Dental Crown Preparation

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the purpose of cutting into the proximal area from both sides until a few mm of interproximal island remains?

To remove the contact with a fine needle diamond

To reduce the axial surface

To create additional retention features

To protect the neighboring tooth (correct)

What should be done to the adjacent proximal surface if it is damaged?

Use a fine girt diamond or carbide bur

Perform a non-functional cusp bevel

Cut into the proximal area from both sides

Polish with white stone, silicon stones, and prophylaxis paste (correct)

What is evaluated during the preparation step?

Only the chamfer finish line and taper

The smoothness and evenness of the chamfer finish line, taper, and transition between surfaces

The presence of undercuts and proximal clearance

All of the above (correct)

What type of bur is typically used for axial reduction?

Thin round tipped diamond bur Signup and view all the answers

What is the purpose of placing a non-functional cusp bevel?

To create additional retention features Signup and view all the answers

Why is it important to take care not to injure the adjacent tooth?

To prevent damage to the adjacent tooth Signup and view all the answers

What is the recommended speed for using a fine girt diamond or carbide bur?

Any of the above Signup and view all the answers

What should be the condition of the chamfer finish line?

Smooth and glassy Signup and view all the answers

What is the recommended reduction for the incisal edge to allow for translucency in the final restoration?

2mm Signup and view all the answers

Why is less reduction required for posterior teeth?

Because esthetic is not critical Signup and view all the answers

How many imaginary parts is the facial surface divided into?

1/3 and 2/3 Signup and view all the answers

What is the depth of the grooves placed on the facial surface?

1.3mm Signup and view all the answers

How should the cervical grooves and reduction be angled?

Parallel to the long axis of the tooth and/or the intended path of insertion Signup and view all the answers

What is the purpose of the incisal portion following the facial contour?

To provide space for porcelain layering Signup and view all the answers

Where is the shoulder FL typically placed?

1 mm above the gingival crest Signup and view all the answers

What is the purpose of using a retraction cord during finishing?

To retract the gingiva and place the FL more apically Signup and view all the answers

What is the primary purpose of proper manipulation of the gingival tissue in metal-ceramic crown preparation?

To prevent gingival recession and exposure of the metal collar Signup and view all the answers

What is the recommended width of the chamfer finish line in metal-ceramic crown preparation?

0.5 mm Signup and view all the answers

What is the purpose of guiding grooves in anterior teeth preparation for metal-ceramic crowns?

To guide the bur during preparation Signup and view all the answers

What is the primary function of the interproximal margin in metal-ceramic crown preparation?

To follow the gingival contour Signup and view all the answers

What is the recommended tool for reducing the lingual surface of anterior teeth in metal-ceramic crown preparation?

Football-shaped diamond bur Signup and view all the answers

What is the primary purpose of the shoulder finish line in metal-ceramic crown preparation?

To extend well into the proximal embrasures Signup and view all the answers

What is the recommended depth of concavity removal in metal-ceramic crown preparation?

1.0 mm Signup and view all the answers

What is the primary purpose of finishing and evaluating the reduction in metal-ceramic crown preparation?

To ensure the margin provides distinct resistance to vertical displacement of an explorer tip Signup and view all the answers

Study Notes

Axial Reduction

Remove remaining tooth structure while placing chamfer margin, reducing half of axial surface first and leaving the other as reference.
Take care not to injure adjacent tooth in interproximal area.
Use enamel lip technique: cut into proximal area from both sides until a few mm of interproximal island remains, then remove contact with a fine needle diamond.

Protecting Adjacent Tooth

If adjacent proximal surface is damaged, polish with white stone, silicon stones, and prophylaxis paste.
Apply fluoride to prevent demineralization.

Finishing

Use fine grit diamond or carbide bur for finishing, operating at reduced speed or with low speed handpiece.
Smooth internal line angles, chamfer finish line should be glassy smooth.
Add non-functional cusp bevel if necessary, and additional retention features with tapered carbide bar if needed.

Evaluation

Evaluate preparation for smooth, even, and continuous chamfer finish line.
Check for 6° taper, gradual transition between prepared surfaces, and no undercuts.
Assess occlusal and proximal clearance.

Occlusal/Incisal Reduction

Reduce incisal edge by 2mm for adequate material thickness and translucency.
Posterior teeth require less reduction (1.5mm).

Buccal/Labial Reduction

Divide facial surface into 2 imaginary parts: 1/3 cervical and 2/3 incisal.
Place 3 grooves: mesial, distal, and middle, with a depth of 1.3 mm.
Cervical grooves and reduction are parallel to the long axis of the tooth and/or the intended path of insertion.
Incisal grooves are parallel to the facial contour.

Shoulder Finish Line

Place shoulder finish line 1 mm above the gingival crest.
Retract gingiva using a retraction cord to place the finish line more apically.
Manipulate gingival tissue to prevent recession and exposure of metal collar.

Axial Reduction of Proximal and Lingual Surfaces

Remove sufficient tooth structure to provide a distinct, smooth chamfer finish line (0.5 mm in width).
Use round-end tapered diamond bur held parallel to the intended path of insertion.
Place guiding grooves on anterior teeth and remove concavity with wheel or football diamond bur.
Follow gingival contour for interproximal margin and extend lingual chamfer buccally to blend with interproximal area.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the preparation steps for a complete metal crown, including axial reduction and protection of adjacent teeth.