Dental Crowns and Restorations

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Questions and Answers

In what situations is an all-metal crown most appropriately used?

To restore incisal edges of anterior teeth

On teeth with multiple defective axial surfaces and high stress

When maximum esthetics are required

On molars and teeth with no esthetic expectations (correct)

What is a disadvantage of all-ceramic crowns compared to metal-ceramic crowns?

They are less esthetic

They provide less resistance to fracture (correct)

They are more cumbersome to fabricate

They require less tooth structure removal

Which type of crown should be used when both full coverage and a good cosmetic result are required?

All-ceramic crown

All-metal crown

Ceramic veneer

Metal-ceramic crown (correct)

What is a key reason for the interest in ceramic veneers?

They provide esthetic results without damaging intact teeth Signup and view all the answers

Which restoration is indicated for use in patients with incisal chipping and small proximal lesions?

Ceramic veneer Signup and view all the answers

Which type of crown requires the removal of large quantities of tooth structure for premolar and molar preparations?

All-ceramic crown Signup and view all the answers

What limits the use of all-ceramic crowns?

Their low fracture resistance under high stress Signup and view all the answers

Which crown type is typically not used for anterior teeth?

All-metal crown Signup and view all the answers

What is the advantage of a nonrigid fixed partial denture over a rigid design?

It allows for independent movement of abutments. Signup and view all the answers

Where is the ideal placement for the stress-breaking device in a five-unit pier-abutment restoration?

On the middle abutment. Signup and view all the answers

Which factor contributes to the tilting of posterior teeth when occlusal forces are applied?

The natural long axes of the posterior teeth leaning slightly mesially. Signup and view all the answers

What happens when the keyway of the connector is incorrectly placed on the mesial side of the distal pontic?

The key is unseated during mesial movements. Signup and view all the answers

What is a potential outcome if a mandibular molar tilts mesially?

It results in a discrepancy in long axis alignment with adjacent teeth. Signup and view all the answers

Which condition may lead to the supereruption of posterior units in a fixed partial denture setup?

When there is no occlusal force acting on posterior units. Signup and view all the answers

What contributes to the challenges of preparing abutment teeth for a fixed partial denture?

Long axis misalignment with the first molar. Signup and view all the answers

How does a rigid fixed partial denture generally behave compared to a nonrigid design?

It distributes load more evenly across the denture. Signup and view all the answers

What is the primary reason for not placing a prosthesis if the patient perceives no impairment?

To avoid unnecessary procedures Signup and view all the answers

What are the potential issues related to fixed partial dentures with a lone pier abutment?

Unpredictable tooth movement Signup and view all the answers

What does the term 'faciolingual movement' refer to?

Movement towards the facial and lingual sides of the arch Signup and view all the answers

Why is a completely rigid restoration not always recommended?

It may lead to stress concentration around abutments Signup and view all the answers

What was the range of faciolingual movement observed in studies?

56 to 108 μm Signup and view all the answers

How does the curvature of the arch affect tooth movement?

It alters the degree of movement based on tooth location Signup and view all the answers

What type of connector is preferred for fixed partial dentures to provide strength?

Rigid connectors Signup and view all the answers

What should a dentist do when encountering a patient with no movement in adjacent teeth?

Congratulate the patient on their fortune Signup and view all the answers

What complication arises due to the presence of a third molar in relation to a fixed partial denture?

The mesial surface of the tipped third molar can interfere with the path of insertion. Signup and view all the answers

What corrective measure can be taken if the third molar's encroachment is slight?

Restore or recontour the mesial surface of the third molar. Signup and view all the answers

What device is commonly used in orthodontics to achieve molar uprighting?

A fixed appliance with a helical uprighting spring. Signup and view all the answers

What is the recommended treatment for severe tilting of the second molar?

Uprighting the molar through orthodontic treatment. Signup and view all the answers

How long does the average treatment time for uprighting a molar generally take?

3 months. Signup and view all the answers

Which approach can be used to provide stability after treatment involving the second molar?

Fabricating a provisional fixed partial denture immediately after appliance removal. Signup and view all the answers

What notice must be taken when the second molar is moving distally after the removal of the third molar?

It must be grounded out of occlusion to allow further movement. Signup and view all the answers

What type of crown can be used as a retainer in a fixed partial denture specifically for tilted molars?

A proximal half crown. Signup and view all the answers

What is the maximum degree of convergence allowed for the long axis of prospective abutments in a fixed partial denture?

25 to 30 degrees Signup and view all the answers

What happens to stress in the alveolar bone of a molar that has tipped mesially when fitted with a fixed partial denture?

It experiences less stress Signup and view all the answers

When is a proximal half crown contraindicated as a retainer on the distal abutment?

If there is a high marginal ridge height discrepancy Signup and view all the answers

What is one of the key requirements for using a proximal half crown as a retainer?

The area must be kept exceptionally clean Signup and view all the answers

What is the preparation design necessary for the optical function of a telescope crown?

Full crown with heavyweight reduction Signup and view all the answers

What can happen if the nonrigid connector is placed on the mesial aspect of the tipped molar?

It could cause further tipping of the tooth Signup and view all the answers

What feature is included in the distal surface of the premolar when preparing for a nonrigid connector?

A box form for keyway accommodation Signup and view all the answers

For a nonrigid connector to be effective, what should the path of insertion of the full crown on the molar be?

Parallel to the long axis of the tilted tooth Signup and view all the answers

Study Notes

All-Metal Crown

Provides maximum retention, suitable for molars and premolars with no esthetic requirements
Requires less tooth removal compared to ceramic crowns, making it suitable for posterior fixed partial dentures

Metal-Ceramic Crown

Offers both maximum retention and high esthetic qualities
Can be used as a fixed partial denture retainer for full coverage with a good cosmetic result

All-Ceramic Crown

Best choice when maximum esthetics and full coverage are required
Not as fracture-resistant as metal-ceramic crowns, limiting their use to areas with low to moderate stress
Primarily used for incisors, but cast glass ceramics can be used for posterior teeth

Ceramic Veneer

Less destructive alternative to full crowns for esthetic restorations
Used for intact anterior teeth with staining, developmental defects, minor chipping, and small proximal lesions

Pier Abutments

A single tooth standing alone between two edentulous spaces presents a challenge for fixed partial dentures
Physiologic tooth movement and differing retentive capacities of retainers can lead to stress on the abutments in rigid five-unit fixed partial dentures
Faciolingual movement varies from 56 to 108 μm, with intrusion being 28 μm
Different tooth segments move in different directions, creating stress on the abutments in long-span prostheses

Tilted Molar Abutments

A common problem where a mandibular second molar has tilted mesially into the first molar space
Impossible to prepare abutments for a fixed partial denture along their long axes while achieving a common path of insertion
If no functional, occlusal, or esthetic impairment exists, a prosthesis may not be necessary
Orthodontic correction (uprighting) is the preferred treatment for severe tilting, using a fixed appliance with helical uprighting spring and open coil spring
Average treatment time for uprighting is 3 months
If orthodontic correction is not possible or only partially achievable, fixed partial dentures can still be made
A tilted molar will exhibit less stress in the alveolar bone with a fixed partial denture than without it
Stress on the premolar will increase

Solutions for Tilted Molar Abutments

Proximal half crown can be used as a retainer on the distal abutment, provided the distal surface is intact and the patient maintains good oral hygiene
Telescope crown and coping can be used as a retainer on the distal abutment, allowing for full coverage of the clinical crown
Nonrigid connectors can be used to compensate for the inclination of the tilted molar, placing the connector on the distal aspect of the premolar retainer

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Description

Explore the different types of dental crowns including all-metal, metal-ceramic, all-ceramic, and ceramic veneers. This quiz will test your knowledge on their applications, characteristics, and suitability for various dental situations. Perfect for dental students and professionals looking to enhance their understanding of restorative dentistry.