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



Procedures and Materials Required for Constructing Different Types of Dentures

Partial Denture Procedure

• Appointment One - Records
• gather all information necessary for an accurate diagnosis and treatment plan. This includes intraoral photos, accurate records, x-rays, and study casts. The mouth must be in optimal dental health, including fillings, periodontal treatment, and oral surgery as the patient requires. Custom impression trays must be fabricated prior to the second appointment.
• Appointment Two - Prep and Impression
• custom impression trays are used with the elastomeric impression material. A wax bite registration is necessary to articulate the upper and lower models accurately in the lab. The shade is recorded for any artificial teeth and this plus the suggested design is sent to the lab for preliminary constructions
• Appointment Three - Try-In
• dentist will try in the cast partial denture framework to evaluate the fit. Adjustments are made if nessissary.
• Appointment Four - Delivery
• the dentist will try in the finished partial denture and make nay minor adjustments necessary to the occlusion or clasp pressure
• Follow Up Appointments: post-delivery checks and adjustments will be made at the discretion od the dentist and patient. Patient must keep a regular recall schedule for the remaining teeth and the denture will be checked each time.

Complete Denture Procedure

•  Appointment One - Records
• gather all information necessary for an accurate diagnosis and treatment plan. This includes intraoral photos, accurate records, x-rays, and study casts. The mouth must be in optimal dental health, including fillings, periodontal treatment, and oral surgery as the patient requires. Custom impression trays must be fabricated prior ot the second appointment.
• Appointment Two - Final Impressions
• final impression is fabricated. Muscles mold the impression. This impression is sent to the lab. Often a photograph of the patient with natural dentition is included so the technician is able to accurately recreate the original appearance. The patient will have input as to the shade and shape of the teeth and the type of material used (plastic or porcelain)
• Appointment Three - Try-in of Baseplates and Occlusal Rims
• occlusal rims are used to achieve the correct vertical dimension (which is the space occupied by the teeth in occlusion so that the TMJ is in correct position). Dentist will also determine were mid line should be. Smile line for the denture must be determined. Lastly the occlusion is checked.
• Appointment Four- Try-in
• a wax denture is tried in to see if any alterations need to be made. This may take several appointments before the patient and dentist are satisfied with aesthetics and function.
• Appointment Five- Delivery
• assess the final aesthetics and functions by chewing, talking, smiling etc. high spots are located, and adjusted.
• Appointment Six- Post-Delivery Check
• two or three days after the denture have been delivered the dentist will want to check the oral mucosa doe signs of excessive pressure or irritations. Adjustments can be made at this time. Once all is satisfactory a 6 month recall schedule can be established.
• Follow-Up Appointments
• all patients with dentures should be seen by their dentists at least once a year, for examination of the oral cavity and evaluation of the denture.

Immediate Denture Procedure

• Appointment One - Records
• impressions are taken, and photos of the anterior teeth are taken for aesthetic replication
• Appointment Two - Occlusal Rims and Bite Registrations
• dentist will ensure correct vertical dimension then lock the maxillary rim to the mandibular rim with an adhesive.
• Appointment Three- Extractions and Insertion
• all the remaining teeth will be extracted. The denture will be placed
• Appointment Four and Beyond - Suture Removal and Post-op Checks
• once the swelling decreases, the dentures will become loose.

Post Op Instructions

• keep dentures in place for the first 24 hours. If it is removed the bleeding may not stop and there may be swelling that will not allow its reinsertion
• return to the office the day after surgery. The dentures will be briefly removed for cleaning and assessment of the healing ridge.
• after the second day the denture may be removed briefly to facilitate cleaning and rinsing of the oral cavity
• the suture will need to be removed in 3-5 days. At that time, the dentist will make necessary adjustment as the alveolar ridges heals
• when healing of the alveolar ridge is complete, the dentures will require permanent relining with acrylic to customise the fit and enable retention.

How to Take Care of Your Dentures, and Your Oral Tissues

• Remove the denture and thoroughly rinse the oral cavity at least once a day
• the denture must be cleaned daily with a denture brush and running water or specialised denture paste, or use an effervescent denture cleaning preparations - avoid regular toothpaste as it is too abrasive.
• if cleaning the denture by hand, hold it over a sink containing cool water or a towel in case it is dropped.
• do not soak the denture in hot water, bleach or any other chemical not specifically formulated for denture cleaning
• do not wear dentures at night - this allows the oral tissues to hydrate and oxygenate
• when the denture are out of the mouth, they must be kept in a moist, airtight container to prevent drying, warping and damage.

Advantages and Disadvantages of Dentures

Advantages

•  great smile, and natural appearance
• last a long time when properly taken care of (typically they last from 5-10 years)
• can correct many problems such as speech or chewing for some patients

Disadvantages

•  very high maintenance
• can cause initial speech problems
• mouth irritation and sores can occur caused by not removing your dentures
• chewing force is a lot weaker
• can reduce the taste of food when having a complete upper denture

Denture Sores

Denture sores are caused when the patient does not remove the dentures on a regular basis, therefore the tissue doesn't have a chance to breathe. This can be very painful

 

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