Dentistry: Occlusal Rest Seat and Cingulum Rest Preparation

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What is the purpose of the prepared surface of the abutment tooth?

To receive a rest and provide vertical support (correct)

To direct occlusal loads to the soft tissue

To provide horizontal support for RPD

To maintain the position of the abutment tooth

What is the primary purpose of rests in an RPD?

To resist movement towards the abutment tooth

To direct occlusal loads to the soft tissue

To provide vertical support for RPD (correct)

To maintain the established occlusal relationship

What is the function of a tooth-supported RPD rest?

To direct occlusal loads to the surrounding tissue

To allow for independent movement of the RPD

To resist movement towards the soft tissue

To function similar to fixed abutment retainers (correct)

What occurs when a rest and tooth are in stable contact under occlusal loading?

The rest and tooth remain in stable contact Signup and view all the answers

What is the characteristic of a rest in an RPD?

Rigid and receiving positive support from the abutment teeth Signup and view all the answers

What is the role of remaining natural teeth in an RPD?

To resist functional forces Signup and view all the answers

What occurs as the distance from the abutment increases in an RPD with one or more distal extension bases?

The RPD becomes more tissue-supported Signup and view all the answers

What is the benefit of rests in controlling prosthesis movement?

They provide vertical support for the RPD Signup and view all the answers

What is the primary function of rests in a removable partial denture?

To prevent movement of the prosthesis in an apical direction Signup and view all the answers

What happens when rests prevent movement of the RPD in an apical direction?

The position of the retentive portion of the clasp arms is maintained in a designated relation to the tooth undercuts Signup and view all the answers

Why is it important for the retentive portion of the clasp arm to remain in contact with the tooth?

To resist vertical dislodging forces Signup and view all the answers

What is the consequence of RPD settling on the clasp arms?

The clasp arms stand away from the tooth, allowing vertical displacement Signup and view all the answers

How do implants used as rests help to maintain vertical stability of the RPD?

By preventing compression of the supporting soft tissue Signup and view all the answers

What is the function of an occlusal rest in a removable partial denture?

To transfer stress to the abutment tooth and resist movement of the prosthesis in a cervical direction Signup and view all the answers

What is the benefit of using implants as rests in a removable partial denture?

Improved support and stability of the RPD Signup and view all the answers

What is the role of the retentive portion of the clasp arm in a removable partial denture?

To resist vertical dislodging forces Signup and view all the answers

What type of material should be avoided when restoring a Class II situation?

Glass Ionomer Signup and view all the answers

What is the purpose of an Extended Occlusal Rest?

To stabilize a lone standing tooth Signup and view all the answers

What is the minimum base width of the triangle-shaped occlusal rest seat for molars and premolars?

2.5 mm Signup and view all the answers

Why is it necessary to lower the marginal ridge of the abutment tooth?

To permit sufficient bulk of metal for strength and rigidity of the rest Signup and view all the answers

What is the recommended shape of the occlusal rest seat floor?

Concave Signup and view all the answers

Why should sharp edges or line angles be avoided in the preparation?

To prevent stress concentrations Signup and view all the answers

What is the ideal angle formed by the occlusal rest and vertical minor connector?

< 90 degrees Signup and view all the answers

What is the purpose of the reduction of the marginal ridge?

To permit sufficient bulk of metal for strength and rigidity of the rest Signup and view all the answers

When the angle between the occlusal rest and the vertical axis of the abutment tooth is more than 90 degrees, what happens?

Orthodontic-like forces are applied to the inclined plane of the abutment Signup and view all the answers

What is the recommended labio-lingual width of the rest seat at the marginal ridge?

2.5 mm Signup and view all the answers

What is the purpose of an extended occlusal rest seat in a Kennedy Class II Mod 1 and Kennedy Class III?

To minimize further tipping of the abutment and ensure forces are directed down the long axis of the abutment Signup and view all the answers

What is the minimum recommended thickness of metal for the rest seat?

1 mm Signup and view all the answers

What is the recommended width of the rest seat buccolingually in an extended occlusal rest?

1/3 of the tooth width Signup and view all the answers

What is the purpose of a cingulum ledge in an anterior rest?

To provide a positive stop for the rest Signup and view all the answers

When dentin is exposed and sensitive in an anterior rest, what may be needed?

A composite resin restoration Signup and view all the answers

What should be avoided in the preparation of an extended occlusal rest?

Undercuts and sharp angles Signup and view all the answers

What type of rest is created in a severely tilted abutment?

Onlay form Signup and view all the answers

What is the recommended minimum extension of the rest seat in a Kennedy Class II Mod 1 and Kennedy Class III?

More than 1/2 of the mesiodistal width of the tooth Signup and view all the answers