Denture

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					                                      Denture
Den1tures, also known as false teeth, are prosthetic devices constructed to replace
missing teeth; they are supported by the surrounding soft and hard tissues of the oral
cavity. Conventional dentures are removable. However, there are many different
denture designs, some which rely on bonding or clasping onto teeth or dental
implants. There are two main categories of dentures, the distinction being whether
they are used to replace missing teeth on the mandibular arch or on the maxillary arch.

Causes of tooth loss

Patients can become entirely edentulous (without teeth) for many reasons, the most
prevalent being removal because of dental disease typically relating to oral flora
control, i.e., periodontal disease and tooth decay. Other reasons include tooth
developmental defects caused by severe malnutrition, genetic defects such as
dentinogenesis imperfecta, trauma, or drug use.

Advantages

Dentures can help patients through:

    1. Mastication, as chewing ability is improved by replacing edentulous areas
       with denture teeth.
    2. Aesthetics, because the presence of teeth gives a natural appearance to the
       face, and wearing a denture to replace missing teeth provides support for the
       lips and cheeks and corrects the collapsed appearance that results from the loss
       of teeth.
    3. Pronunciation, because replacing missing teeth, especially the anteriors,
       enables patients to speak better. There is especially improvement in
       pronouncing words containing sibilants or fricatives.
    4. Self-esteem, because improved looks and speech boost confidence in the
       ability to interact socially.

Types

Removable partial dentures

Removable partial dentures are for patients who are missing some of their teeth on a
particular arch. Fixed partial dentures, also known as "crown and bridge" dentures,
are made from crowns that are fitted on the remaining teeth. They act as abutments
and pontics and are made from materials resembling the missing teeth. Fixed bridges
are more expensive than removable appliances but are more stable.

Complete dentures

Complete dentures are worn by patients who are missing all of the teeth in a single
arch (i.e., the maxillary (upper) or mandibular (lower) arch).
1Denture
2 Denture-Repair.com
History

Around 700 BC, Etruscans in northern Italy made dentures out of human or other
animal teeth. These deteriorated quickly but, being easy to produce, were popular
until the mid-19th century.

The oldest useful complete denture appeared in Japan, and has been traced to the
Ganjyoji temple in Kii Province, Japan. It was a wooden denture made of Buxus
microphylla, and used by Nakaoka Tei (–20 April 1538). This wooden denture had
almost the same shape as modern dentures retained by suction. It was also shaped to
cover various conditions of teeth loss. Wooden dentures were used in Japan up until
the Meiji period.

London's Peter de la Roche is believed to be one of the first 'operators for the teeth',
men who advertised themselves as specialists in dental work. They were often
professional goldsmiths, ivory turners or students of barber-surgeons. US President
George Washington is famously known for his dentures, which were made with ivory
from hippos and elephants as well as gold, rivets, spiral springs and even real human
teeth.

The first porcelain dentures were made around 1770 by Alexis Duchâteau. In 1791,
the first British patent was granted to Nicholas Dubois De Chemant, previous
assistant to Duchateau, for 'De Chemant's Specification',

   "a composition for the purpose of making of artificial teeth either single double or
in rows or in complete sets, and also springs for fastening or affixing the same in a
more easy and effectual manner than any hitherto discovered which said teeth may be
made of any shade or colour, which they will retain for any length of time and will
consequently more perfectly resemble the natural teeth."

He began selling his wares in 1792, with most of his porcelain paste supplied by
Wedgwood.

In London in 1820, John Lennon, a goldsmith by trade, began manufacturing high-
quality porcelain dentures mounted on 18-carat gold plates. Later dentures from the
1850s on were made of Vulcanite, a form of hardened rubber (Claudius Ash’s
company was the leading European manufacturer of dental Vulcanite) into which
porcelain teeth were set. In the 20th century, acrylic resin and other plastics were
used.[7] In Britain sequential Adult Dental Health Surveys revealed that in 1968 79%
of those aged 65–74 had no natural teeth; by 1998, this proportion had fallen to 36%.

Fabrication of complete dentures

Modern dentures are most often fabricated in a commercial dental laboratory or by a
denturist using a combination of tissue shaded powders polymethylmethacrylate
acrylic (PMMA). These acrylics are available as heat cured or cold cured types.
Commercially produced acrylic teeth are widely available in hundreds of shapes and
tooth colors.

The process of fabricating a denture usually begins with an initial dental impression
of the maxillary and mandibular ridges. Standard impression materials are used during
the process. The initial impression is used to create a simple stone model that
represents the maxillary and mandibular arches of the patient's mouth. This is not a
detailed impression at this stage. Once the initial impression is taken, the stone model
is used to create a 'Custom Impression Tray' which is used to take a second and much
more detailed and accurate impression of the patient's maxillary and mandibular
ridges. Polyvinylsiloxane impression material is one of several very accurate
impression materials used when the final impression is taken of the maxillary and
mandibular ridges. A wax rim is fabricated to assist the dentist or denturist in
establishing the vertical dimension of occlusion. After this, a bite registration is
created to marry the position of one arch to the other.

Once the relative position of each arch to the other is known, the wax rim can be used
as a base to place the selected denture teeth in correct position. This arrangement of
teeth is tested in the mouth so that adjustments can be made to the occlusion. After the
occlusion has been verified by the dentist or denturist and the patient, and all phonetic
requirements are met, the denture is processed.

Processing a denture is usually performed using a lost-wax technique whereby the
form of the final denture, including the acrylic denture teeth, is invested in stone. This
investment is then heated, and when it melts the wax is removed through a spruing
channel. The remaining cavity is then either filled by forced injection or pouring in
the uncured denture acrylic, which is either a heat cured or cold-cured type. During
the processing period, heat cured acrylics—also called permanent denture acrylics—
go through a process called polymerization, causing the acrylic materials to bond very
tightly and taking several hours to complete. After a curing period, the stone
investment is removed, the acrylic is polished, and the denture is complete. The end
result is a denture that looks much more natural, is much stronger and more durable
than a cold cured temporary denture, resists stains and odors, and will last for many
years.

Cold cured or cold pour dentures, also known as temporary dentures, do not look very
natural, are not very durable, tend to be highly porous and are only used as a
temporary expedient until a more permanent solution is found. These types of
dentures are inferior and tend to cost much less due to their quick production time
(usually minutes) and low cost materials. It is not suggested that a patient wear a cold
cured denture for a long period of time, for they are prone to cracks and can break
rather easily.

Problems with complete dentures

Problems with dentures may arise because patients are not used to having something
in their mouth that is not food. The brain senses the appliance and interprets it as
'food', sending messages to the salivary glands to produce more saliva and to secrete it
at a higher rate. This usually only happens in the first 12 to 24 hours, after which the
salivary glands return to their normal output. New dentures can also be the cause of
sore spots as they compress the denture bearing soft tissues (mucosa). A few denture
adjustments in the days following insertion of the dentures can take care of this
problem. Gagging is another problem encountered by a minority of patients. At times,
this may be due to a denture that is too loose, too thick or extended too far posteriorly
onto the soft palate. At times, gagging may also be attributed to psychological denial
of the denture. Psychological gagging is the most difficult to treat since it is out of the
dentist's control. In such cases, an implant-supported palateless denture may have to
be constructed. Sometimes there could be a gingivitis infection under the completed
dentures, caused by the accumulation of dental plaque. One of the most common
problems for wearers of new upper complete denture is a loss of taste sensations.

Costs

If dentures are medically necessary, insurance might pay 15%-80% of the costs (up to
the plan's annual limit, if there is one). Some discount dental plans may also cover
some of the cost of purchasing dentures.

A low-cost denture starts at about $300–$500 per denture, or $600–$1,000 for a
complete set of upper and lower dentures. These tend to be cold cured dentures, which
are considered temporary because of the lower quality materials and streamlined
processing methods used in their manufacture. In many cases, there is no opportunity
to try them on for fit before they are finished. They also tend to look artificial and not
as natural as higher quality, higher priced dentures.

A mid-priced (and better quality) heat cured denture typically costs $500–$1,500 per
denture or $1,000-$3,000 for a complete set. The teeth look much more natural and
are much longer lasting than cold cured or temporary dentures. In many cases, they
may be tried out before they are finished to ensure that all the teeth occlude (meet)
properly and look esthetically pleasing. These usually come with a 90-day to two-year
warranty and in some cases a money back guarantee if the customer is unsatisfied. In
some cases, the cost of subsequent adjustments to the dentures are included.

Premium heat cured dentures can cost $2,000-$4,000 per denture, or $4,000-$8,000 or
more for a set. Dentures in this price range are usually completely customized and
personalized, use high-end materials to simulate the lifelike look of gums and teeth as
closely as possible, last a long time and are warranted against chipping and cracking
for 5–10 years or longer. Often the price includes several follow-up visits to fine-tune
the fit.

				
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Description: A low-cost denture starts at about $300–$500 per denture, or $600–$1,000 for a complete set of upper and lower dentures.