s10-final-Removal Techniques for Crowns and Bridges

Question 1

What are common scenarios requiring crown or bridge removal?

Answer 1

• Faulty cementation,
• need for remake/repair,
• after temporary cementation period,
• removal of provisional restorations.

Question 2

Why might a permanently cemented restoration need removal?

Answer 2

Due to defects, decay underneath, or faulty cementation.

Question 3

When is removal of a provisional restoration necessary?

Answer 3

After the temporary cementation period or if it becomes loose/damaged.

Question 4

What indicates the need for a restoration remake?

Answer 4

Poor fit, recurrent decay, or aesthetic failure.

Question 5

What structures are at risk during crown/bridge removal?

Answer 5

Prepared abutment teeth and surrounding soft tissues.

Question 6

Why is periodontal health a consideration during removal?

Answer 6

Periodontally involved teeth risk unintended extraction.

Question 7

What damage can occur to the abutment tooth during removal?

Answer 7

Fracture of core material, porcelain margins, or the tooth itself.

Question 8

Why is axial force direction critical during removal?

Answer 8

To avoid damaging the abutment or surrounding tissues.

Question 9

What must patients be informed about before attempting intact removal?

Answer 9

Risks of failure and potential need for destructive methods.

Question 10

What tool is safest for removing a temporarily cemented ceramic crown?

Answer 10

Crown tractor with silicone inserts and non-slip powder.

Question 11

How does a crown tractor adjust to different jaws?

Answer 11

Via an adjusting screw and spring for secure fit.

Question 12

What is a primary advantage of using a hand instrument for temporary removal?

Answer 12

Minimal trauma if used carefully on loose restorations.

Question 13

When should a crown tractor not be used?

Answer 13

On permanently cemented or periodontally compromised restorations.

Question 14

How does a manual crown remover apply force?

Answer 14

Sliding a weight along a hammer shaft to deliver taps.

Question 15

What is a key drawback of manual crown removers?

Answer 15

Risk of fracturing core material or porcelain margins.

Question 16

How does a spring-activated remover work?

Answer 16

Compressing and releasing a spring to generate impact.

Question 17

What safety feature is critical for pneumatic removers?

Answer 17

Low-impact, repeated forces to break cement seal.

Question 18

Why are manual removers risky on periodontally involved teeth?

Answer 18

High risk of unintended extraction.

Question 19

What CORONAflex component is used for molar crowns?

Answer 19

Forceps.

Question 20

How are loops used in CORONAflex?

Answer 20

Threaded under the bridge near the anchor tooth, connected to a loop holder.

Question 21

What material is used with CORONAflex clamps?

Answer 21

Autopolymerized resin (e.g., Duralay or composite).

Question 22

What is the purpose of the loop holder in CORONAflex?

Answer 22

To apply axial pressure and trigger impact impulses.

Question 23

What material is used in the Richwil technique?

Answer 23

Thermoplastic adhesive resin tablets.

Question 24

How is the resin tablet applied in the Richwil method?

Answer 24

Softened in hot water, placed inter-occlusally, bitten until compressed, then cooled.

Question 25

What is the success rate for temporarily cemented crowns with Richwil?

Answer 25

1

Question 26

Which laser is used to debond ceramic veneers?

Answer 26

Erbium laser at 2780-2940 nm for less than 2 minutes.

Question 27

Why can’t lasers remove metal-ceramic or zirconia crowns?

Answer 27

Laser energy is absorbed by water in resin, not by metal/zirconia.

Question 28

What happens to the luting agent during laser removal?

Answer 28

Thermal softening due to water absorption in the resin.

Question 29

What is the first step in the WAMKEY technique?

Answer 29

Creating a small window/tunnel in the crown’s occlusal surface.

Question 30

How does WAMKEY reduce trauma to the periodontal ligament?

Answer 30

Applies pressure (not traction) to avoid ligament stress.

Question 31

Why is WAMKEY preferred for reusing crowns?

Answer 31

Causes minimal damage, allowing temporary re-cementation.

Question 32

What tool is used to section metal-ceramic crowns?

Answer 32

Diamond bur for porcelain, tungsten carbide bur for metal.

Question 33

Why is sectioning lithium disilicate crowns challenging?

Answer 33

Strong adhesion makes it time-consuming even with fine diamonds.

Question 34

What bur type is required for zirconia crown removal?

Answer 34

Densely packed fine-particle diamond burs.

Question 35

What is the main drawback of destructive techniques?

Answer 35

The crown becomes unusable after removal.

Question 36

When should sectioning be prioritized?

Answer 36

For periodontally compromised or grossly decayed abutments.

Question 37

What method is ideal for removing a fixed partial denture?

Answer 37

Pneumatic crown remover.

Question 38

Which method is contraindicated for periodontally involved teeth?

Answer 38

Manual crown removers (risk of extraction).

Question 39

What is the first step in removing threaded posts?

Answer 39

Remove the core material to expose the post.

Question 40

How is a cast post removed using the PRS kit?

Answer 40

Trephine drills around the post, followed by CCW tubular tap engagement.

Question 41

What component in the PRS kit protects the tooth during post removal?

Answer 41

Rubber bumpers seated against the occlusal surface.

Question 42

How are fiber posts removed?

Answer 42

Ultrasonic tips for composite, followed by micro burs.

Question 43

Why is temperature control critical during fiber post removal?

Answer 43

To prevent overheating and damage to the root canal.

Question 44

What are contraindications for the Richwil method?

Answer 44

Fixed bridges, missing opposing teeth, periodontally involved teeth.

Question 45

Why can’t Richwil be used for fixed bridges?

Answer 45

Lack of opposing teeth to compress the resin tablet.

Question 46

What is a limitation of laser removal for veneers?

Answer 46

Only effective for resin-bonded ceramics, not metal/zirconia.

Question 47

What ensures accuracy in automatic crown removers?

Answer 47

Controlled direction of force and reduced operator error.

Question 48

How does the Coronaflex loop holder generate force?

Answer 48

Axial pressure and impact impulses triggered by the clinician.

Question 49

What is the final step after debonding a veneer with a laser?

Answer 49

Mechanical removal with a curette or crown remover.

Question 50

Why is axial alignment crucial during crown removal?

Answer 50

Prevents uneven force that could fracture the abutment tooth.