Fixed Prosthodontics and Provisional Coverage Flashcards
Fixed Prosyhodotincs: Indications
Fixed prosthodontices is the specialized area of dentistry devoted to the replacement od the missing teeth. A dental prothesis is necessary to replace missing teeth. Fixed prostheses are cemented into place and are not removable like a traditional denture
Indications for mixed prosthodontics include the following:
1: One or two adjacent teeth are missing in the same arch
2: The supportive tissues are healthy.
3: Suitable abutment teeth are present.
4: The patient is in good health and wants the prosthesis placed
5: The patient has the skilled and motivation to maintain good oral hygiene.
Fixed prosthodontic: contraindications
contraindications for fixed prosthodontics include the following:
1. The supportive tissues are diseased or missing.
2. subitable abutment teeth are not present.
3. The patient s in poor health.
4. The patient is not motivated to have the prosthesis placed.
5. The patient has poor oral hygiene habits
6. The patient cannot afford the treatment.
Inlays, onlays and Procelain Veneers
Inlays and onlays are two types of cast restoration. An inlay covers the proximal surface and only a portion of the occlusal surface. An onlay covers the proximal surface and most or the entire occlusal surface. Cusp tips are involved.
Porcelain veneers are a thin, shell-like covering to iimprove the appearance of anterior teeth by covering defects such as hypocalcification and intrinsic stains. An opaquer can be used to block out ny underlying color or structural defects. The cement used for veneers also can be shahed to enhance color match.
Crowns
Crowns are another type of fixed prosthodontics .there are several types of crowns listed here.
_ Full crown: completely covers that anatomic crown of an individual tooth. The full crown are used when a tooth has decay so severe that reconstruction cannot be performed with the use of a direct restoration.
- Three Quarter crown: covers the anatomic crown of a tooth except a healthy buccal, facial, or lingual portion. The healthy portions saved and the rest of tooth is restored with a crown.
- Porcelain fused to metal (PFM) crown is full metal crown with outer surface covered with a veneer of porcelain. With a PFM, porcelain is added foe aesthetic reasons and matched to natural teeth.
- Porcelain jacket crown: us a very thin metal shell covered by layers of porcelain to resemble the shading and translucence of the enamel of natural tooth.
Bridges and Implants
A fixed bridge is a prosthesis for missing teeth within the same arch. It contains a series of two or more units and is cemented permanently in place.
A resin-bonded bridge, alos known a Maryland bridge, has winglike extensions coming from the proxmial sides that are bonded onto the lingual surfaces of the teeth adjacent to the mission tooth.
An implant is a screw-like device tha is implanted into the mandibular or maxillary bone to replace a missing tooth, or teeth. If the patient has suffcient bone, this is another for bridge placement
Overview of a fixed prosthodontic procedure: preparation
A crown procedure or other fixed prothodontics procedures begin with shade selection. A shade guide which contains samples of all available shades used to match the natural tooth color. When selecting a shade, be sure to:
- Moisten the color aple to achieve a more accurate match
- use natural sunlight.
-record shade on the shade on the patient record and on the laboratory prescription.
- The tooth must be prepared for the cast restoration. It must be able to slide into place and withstand the forces of occlusion. Both rotary and hand-cutting instruments are used in the preparation process as follows:
- Rotary instruments
- Hand cutting and rotary instruments
Retention aids provide additional support for the crown if the tooth is extensively decayed or fractured or has been endodontically treated:
- core buildup
-pin retention
- post and core
Overview of a fixed prosthodontic procedure: Gingival Retraction
A retraction cord: is positioned around the prepared tooth. The cord temporarily displaces the gingival tissue and widens the gingival sulcus so that impression material can be flow around all parts of the preparations:
- Nonimpregnated: cord without chemicals added.
- impregnated: cord with an astringent and vasoconstrictor added. The astringent helps shrink the tissue, while the vasoconstrictor minimizes bleeding.
Transfer is performed with the use of cotton oilers.
Packing is easier when the tissues are dry. Typically hemostatic solution is placed after the cord has been successfully packed, but sometimes bleeding needs to be controlled before or during placement of the cord.
Overview of a fixed prosthodontic procedure: final impression
It’s critical that the final impression be accurate so that dental laboratory technicians fabricate the restoration correctly. An inaccurate impression will result in an inaccurate fabrication, leading to additional appointments for the patient.
Always as the denist which type of elastomeric material will be used for the final impression.
The bite registration provides the laboratory technician with a reproduction of a patient’s bite and opposing each regstration for designing the anatomic structures of the fixed prosthetic:
- Open bite
-Closed bite
Elastomeric Impression Material: Used yo create an extremely accurate impression.
Light -Bodied Material: Mixed and applied around the prepared tooth.
Heavy-Bodied Material: Mixed and loaded into a tray to be seated on the quadrant or arch.
Overview of a fixed prosthodontic procedure: provisional restration
Provisional coverage is used for patient comfort for the period between tooth preparation to final cementation of fixed prosthetic. provisional coverage does the following:
- Reduces sensitivity and discomfort
- maintains function and aesthetics
- protects the margins
-prevents shifting
The temporary restoration is made to last long enough for the dental laboratory technicians for fabricate the permanent restoration. Good contact and occlusion are important in fabrication of the provisional restoration.
When the permanent restoration is read, the temporary one is removed. After the casting has been fitted and is acceptable , the dentist cements the casting.
Overview of a fixed prosthodontic procedure: Provisional restoration(cont’d)
The preparation and set up for a fixed bridge is similar to that of a fixed single crown. The primary difference is the number of teeth prepared. The abutment teeth are prepared for full crowns or onlays, followed by tissue management, impressions, and then provisional coverage is applied. The final steps are also similar to those for a single crown: impressions, bite registration, and lab prescription are all sent to the laboratory for fabrication.
At the second appointment, the dentist places the framework on the prepared teeth and checks the margins. If the framework fits, the dentist will take an impression with the framework in, and then upon removal, the framework will be left in the impression. This allows the laboratory to know the position and shape of the soft tissue. If it does not fit, the dentist can cut the framework to get individual abutments to fit or a new impression can be taken.
At the third appointment, the dentist will cement the bridge in place. The dentist will fit the bridge and make any necessary adjustments. All margins, occlusions, and contacts will be checked before final cementation takes place.
Overview of a fixed proshthodontic procedure: delivery and home care.
Good home care is essential for the maintenance of a fixed prosthesis. the patient should e instructed to carefully brush the fixed prosthesis and its supporting tissues every day. In addition, the patient should use a bridge threader to thread dental floss under the pontic and into the sulcus at both abutments of the bridge.
Custom Provisional Coverage
A custom provisional coverage is designed specifically for the needs of each patient. It is the most versatile provisional coverage for crown and bridge preparations. It can be used for posterior or anterior crowns or bridges. It provides the best fit and is most natural-looking because different shades of acrylic are available.
There are two types of provisional coverage covered here.
Custom Provisional Coverage: Custom Provisional coverage is protective covering designed specifically for the needs of the patient, that is worn temporarily while fixed prosthesis is being fabricated in the dental laboratory.
Prefabricated Provisional Coverage: Prefabricated provisional coverage is a preformed crown available in a variety of shapes and sizes that is trimmed and adjusted to fot a prepared tooth or teeth while the final restoration is being fabricated
Benefits of Fabricating Custom Provisional Preparations
The benefits of fabricating custom provisional preparations include the facts here.
1:The coverage is esthetically acceptable to the patient.
2: The contours are similar to those of the natural tooth.
3: The cervical margin is smooth and fits snugly.
4: The occlusal surface is aligned with the occlusal plane of the adjacent teeth.
5: When cemented, the provisional coverage remains stable, stays in place, and is comfortable for the patient.
6: The provisional coverage can be easily removed without damage to the tooth or adjacent tissues
preformed Polymer Crowns
Direct techinque is the most common way dentists custom-fabricate a provisional restoration. During this process, the dentist makes the provisional restoration directly on the patient’s tooth. This method is efficient and cost-effective.
The indirect technique is more time-consuming and requires the creation of impressions for a study model. The study model is used to fabricate the temporary crown.
preformed crown are availbele in a variety of shapes and size that are trimmed and adjusted to fit prepared tooth or teeth while the final restoration is being fabricated. The advantages of a prefabricated crown are availability and cost savings. Prefabricated restorations are best used for single until temporary crowns.
preformed shell like crowns are designed specifically for premolars and molars. Shells are made of polymer materials designed with anatomic features of natural teeth. A preformed polymer available for single crowns and bridgework. A composite resin bonds the preformed crown to the teeth.
Preformed polycarbonate crowns
Preformed polycarbonate crowns are commonly used in cases involving fracture of an anterior tooth. As a result of the missing tooth structure, no preliminary impression can be taken. These crowns have easy grab tabs and are easily adjusted. They can be lined with acrylic for a better fit.
Tooth colored crown are selected for anterior teeth, where appearance is important. They are
- Available in a variety of size, shapes and shades
- easily adapted to margins
- suitable for short or long use.
Aluminum crowns: are designed specifically for premolars and molars such crowns are available in a range of size for posterior teeth. The surface of aluminum crowns can be anatomic or non anatomic. The aluminum crown is sized, contoured and cemented in place.
celluloid crowns: are used only on premolar and anterior teeth. these clear crown forms are lined with provisional resin materials and are removed prior temporary cementation.
