RPD - Mouth Preparations (Quiz 4)

When considering surgical preparations before a RPD, what are all of the INDICATIONS for extractions?

- Periodontally hopeless teeth

- Residual roots

- Detrimental to design or RPD

- Impacted teeth

What are three treatment options for severely malposed or extruded teeth?

- Extraction

- Orthodontic correction

- Dentoalvoeolar segment osteotomy

Besides teeth, what might also need surgical preparations? (7)

- Enlarged tuberosities

- Bony exostoses or tori

- Displaceable soft tissue

- Muscle attachment and freni

- Bony spindles and knife-edge ridges

- Ridge augmentation

- Implants

In designing a maxillary removable partial denture framework for a patient with an enlarged tuberosity, what is the minimum recommended thickness of the metal base to ensure adequate strength and rigidity?

1mm

What has the following characteristics:

- Thin and friable mucosa

- Interference with path of insertion

- Can compromise the extension of denture components

Bony exostoses or tori

What has the following characteristics:

- Soft flabby ridges

- Folds of redundant tissue

- Surgical stent

Displaceable soft tissues

During surgical preparation for a removable prosthesis, what is the recommended management for bony spines and knife-edge ridges?

- Rounded

- Vestibular deepening

In surgical preparation for prosthetic treatment, implants are often placed to support what?

Overdenture abutments

All of the following is all apart of ____________ for RPD:

- Periodontal disease and plaque control (home care instructions, recall, perio tx)

- Insufficient attached gingiva (resistance of periodontium)

- Suprabony gingival pockets (exposure of more of the clinical crown, inadequate crown:root ratio)

Periodontal preparation

What procedure is used to correct minor occlusal discrepancies before removable partial denture fabrication?

Occlusal plane modification

What are two treatment options for the corrections of malposed teeth or teeth with unacceptable contour?

- Enameloplasty

- Survey crown

T/F: Splinting of natural teeth is indicated when abutment tooth's bony support is not significantly compromised

true

What are three methods of splinting natural teeth for RPD support?

- Fixed splinting with surveyed crowns

- Cast restorations

- Swing lock RPD or multiple rests

what things should you be cautious of when preparing teeth for abutment?

Exposure of dentin and therefore...

- Sensitivity

- Caries susceptibility

What are the six objectives of abutment preparation?

- Acceptable path of insertion

- Esthetics

- Comfort

- Retention

- Stability

- Support

What is the sequence for the types of abutment preparations?

1. Guiding plane

2. Height of contour adjustments

3. Retentive grooves or depressions

4. Rest seats

Define the following:

Tooth surfaces where minor connectors or guide plates will be placed

Guiding planes

How should guiding planes be prepared?

- w/ cylindrical diamond bur

- rounded smooth edges (in harmony with existing tooth contour)

- no undercuts

- faciolingually: proximal surface

What are the occlusogingival guiding plane preparation height measurements?

- Occlusal 1/3-2/3 (Height: 2-4mm)

- Flat

Where should the guiding planes be placed on the lingual surface of the tooth?

middle 1/3 of the clinical crown

For the guiding planes on the lingual surfaces for reciprocating arms, the occlusogingival height should be ____-____mm

2-4mm

Purpose of establishing guiding planes on ______ teeth:

- To establish normal width

- To reduce unsightly spaces between tipped tooth and RPD

anterior

HOC adjustments permits circumferential clasp location above the HOC. What burs do we use for this?

tapered diamonds or burs

During height of contour adjustment, what is the main purpose of eliminating sharp facioproximal and linguoproximal line angles?

To allow better adaptation and path of insertion for the prosthesis

What are 3 very common locations that receive adjustments of height of contour?

- Mesiobuccal of upper molars

- Distobuccal of premolars

- Mesiolingual of lower molars

when adjusting the height of contour, you are limited by the thickness of the enamel and should NOT make more than a ______ reduction

0.03"

ID the abutment preparation:

- Increase depth of undercut

- Proportional to retention required

- Tapered diamonds

retentive groove or depression

What is the occlusogingival height of a retentive groove preparation?

3mm

What is the mesiodinstal length of a retentive groove preparation?

4mm

What is the depth of a retentive groove preparation?

0.01" (or 0.25mm)

Additional retentive groove preparations should be parallel to the _______ & gently sloping contoured depression (no sharply defined dimple or pit

gingival margin

What bur is used to make a retentive groove preparation for the dimple of the I-bar?

#4 round bur

When preparing a retentive groove on an abutment tooth for an RPD clasp, what should the ideal contour be?

Gentle depression on the facial surface with smooth contour (retentive clasps cannot flex into and out of deep indentations)

What type of line angle do retentive grooves have?

Line angle area

For an occlusal rest seat, it should be ___mm deep at the marginal ridge

1.5mm

For an occlusal rest seat, it should be ___mm deeper at the deepest portion than initial 1.5mm

0.5mm

For an occlusal rest seat, the preparation should be ________ 90 degrees:

A. Less than

B. Equal to

C. More than

A. Less than

What bur should we use to prepare an occlusal rest seat?

- #4 or #6 round carbide

- Diamond & tapered diamond bur

What type of line angle do rest seats have?

Round line angle

How do you check the depth and inclination of an abutment preparatoion?

With wax

How can you finish and polish an abutment preparation?

With fine diamond or green stone and rubber point

For an embrasure occlusal rest seat, it should be ____-____ mm deep

1.5-2mm

For an embrasure occlusal rest seat, it should be ____-____mm wide

3-3.5mm

T/F: For an embrasure occlusal rest seat, all contours must be gently rounded & NO undercuts

true

What bur can you use to prep the crescent or inverted V-shaped cingulum rest seat?

#37 inverted cone bur

What type of line angle do cingulum rest seats have?

Round internal line angle

In preparing a cingulum rest seat for a maxillary canine, the rest should extend from where to where?

From one marginal ridge to the opposite marginal ridge

for a cingulum rest seat that is crescent or inverted V-shaped, the mesiodistal width should be ____-____mm

2.5-3mm

for a cingulum rest seat that is crescent or inverted V-shaped, the faciolingual width should be ____mm

1.5mm

for a cingulum rest seat that is crescent or inverted V-shaped, the incisogingical depth should be ____mm

1.5mm

for a cingulum rest seat that is Ledge Shaped, the axial wall should be parallel to the ______

path of insertion

for a cingulum rest seat that is Ledge Shaped, the gingival floor should be ____-____mm wide

1-1.5mm

for a cingulum rest seat that is Ledge Shaped, the prep should be made _____ 90 degrees

A. Less than

B. Equal to

C. More than

B. Equal to

What type of bur should you use for a ledge shaped cingulum rest seat?

Flat end diamond bur or tapered fissure bur

Where should the small occlusal rest seat preparation for a ball or lug rest seat be made?

junction of middle and gingival 1/3

What type of bur should you use for a ball or lug shaped cingulum rest seat?

#4 or 6 round bur

What type of cingulum rest seat is like a small occlusal rest seat and is a marginal ridge reduction?

Ball or lug rest seat

What are the 3 kinds of cingulum rest seats discussed in lecture?

- Crescent/V-shaped

- Ledge

- Ball or lug rest seat

Define the following:

Crowns that are used as abutments for RPD

survey crown

What has the following characteristics:

- More ideal retentive contour

- Definite guiding plane

- Optimum occlusal rest

- Effective reciprocation

survey crown

t/f: if a rest seat or guiding plane is placed IN the metal survey crown, additional reduction must be made in the preparation

true

In surveryed crowns, ___________ restores the lingual contour and makes a more effective reciprocation

crown ledge or shoulder

What is the arrow pointing to?

Ledge

Before trying in a surveyed crown, what features must be verified on the master cast to ensure proper RPD design?

- Tripoded path of insertion

- Guiding planes

- Undercut

- Rest seat

What are three modifications for surveyed crowns?

- Recontouring

- Polishing

- Ensure 0.01" undercut