Prosthodontics: Removable Prosthodontics (Dentures)

Prosthodontics is the branch of dentistry pertaining to the restoration and maintenance of oral function, comfort, appearance and health, by the restoration of natural teeth or the replacement of missing teeth with artificial substitutes.

Any artificial replacement of a missing body part, including teeth, is known as a prosthesis or prosthetic.

Complete Denture
A complete denture or a full denture is a removable prosthetic that replaces all teeth in the mouth. Facial muscles aid in the control and function of the denture. No matter how much care is take in the fabrication of a complete denture, it will never allow the same function as the natural dentition. Often success or failure of a denture is dependant on the tolerance the patient has for the difference. A complete denture is held in by the alveolar bone and oral mucosa, surrounding tissues and palatal structures.

Careful diagnosis and treatment planning are just as important in the fabrication of complete dentures as they are in any other dental treatment. The treatment plan must consider the need for surgery and the specific design of the appliance. Every aspect of the patient health must be considered; age, habits, jaw relationship, saliva flow, occlusion, dietary habits, aesthetic expectations, alternatives to complete denture, oral hygiene,and tori, are all useful in determining the appropriate plan for the patient.

Components of a Complete Denture

• Base: fits over the alveolar ridge and gingival tissue. It is usually made of tissue coloured acrylic. If additional strength is needed a wire mesh can be embedded in the acrylic.
• Flange: extends into the vestibule are facially as well as lingually or palatially.
• Post Dam: often described as the posterior palatal seal on a upper jaw complete denture. It extends across the entire palate behind the maxillary tuberosity.
• Denture Teeth: the teeth which are used in a complete denture can be made out of acrylic or porcelain. They are set to an acrylic base. A full denture will have 14 teeth in an arch as the wisdom teeth are excluded (there's usually no room for them anyways)

Partial Dentures
A removable prosthesis that replaces one or more teeth in an arch is referred to as a partial denture. There are many different designs, depending on the number of teeth that need to be replaced, and the strength of the remaining teeth, and weather the partial denture is to be a short term or long term replacement.

Components of a Partial Denture

• Partial Dentures
• Acrylic partial dentures are appropriate for a short term replacement of one or two teeth. The base is made from tissue coloured acrylic with artificial teeth attached. Thin wire clasps partially encircle teeth necessary to hold the acrylic partial in place.

• Cast partial dentures are considerably stronger, as there is a metal framework under and around the artificial teeth. The metal framework has the following components:
• Retainers (clasps): the clasps that surround the natural teeth to hold the partial denture in place
• a precision attachment can be placed instead of using a clasp to help prevent recurrent cavities around the clasps. A receptor is inserted into a crown on the abutment tooth and a matching component place into the partial denture.
• Connectors: the bars that connect the left and right sides of the partial denture
• Lingual connector: on the lower jaw, this is located inferior and lingual to the anterior teeth.
• Partial connector: on the upper jaw it may cross the palate
• Saddle or Denture base connectors: metal framework that will support the artificial teeth and denture base acrylic.
• Minor connector: links the major connectors to other areas of the metal framework.
• Rests: the part of the framework, extending from the retainers or connectors that will limit the seating of the partial denture. The rests sit on the occlusal or lingual surface of the teeth and help distribute the force of occlusion to the teeth rather than the alveolar ridge.
• Denture Base: tissue coloured acrylic that will retain the artificial teeth and enhance the aesthetics of the partial denture by covering the saddle portion of the framework and extending into the vestibular area.
• Artificial Teeth: come in a variety of shades and sizes that allow the partial denture to closely match the natural teeth. Usually, they are made of acrylic, but in some cases, porcelain teeth may be used.

Immediate Dentures
An immediate denture is one that is placed into the patients mouth at the same appointment as the extraction of teeth occurs. The new denture acts as a bandage during the healing phase. Try-in and evaluation of appearance are not possible in this situation.


Overdentures
Overdentures have more stability than complete dentures, and do not have visible clasps and retention issues associated with partial dentures. The alveolar ridges resorbs at a slower rate when the K9 teeth are retained for overdentures than when entirely edentulous (no teeth), also contributing to greater stability

The K9 teeth will need to be altered in circumference and height to enable the denture to completely cover them. A this reduced the thickness of the enamel, the remaining tooth structure must be covered by a thin metal covering known as a coping.

More often then not, the K9 teeth will have root canal treatment prior to coverage with coping to prevent any sensitivity.

Implants can also be put in to give retention, this is a lot more comfortable. The dentures snap onto the implants and are held firmly in place, but this is very expensive.

^ the K9's have been left                                                    ^ implants