What are Removable Dentures?
Removable dentures (sometimes referred to as false teeth or plates) are a common treatment alternative for missing teeth. Removable dentures are versatile in their ability to replace any number of missing teeth and to fill out the contours of the face and lips, which shrink inward when multiple teeth are lost. Typically the denture base is made of acrylic plastic that can be tinted to match the patient’s natural gum tissues. The teeth are made from either acrylic or ceramic.
Figure 1 shows different views of a complete removable denture for the patient’s upper jaw (maxilla). The upper left photograph shows the side of the denture that is worn against the patient’s gums, where their teeth used to be. Note that the denture base (the pink part that holds the teeth and rests on the gum tissues) covers the roof of the mouth (palate), and adds bulk on the side towards the lips and cheeks to give the face proper contours. The lower right photograph shows how the denture will function with the patient’s lower denture. Ideally, upper and lower dentures are made in sets for patients with no teeth (completely edentulous). This provides the best chewing efficiency and esthetics.
Complete removable dentures are an option for the completely edentulous patient, while partial removable dentures (partials) are an option for the partially edentulous. Partial removable dentures are held in place in the mouth by wire clasps and/or other means of attachment to the remaining natural teeth. Partial dentures can be a temporary means of treating patients who are expecting to lose the remaining teeth. As more teeth are lost, they can be added to the partial. At some point, as the natural teeth being used to anchor the partial denture (abutments) are lost, it becomes necessary to completely remake the denture, or explore other treatment options, like bridges or dental implants—both of which are usually good solutions for the replacement of single teeth as well.
Complete removable dentures are held in place by some combination of “suction cup effect”, denture adhesive (best if used very minimally), and the patient’s controlled use of their tongue and facial muscles. Learning to function with complete removable dentures can be a challenge, as with any prosthetic device. Dental implants can also be used to help stabilize dentures, and often significantly improve a patient’s quality of life.
Figure 4 shows a partial removable denture for the lower jaw (mandible). Note that the denture replaces all but three of the patient’s natural teeth, which will be used to retain the denture in place in the mouth. This denture has a swing lock clasping feature, consisting of a hinged bar, shown in the open position. The swing lock will not be visible behind the patient’s lower lip when the denture is placed in the mouth. The ability to remove the denture makes it much easier to clean such retention features. Not evident from the photograph is that the metal framework which serves as the denture’s skeleton extends under the pink plastic gum tissue and denture teeth to strengthen them. Generally the framework is made of an extremely hard nickel-chrome alloy; however, for those with nickel allergies, other materials can be used.
The process of creating and placing Removable Dentures
Before the removable dentures are made
Although not an invasive procedure itself, having removable dentures made may require other procedures to be performed. Some are considered to be part of the denture fabrication process. Others are separate billable procedures from the denture (for example, preliminary surgery, dental implants, etc.). It’s important to understand any costs involved before undertaking treatment. Your dentist can provide a detailed list of the procedures he/she recommends. Some of the related procedures may be surgical, and require the use of local anesthetic.
For any before-dentures (pre-prosthetic) procedures which are surgical, the dentist will review your health history. If you have replacement joints (for example, total knee replacement, hip replacement, etc.), you may be pre-medicated with antibiotics for the procedure. If you have certain types of heart murmurs or replacement heart valves, you may also need to take an antibiotic pre-medication prior to the procedure.
If you are anxious about dental procedures, your dentist may recommend sedating you for the procedure. There are several methods of relaxing patients for dental treatment, including oral anti-anxiety pills; inhaled anti-anxiety medication like nitrous oxide; and intravenous anti-anxiety medication.
With a wide degree of variation, the following paragraphs summarize the steps involved in having dentures made. Your procedure may vary from these steps, depending on your individual needs.
Step 1: The diagnostic records appointment
In order to produce a good treatment plan, diagnostic information must be gathered. When dentures are an option, the dentist will often expose a panoramic radiograph or cone beam (CBCT) scan to visualize the amount of remaining bone that is present on which to support the dentures. Periapical radiographs may be exposed of any abutment teeth to evaluate their structural worthiness for anchoring partial dentures. Bitewing radiographs may be exposed to rule out tooth decay.
Close attention is paid to the location of the mental nerves in the lower jaw (mandible), because it can be very painful to wear dentures that place pressure on or near these nerves (one per side). The radiographs are also studied for signs of disease process (for example, cysts, tumors, etc.). An evaluation is made of the shape of the palate and oropharynx. Preliminary impressions of the edentulous arches are made and poured in dental stone to produce cast replicas of the teeth and edentulous arches.
An interocclusal bite record is produced that indexes how the upper and lower jaws are positioned relative to one another. A measuring device called a facebow (Figure 5) is sometimes used to determine the relative positions of the upper jaw (maxilla) and the jaw joints. This device is used to accurately mount the plaster cast replicas of the dental arches in a jaw simulation tool called an articulator (Figure 6).
These preliminary study casts can help to determine whether preliminary surgical procedures will be required, where alterations to the remaining teeth may need to be made, whether and where dental implants may be recommended, and a variety of other treatment-planning information. They are also used to make custom impression trays for the final impressions, which need to be very accurate.
Step 2: The second appointment for removable dentures
The second appointment covers custom tray impressions, rest preparations, guide planes, and tooth selection.
If either of the dentures is a partial denture, rest preparations and guide planes may need to be milled into the abutment teeth (the ones that anchor the partial).
Generally the rest preparations are made after using the study casts to plan where they should go. Denture tooth shade and shape will be determined. A procedure called border molding may be completed. Basically, this involves determining how far to extend the denture for maximum retention, and to provide correct support for the lips and cheeks (how far it should extend, and how bulky it should be). A final impression of the jaws will be made using custom trays made from the preliminary impressions at the first appointment.
Step 3: Wax try-in / Frame try-in
A wax version of the removable dentures will be tried in the patient’s mouth (the teeth are set in rigid pink wax). The tooth position, bite plane location (where the upper and lower denture teeth will contact), phonetics and appearance will be evaluated while it’s still possible to move the teeth and re-shape the bite plane. If the denture is a partial, its supporting framework is evaluated for passive fit (to be sure it’s not putting pressure on teeth); retentiveness (to see whether the clasps will hold it in place effectively); and function with the opposing teeth (to be sure the patient won’t be biting down on the metal framework).
When everything is adjusted properly, the denture will be returned to the laboratory for processing in acrylic. If the patient is completely edentulous, Step 3 may require two appointments—one to establish the proper facial contours and vertical separation of the jaws, and one for the wax try-in.
Step 4: The delivery of removable dentures
On the date of delivery, the denture will be placed in the mouth, and the bite will be adjusted. Pressure spots will be eliminated and specific instructions given on the wear and care of the removable denture(s). Frequently, your dentist will recommend a 24-hour follow-up to inspect the dentures and oral tissues. Multiple follow up appointments are commonly necessary over several months time.
Some advantages and benefits of Removable Dentures
- Excellent cosmetic results can be obtained with dentures.
- Dentures are a cost-effective way to replace numerous teeth.
- Having teeth to clasp makes removable partial dentures much more stable and retentive than removable complete dentures.
- Being able to remove a denture allows better access for oral hygiene, and allows the tissue under the denture to rest. Dentures are easier to clean than fixed bridgework, which is not removable by the patient.
- Chewing efficiency with a partial denture can approach that of natural teeth, allowing for proper nutrition.
- Chewing efficiency with complete dentures, although significantly compromised from that of natural teeth, is far better than that of the untreated edentulous patient.
- Replacing missing teeth with a partial denture can help to avoid problems associated with teeth shifting and loss of vertical dimension of occlusion (bite collapse), a condition in which the lower jaw rotates further closed than normal following the loss of multiple back teeth.
- Dentures can be used to restore proper facial contours, eliminating the sunken cheeks and “purse-string” wrinkles commonly seen around the mouths of edentulous patients.
Potential disadvantages and risks of Removable Dentures
Frequent adjustments to the bite, the denture framework, clasps, or relines of the tissue bearing surface of the denture may become necessary.
Improperly adjusted removable partial dentures can apply leverage to the remaining teeth, which can damage or break them. Even well-adjusted partial dentures can apply leverage through chewing that can loosen or damage the abutment teeth.
Food can lodge under the denture, requiring frequent removal for cleaning.
Retention clasps can break or bend, requiring repairs/adjustments.
Some individuals have an especially difficult time adapting to removable complete dentures. With complete dentures, chewing efficiency is greatly reduced compared to natural teeth. Depending on how much bone remains following removal of the teeth, even dentures that fit the jaws well may be difficult to keep in position.
Dentures apply pressure to the underlying soft tissues and bone, which may shrink (resorb) over time. This can make the denture fit poorly, and may make future dental procedures more difficult.
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