The Art of Denture Fabrication

The first denture is a humbling and tense experience for both doctor and patient. Natural teeth, no matter how unhealthy or unaesthetic, are the patients own. Dentures are merely devices that the patient must learn to use. Just as a musician learns to play a trumpet or clarinet, the new denture wearer learns to use their new instruments to talk, eat and smile. Recreating or improving a smile with false teeth is an art. Unlike the art of a successful painter or sculptor, the dentist is most successful if no one notices the final product.

People choose dentures to replace their teeth when they have dental problems like severe periodontitis (gum disease), extensive tooth decay, accidental tooth loss, extreme wear, or very unaesthetic teeth. The author's earlier column, "A New Beginning - With Dentures", discusses the reasons people may choose to replace their teeth with full dentures.

Dentists begin to treat new denture patients by getting to know them. Dentists ask themselves, " What is this patient trying to achieve with dentures." "What does this patient expect?" "What does this patient know about dentures?" "How will this patient's health affect their outcome?" Every patient is different. Every dentist is different. Therefore, each denture treatment is different.

Dentures never feel like natural teeth. Denture wearers are only able to generate one fifth of the chewing force of healthy natural teeth. Well-fitted dentures slide around and move, because they are fully supported by soft, slick gum tissue. The use of dental implants, titanium fixtures that are surgically embedded in the bone, has revolutionized denture treatment by providing solid anchors for full dentures. Today, the state of the art in lower denture treatment includes the use of two to four implants to improve comfort.

The next step in denture fabrication is to examine the patient's mouth. The dentist will look for sores and blemishes that may be signs of disease. Ulcers, white patches and red patches are possible signs of oral cancer. The thickness and quality of the gum tissue is very important to the success of the full denture. Sometimes the bone under the gum shrinks and the gum does not. The resulting gum tissue is thick, soft and compressible. Dentists call this "redundant tissue". Redundant tissue is a poor base for a denture and should be removed before making the denture. Other gum conditions can cause future denture discomfort, and may be diagnosed and treated at this time.

Many dentists consider the denture impression the most important step. Imperfections in the impression affect the fit of the denture. There are many materials and techniques in use to take impressions for dentures. Most dentists have a favorite technique that they are comfortable with. The impression phase may take one or two visits depending on the technique.

Soon after the impressions are made, the dentist or technician fills them with plaster. Then, the dentist or technician makes thin trays; covered with thick, pink wax, on the plaster casts. These trays are called "wax rims".

The next appointment is a busy one. The dentist fits the wax rims to the patient's gums, and shapes the wax to show how the patient's teeth are to be set in the denture. The dentist and patient work together to choose the color, size and shape of the denture teeth from samples or by looking at photos of the patient's original teeth. A high school graduation or wedding photo comes in handy at this appointment.

After the appointment, the models of the gums are mounted on a hinge, called an articulator, which replicates the movement of the jaw joint. The dentist or dental lab technician sets the actual denture teeth into the wax rim to replicate, as closely as possible, the positions of natural teeth. Denture teeth must be set to work in concert with the tongue, lips and gums to maintain their position during use. For example, denture teeth that are set too far in front of the base of the denture cause the denture to be unstable during chewing.

During the try-in appointment, the dentist can adjust the teeth to satisfy the patient's aesthetic sense and to line up the teeth with the patient's facial features such as their eyes, the middle of their face and their lips. When the teeth of the wax denture are set up exactly as the patient and dentist like, the denture is returned to the dental lab for finishing.

In the dental lab, the denture is put into a metal container; the container is filled with plaster around the wax denture. The wax is melted out of the container, and replaced with a soft mixture of acrylic. The acrylic filled mold is kept under pressure to prevent air bubbles and heated to harden the acrylic more thoroughly. After several hours, the lab technician breaks the denture out of the mold, polishes it and returns it to the dentist.

The dentist fits the denture to the patient by lining the inside of the denture with a white paste, pressing the denture into place and checking the underside for high spots. Then the patient bites on carbon paper so that the dentist can evaluate the way the teeth meet.
When the denture is comfortable, the dentist or dental assistant instructs the patient in proper care of their new teeth. Dentures must be brushed inside and out twice a day. Plaque and tarter will form on dentures the same as on natural teeth. Also, the patient will have to learn to speak and eat with their new teeth.

Patients usually take days or weeks to become used to wearing complete dentures. To become accustomed to speaking with new dentures, read the newspaper aloud in front of a mirror. Eating with dentures may be difficult at first. Start with a soft diet. Always cut firm and chewy foods into small pieces. Denture wearers loose some of their sense of taste, so plan to add more spice to food than before.
Most dentists will want to see their new denture-wearing patients for follow up appointments the next day and the next week. At these appointments, the dentist will check for denture sores, answer questions, and check on the patient's progress with their new teeth.

A complete denture that restores or improves appearance and provides acceptable function is a point of pride to dentists, dental lab technicians, and patients. If you believe that you are in need of this service, speak with your dentist or choose a dentist who works with dentures routinely.

Dr. David Leader has practiced in Malden since 1989. He is the Chairman of the Health Advisory Committee of the Lynnfield Schools, a member of the Professional Advisory Committee of Tri-CAP Head Start, a member of the department of general dentistry of Tufts University School of Dental Medicine, and is a member of the Mass Dental Society Council on Dental Care and Benefits Programs. His past columns are available on the Web http://leaderdmd.dentistryonline.com. Address comments and questions to David.Leader@Tufts.edu .