Dentistry RPD Surveyed Crown Flashcards

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Questions and Answers

What is a surveyed crown?

A crown used as abutments to retain an RPD.

What is a good survey line?

Path of insertion of an RPD allowing the denture to go in and out without damaging soft and hard tissue.

To provide denture retention, what do we need to create?

Desirable undercut.

What is a pre-planned or surveyed restoration?

Restorations that were planned to retain and/or support future RPD or removable overdenture. Signup and view all the answers

Match the characteristics of surveyed crowns with their descriptions:

Ideal retentive contour = Proper amount of desirable undercut Definite guiding plane = Provides predictable pathways for RPD insertion Optimum occlusal rest = Ensures stability for the denture Effective reciprocation = Aids in balance and comfort of the denture Signup and view all the answers

How do you determine which RPD abutment tooth to serve as a surveyed crown?

First identify the RPD abutment tooth, then identify whether a surveyed crown is indicated. Signup and view all the answers

Does every RPD natural abutment tooth need to be a surveyed crown?

False Signup and view all the answers

What should you do prior to preparing a tooth to be an SC?

Modify the survey line and find desirable undercuts by tilting the turntable on a surveyor. Signup and view all the answers

What is the addition method for RPD?

Preparing RPD abutment tooth by intentionally adding bonded restoration to obtain proper amount of desirable undercuts. Signup and view all the answers

What is the subtraction method for RPD?

Preparing RPD abutment tooth by intentionally removing part of the tooth structure to obtain proper undercuts. Signup and view all the answers

On a surveyed crown, what is required in the preparation where the occlusal rest seat is?

More reduction. Signup and view all the answers

Rest seat and guiding planes are prepared for what material?

Metal. Signup and view all the answers

In terms of tooth preparation for SC, what is crown ledge or shoulder?

Restores the lingual contour and provides effective reciprocation. Signup and view all the answers

When writing a lab prescription for an SC, what should you specify?

Be specific about wanting a surveyed crown with a specific RPD design, survey your cast, and attach your RPD design. Signup and view all the answers

What can a laboratory technician follow your prescription to fabricate an SC that has?

More ideal retentive contour, definite guiding plane, optimum occlusal rest, effective reciprocation. Signup and view all the answers

Why should extra consideration be made when an SC is fabricated on an endodontically treated tooth?

Because the success rate of ETT used as an abutment for RPD is 77.4%. Signup and view all the answers

Why is the amount of existing coronal tooth structure an important consideration for SC?

It affects crown retention due to extra force from RPD retainers. Signup and view all the answers

A distal extension RPD with an ETT should have frequent what?

Follow-up and reline. Signup and view all the answers

The longer the RPD, the more what?

Torque on the surveyed crown. Signup and view all the answers

What is important to do when the SC comes back from the lab?

Verify that it is what you asked for prior to cementing it. Signup and view all the answers

Study Notes

Surveyed Crown Overview

A surveyed crown serves as an abutment specifically designed to retain a removable partial denture (RPD).
It is critical to establish a good survey line, which is the path of insertion allowing for smooth placement and removal of the RPD without causing tissue damage.

RPD Retention Mechanisms

Achieving denture retention requires the creation of a desirable undercut on the abutment tooth.
Restorations should ideally be pre-planned to support future RPD or removable overdentures, which may include full contour restoration or a metal substructure.

Characteristics of Surveyed Crowns

Surveyed crowns feature ideal retentive contours, definite guiding planes, optimum occlusal rests, and effective reciprocation.

Selection and Preparation of Abutment Teeth

To determine which tooth to use as a surveyed crown (SC), first, identify the RPD abutment tooth and assess the necessity of an SC.
Not every natural abutment tooth requires preparation as a SC; modifications to reduce tooth damage should be considered first.

Modifying Survey Lines

Prior to preparing a tooth as an SC, modify the survey line and explore for favorable undercuts. Options include:
- Addition method: Intentionally adding bonded materials to enhance undercut.
- Subtraction method: Intentionally removing part of the tooth structure to create a desirable undercut.

Tooth Preparation and Material Considerations

Additional occlusal reduction may be needed at the occlusal rest seat of a surveyed crown.
Rest seats and guiding planes are typically prepared for metal restorations.
A crown ledge or shoulder enhances lingual contour restoration and reciprocation effectiveness.

Laboratory Collaboration

When writing lab prescriptions for surveyed crowns, clarity is key:
- Specify desire for a surveyed crown aligned with a specific RPD design.
- Always survey and tripod the working cast.
- Include RPD design details along with the working cast.

Outcomes from Laboratory Work

A well-fabricated surveyed crown will provide an ideal retentive contour, definite guiding plane, optimal occlusal rest, and effective reciprocation.

Special Considerations for Endodontically Treated Teeth

Extra consideration is given when fabricating surveyed crowns on endodontically treated teeth, which have a reported success rate of 77.4%.
The coronal structure of the tooth is vital for crown retention, as RPD retainers exert additional forces.

Follow-Up and Maintenance

Distal extension RPDs with an SC on endodontically treated teeth should be followed up regularly and relined as needed.
A longer RPD increases torque applied to the surveyed crowns.

Final Verification

It is essential to verify that the SC delivered from the lab matches the prescribed specifications before cementation, as discrepancies may necessitate crown removal.

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Description

Test your knowledge on surveyed crowns and their application in removable partial dentures (RPD). This quiz covers key concepts such as survey lines and denture retention. Perfect for dental students and professionals looking to reinforce their understanding.