Removable Dentures - in Your Local Area

Are Lower Dentures Always A Problem?

While dentures are marginally adequate substitutes for missing natural teeth, the lower denture can be troublesome for many individuals.

Inherent Lower Denture Problems

• A lower denture interfaces with more movable mouth surfaces than an upper denture.
• The lower denture has less stabilizing surface to rest upon. For example, there is no broad palatal surface (roof of the mouth) as in an upper denture.
• Loss of jawbone over time brings a lower denture into closer contact with tissue extensions called frenum attachments, which create dislodging forces.

While these problems are inherent to lower dentures, every person is different and not affected in the same way. There are ways to approach these problems.

Some Considerations for Improving Lower Denture Stability

A thin band-like tissue extension (called a frenum) may attach between a jaw ridge (called an alveolar ridge) and the inside of the cheek. This strip of tissue may become active while eating or speaking and can lift a denture from its alveolar ridge. This frenum attachment may be surgically moved (this is called a frenectomy).

Alveolar ridge bone profile lessens or literally comes closer to the floor of the mouth as jawbone is lost over time. The bone loss is called resorption. This reduces the vestibule or space between the lip and alveolar ridge. Surgical extension of this vestibule (called vestibuloplasty) provides more alveolar ridge exposure for a denture to rest upon and reduces muscle pull due to a high frenum attachment.

As an alveolar ridge loses bone, it often may be built-up by surgically placing various substances beneath the gum tissue to increase both bulk and height of the ridge. This is called alveolar ridge augmentation.

As a person eats and speaks, the lips and cheeks exert forces towards the inside of the mouth while the tongue exerts an outward counter force. There is a space between the tongue and lips and cheeks, called the neutral zone, where there are balanced forces during function. These opposing forces can help maintain a denture in place, with surprising power, if the denture is fabricated so that its bulk and teeth rest within this space.

Inserting metal implants into the jawbone and fabricating a lower denture to receive and connect with these implants in various ways will help stabilize a lower denture, while still allowing for comfortable and easy removal of the prosthesis for cleaning.

Ensuring that upper and lower teeth contact optimally during function (called balanced occlusion) is a basic means of stabilizing a lower denture. If one tooth strikes on one side only, the denture will rock. Even contact or biting is a necessity. Fabrication of a denture that completely avoids contact with all potentially dislodging structures and has a metal base for strength and some weight often will facilitate stability.

What's the Best Approach?

Frequently, several approaches are combined, and not all may be suitable for a particular patient. After a thorough examination, a licensed dentist can best advise an individual as to the best means of helping stabilize a lower denture in their unique situation.

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.

False Teeth: Porcelain vs. Plastic - Discover The Difference!

In the past, false teeth made with porcelain were generally preferred over false teeth made from plastic due to their greater durability and esthetics. However, in recent years, new generation biomaterials have resulted in the development of very wear-resistant false teeth made from plastic.

Clinically, the esthetics of plastic and porcelain denture teeth is nearly comparable, with good quality false teeth made from porcelain still being the standard for esthetics. However, the majority of dentures today probably are fabricated with false teeth made from plastic. For all practical purposes, the cost of porcelain and false teeth made from plastic are about the same.

While porcelain and plastic teeth are competitive with regards to durability, and to a lesser extent, esthetics and wear, there are other factors that may favor the selection of one type of tooth over another.

Some Selection Factors for False Teeth

Balanced bite and force transmission:

Denture bite (called occlusion) changes due to the constantly changing jawbone (called alveolar bone) upon which a denture rests, and, to varying degrees, uneven tooth wear resulting from use. Unless a denture is evaluated and its occlusion adjusted to a uniform and even contact (called balanced bite or balanced occlusion) at regular intervals, denture occlusion will become unbalanced.

Since false teeth made from porcelain are more wear-resistant, their occlusion will not become significantly self-altered by wear, as will false teeth made from plastic. However, when alveolar bone changes cause an unbalanced occlusion, the resulting biting forces from false teeth made from porcelain will be unevenly transmitted to underlying supporting alveolar bone. Frequent tissue refitting of the denture usually eliminates or lessens this problem.

Porcelain denture teeth tend to transmit the impact of biting forces to the alveolar ridge with greater intensity than that transmitted by plastic teeth in an unbalanced tooth contact situation. Some practitioners are of the opinion that this greater force, especially when uneven as in an unbalanced occlusion, may be damaging to the alveolar ridges and could result in accelerated bone loss.

Therefore, unless denture occlusion is checked and balanced on a regular basis, false teeth made from plastic would probably be a preferred choice over false teeth made from porcelain.

Bone loss:

If a person has lost a great deal of supporting alveolar bone and their gum tissue is not of a sturdy type, then plastic denture teeth might be a better choice. These teeth are more forgiving of excessive forces developing from habits such as clenching, grinding, and tapping or "clacking" of teeth, which seems to be more prevalent among older individuals. Plastic teeth do not transmit forces to underlying bone as intensely as false teeth made from porcelain.

Noise:

If false teeth made from porcelain are vigorously used or sometimes habitually tapped together, a "clacking" sound can be heard. Plastic teeth will muffle this sound and be quiet during normal function or habit jaw motions (called parafunction).

Which Type of Tooth Is Best?

If a person has been successfully wearing dentures with false teeth made from porcelain, then they should probably continue with false teeth made from porcelain. These teeth will not wear as fast as false teeth made from plastic, and the relationship between upper and lower jaws will tend to stay normal for a longer time than with false teeth made from plastic.

Regardless of which type of tooth is selected, the success of the selection is strongly based upon regularly checking dentures for proper balanced occlusion and fit on regular intervals.

If a denture is going to be worn against opposing natural teeth, then false teeth made from plastic should be selected because false teeth made from porcelain, being harder, could excessively wear natural teeth away.

After a thorough examination and frank discussion of what a person wants from wearing a denture, a licensed dentist can effectively discuss which type of tooth would best meet a particular individual's unique needs and desires.

Tooth Strength

Because false teeth made from porcelain are extremely hard in comparison to false teeth made from plastic, they tend to chip and crack more easily. For this reason, when dentures having false teeth made from porcelain are brushed and cleaned, they are generally handled over a sink filled with water or over a towel. Should the denture accidentally fall, the water or towel would help break the fall and hopefully reduce tooth breakage.

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.