Dental Provisional Restoration and Crowns

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Questions and Answers

What is the main purpose of a provisional restoration?

To protect the prepared tooth or teeth and keep the patient comfortable while a permanent restoration is being fabricated.

Which of the following is NOT a requirement for a good provisional restoration?

Perfect fit with no gaps (correct)

Ease of cleaning

Positional stability

Occlusal function

Strength and retention

Esthetic appearance

Pulpal protection

Impinging margins on a provisional restoration can lead to gingival hypertrophy.

True

What are the two main types of metal crowns used for provisional restorations?

Flat-topped cylindrical Signup and view all the answers

What is the main disadvantage of metal crowns for provisional restorations?

Unpleasant taste Signup and view all the answers

What is the primary material used in a celluloid crown form?

Celluloid Signup and view all the answers

During the clinical procedure for a celluloid crown, why is it important to coat the prepared tooth with Vaseline?

To facilitate the removal of the crown. Signup and view all the answers

What is the primary benefit of using acrylic ready-made crowns for anterior teeth?

They come in different sizes and shades. Signup and view all the answers

The clinical procedure for an acrylic ready-made crown is the same as that of an aluminum crown.

True Signup and view all the answers

Why are there two postoperative impressions taken for the indirect method of custom provisional crown fabrication?

To prevent tooth irritation. Signup and view all the answers

What is the main advantage of using the indirect method for custom provisional crowns?

Better margin accuracy Signup and view all the answers

For a fixed bridge restoration, the provisional restoration should be individual crowns for each prepared tooth.

False Signup and view all the answers

What is the thickness of the celluloid sheet used to create a provisional bridge?

1-4 mm Signup and view all the answers

What is the purpose of leaving half a tooth on each side of the celluloid sheet when fabricating a provisional bridge?

These act as stoppers to control the placement of the resin during the fabrication process. Signup and view all the answers

What is the purpose of adding a paper clip or wire to the canal of a standard acrylic crown when fabricating a custom provisional post crown?

It allows for the removal of the crown after setting. Signup and view all the answers

What is the most common base for temporary cements?

Zinc oxide and eugenol. Signup and view all the answers

Study Notes

Provisional Restoration (Temporary Restoration)

Important for protecting prepared teeth and keeping patients comfortable during fabrication of a permanent restoration.
A good provisional restoration must meet these requirements:
- Pulpal Protection: Prevent temperature extremes and saliva leakage.
- Positional Stability: Prevent tooth movement (extrusion, drifting).
- Occlusal Function: Allow for proper chewing function and prevent tooth migration.
- Easy Cleaning: Maintain oral health and prevent post-cementation issues.
- Non-Impinging Margins: Prevent gingival irritation, inflammation, or hemorrhage.
- Strength and Retention: Resist forces without fracturing.
- Esthetics: Provide acceptable appearance in some cases.

Types of Ready-Made Crowns

Metal Crowns: Commonly used for posterior teeth.
- Made of stainless steel, nickel-chromium, or aluminum (aluminum is more pliable).
- Two types: Flat-topped cylindrical & morphologically contoured.
- Disadvantages: Unpleasant taste, poor aesthetics, and rapid wear.

Clinical Procedure (Provisional Restoration)

Selection: Choose appropriate size and shape.
Margin trimming: The margin should accommodate the height and vertical dimension of the prepared tooth.
Seat the crown: Check the margins and occlusal contacts.
Smoothing: Smooth the margins of the crown with stone burs.
Cementing: Cement the crown onto the abutment using zinc oxide eugenol based temporary cements.

Celluloid Crown Forms

Primarily used for anterior teeth, but can be used for posterior teeth.
Acts as a mold for constructing the temporary restoration.
Procedure: Coat the prepared tooth with Vaseline, create 2 holes in the corners for easier removal, trim the restoration. Fit the mold to the tooth, fill it with provisional crown material that matches the shade of the tooth. Remove excess material after it sets. Check occlusion, and polish. Temporarily cement it.

Acrylic Ready-Made Crowns

Primarily used for anterior teeth in various shades and sizes.
The procedure is similar to aluminum crown placement.

Custom Made Provisional Restorations

Direct Impression Method:
- Pre-operative impression taken with alginate or silicone rubber.
- Prepare the tooth with separation medium.
- Mix the provisional crown/bridge acrylic material and place in the tray over the prepared tooth.
Indirect Method:
- Multiple impressions (pre- and post-operative).
- A stone cast is created to repeat the direct method for the indirect restoration.
- No heat or monomers are used for the tooth. (Indirect method is better in terms of margins, and less chair time)

Provisional Bridge

When a bridge is needed, a provisional bridge is created rather than individual crowns.
The provisional bridge has to follow the same design of the final bridge.

Provisional Post Crown Technique

Pre-formed: Ready-made crowns with posts that fit into the prepared tooth
Custom-made: Acrylic crowns are placed over posts that are put into the prepared tooth's canal. The crown is then cemented in place.

Temporary Cement

A variety of temporary cements are available, most commonly based on zinc oxide and eugenol.

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Description

Test your knowledge on provisional restorations and the types of ready-made crowns used in dentistry. Understand the requirements for effective temporary restorations and their importance in patient care. Learn about different materials and their applications in dental practices.