a denture be replaced?" There are instances where dentures have been replaced after 1 year or less, and on the opposite side of the spectrum, there are people who have worn the same dentures for 25 or more years. These ranges obviously are extremes.
However, on average, dentists seem to be replacing dentures somewhere between four to eight years. This would seem to imply that the average denture fabricated from contemporary biomaterials will wear out and deteriorate within that time and/or the average denture patient's jaws have changed so much that a new denture must be redone.
Each individual's denture needs are different. There are some factors that a licensed dentist takes into consideration when evaluating the need to replace dentures.
Denture Longevity Considerations
Lost vertical dimension:
The proper linear distance relationship between the upper and lower jaws is called vertical dimension. This is unique for each individual.
As one's jaw changes and the ridges upon which dentures rest shrink, a denture becomes loose and vertical dimension begins to change (the vertical dimension is said to be lost by a certain linear measurement unit such as millimeters). Additional plastic (acrylic resin) is added to the inside of a loosening denture (called relining a denture) to stabilize it by reducing looseness caused from jaw shrinkage. However, relining does not restore vertical dimension in an accurate way.
The current position held by most dentists is that when vertical dimension has been lost by three millimeters or more, a new denture should be fabricated in order to restore vertical dimension and maintain functional health.
There are individuals who have worn the same denture for extended periods with considerable loss of vertical dimension over time. Since vertical dimension loss is a slow, but nevertheless progressive, process, they have gradually adapted to a continually increasing closed bite position. These individuals often have a sunken facial appearance and usually appear much older than their chronological age.
Functioning with an abnormal vertical dimension may eventually result in alterations of the temporomandibular joints (TMJ, the jaw joint located in front of the ears). This can lead to significant pain and difficulty with effective eating and even the jaw motions involved with speech. It frequently becomes quite difficult, if not impossible, to restore such individual's proper vertical dimension and chewing efficiency by relining and repairing this older denture.
Tooth wear:
Aside from impaired ability to chew effectively, excess tooth wear will adversely affect esthetics and cause other problems associated with lost vertical dimension, as described above. While porcelain denture teeth will wear at a slower rate than plastic teeth, they nevertheless will wear and are more susceptible to chipping and cracking. Multiple cracked teeth will need to be replaced.
Deterioration: While the biomaterials used by dentists to fabricate dentures today are quite durable, they still deteriorate and exhibit dimensional change over time -- no longer fitting properly, even after relining.
Aging plastic looses its natural appearance and texture, and coloration fades, making dentures look quite artificial.
Deteriorating plastic also makes it easier for dentures to become excessively contaminated with microorganisms. This contributes to mouth irritation and bad taste, and socially unacceptable odors will develop that no amount of denture cleaning will seem to eliminate.
Keeping regular dental check-ups with your dentist so that one's dentures, soft tissues, and jawbone may be checked is essential to extending the life of a denture and maintaining oral health.
by Joseph J. Massad, D.D.S.
+Jim Du Molin is a leading Internet search expert helping individuals and families connect with the right dentist in their area. Visit his author page.