RESTS AND REST SEATS, Direct And Indirect

Question 1

_____ support must be provided for a removable partial denture.

Answer 1

Vertical

Question 2

Any components of a partial denture on the tooth surface that provides vertical support is called a?

Answer 2

REST

Question 3

T/F

Rests Should always be located on a properly prepared tooth surface.

Answer 3

T

Question 4

The prepared surface of an abutment to receive the rest is called a?

Answer 4

“REST SEAT”.

Question 5

In short rests serves as (4)

Answer 5

to support the position of a partial denture

to resist movement towards the tissue

to transmit vertical forces to the abutment teeth

to direct those forces along the axis of the teeth.

Question 6

KENNEDY CLASS III, Modification 1, maxillary arch with rest seats prepared on the lingual surface of the canine and lateral incisor and on the occlusal surfaces of the premolar and molar.

the outline form of an occlusal rest is ______ shape with apex towards the center of the occlusal surface.

Answer 6

ROUNDED TRIANGULAR

Question 7

KENNEDY CLASS III, Modification 1, maxillary arch with rest seats prepared on the lingual surface of the canine and lateral incisor and on the occlusal surfaces of the premolar and molar.

It should be as long as it is wide, the base of the triangular shape (at the marginal ridge) should be at least _____ mm for both molar and premolars

Answer 7

2.5

Question 8

T/F

KENNEDY CLASS III, Modification 1, maxillary arch with rest seats prepared on the lingual surface of the canine and lateral incisor and on the occlusal surfaces of the premolar and molar.

Rest seats of smaller dimensions do not provide an adequate bulk for rest.

Answer 8

T

Question 9

KENNEDY CLASS III, Modification 1, maxillary arch with rest seats prepared on the lingual surface of the canine and lateral incisor and on the occlusal surfaces of the premolar and molar.

The marginal ridge of the abutment tooth at the site of the rest seat must be _____ to the abutment tooth at the site of the rest seat must be lowered to permit a sufficient bulk of metal for strength ad rigidity.

o Reduction of the marginal ridge of approximately ____ mm is usually necessary.

Answer 9

lowered

1.5

Question 10

KENNEDY CLASS III, Modification 1, maxillary arch with rest seats prepared on the lingual surface of the canine and lateral incisor and on the occlusal surfaces of the premolar and molar.

The floor of the occlusal rest seat should be ___ to the marginal ridge

Answer 10

apical

Question 11

KENNEDY CLASS III, Modification 1, maxillary arch with rest seats prepared on the lingual surface of the canine and lateral incisor and on the occlusal surfaces of the premolar and molar.

The occlusal surface should also be ____ shaped or ____.

Answer 11

spoon

concave

Question 12

KENNEDY CLASS III, Modification 1, maxillary arch with rest seats prepared on the lingual surface of the canine and lateral incisor and on the occlusal surfaces of the premolar and molar.

The angle formed by the occlusal rest and vertical minor connector from which it originates should be _____

A degree _____ fails to transmit occlusal forces along the supporting vertical axis of the abutment tooth.

Answer 12

less than 90

more than 90 °

Question 13

The floor of the occlusal rest should be inclined _____ from the lowered marginal ridge. Any angle less than 90 degree is acceptable as long as the preparation of the proximal surface and lowering and rounding of the marginal ridge precede completion of the rest seat itself

Answer 13

apically

Question 14

T/F

A lingual rest is preferable than incisal rest because it is placed close to the horizontal axis of rotation of the abutment and therefore has less tendency to tip the tooth.

Answer 14

T

Question 15

T/F

Lingual rests are more esthetically acceptable than incisal rests

Answer 15

T

Question 16

T/F

In LINGUAL REST ON CANINES AND INCISOR TEETH

If an anterior tooth is lingually slope rather than perpendicular line the lingual rest if sometimes placed at the cingulum or just incisally to the cingulum.

Answer 16

T

Question 17

T/ F

In LINGUAL REST ON CANINES AND INCISOR TEETH
Is Usually confined to maxillary canines that have gradual lingual incline and a prominent cingulum

Answer 17

T

Question 18

In LINGUAL REST ON CANINES AND INCISOR TEETH

A _____-like shape which provides a positive rest seat located favorably in relation to the long axis of the tooth is formed.

Answer 18

saddle

Question 19

The lingual rest may be placed on the surface of a [6]

Answer 19

1. Cast veneer crown.
2. A three-quarter crown.
3. Inlay
4. Laminate veneer
5. Composite restoration
6. Etched metal restoration

Question 20

it is least desirable placement of rest seats previously mentioned, it may be used successfully for selected patients when the abutment is sound and when a cast restoration is not otherwise indicated.

Answer 20

INCISAL REST & REST SEATS

Question 21

Used predominantly as auxiliary rest or as an indirect retainer.

Answer 21

INCISAL REST & REST SEATS

Question 22

It is applicable to mandibular canine; only applicable to mandibular teeth.

Answer 22

INCISAL REST & REST SEATS

Question 23

It is applicable to mandibular canine; only applicable to mandibular teeth.

Answer 23

INCISAL REST & REST SEATS

Question 24

Esthetically it is preferable to the three-quarter crown.

Answer 24

mandibular canine (INCISAL REST & REST SEATS)

Question 25

T/F Incisal rest is more likely to lead to some orthodontic movement of the tooth because of unfavorable leverage factor than is a lingual rest.

Answer 25

T

Question 26

An incisal rest is prepared in the form of a ___ ____ at the incisal edge of an incisor.

Answer 26

rounded notch

Question 27

In INCISAL REST & REST SEATS The notch should be ___ both labially and lingually

Answer 27

beveled

Question 28

An incisal rest should be approximately ____ mm wide & ____ mm deep.

Answer 28

2.5 mm wide 1.5 mm deep

Question 29

T/F The incisal rest should be under contoured slightly to allow labial and incisal finishing to the adjoining enamel.

Answer 29

FALSE The incisal rest should be OVER contoured slightly to allow labial and incisal finishing to the adjoining enamel.

Question 30

What are DIRECT RETAINERS? (2)

Answer 30

INTRACORONAL RETAINER EXTRACORONAL RETAINER

Question 31

is that quality of a removable partial denture which resists the forces of gravity, the adhesiveness of foods, and the forces associated with opening the jaws.

Answer 31

Retention

Question 32

that component of a removable partial denture used to retain and prevent dislodgement, consists of a clasp assembly or precision attachment.

Answer 32

Direct Retainer

Question 33

retention obtained in a removable partial denture by the use of clasps or attachments that resist removal from the abutment teeth

Answer 33

Direct Retention

Question 34

retention obtained in a removable partial denture by the use of clasps or attachments that resist removal from the abutment teeth

Answer 34

Direct Retention

Question 35

may be cast or may be attached totally within the restored natural contours of an abutment tooth. A. INTRACORONAL RETAINER B. EXTRACORONAL RETAINER

Answer 35

A

Question 36

typically composed of a prefabricated machined key and keyway with opposing vertical parallel walls. A. INTRACORONAL RETAINER B. EXTRACORONAL RETAINER

Answer 36

A

Question 37

usually regarded as an internal, precision attachment. A. INTRACORONAL RETAINER B. EXTRACORONAL RETAINER

Answer 37

A

Question 38

also known as clasp-type A. INTRACORONAL RETAINER B. EXTRACORONAL RETAINER

Answer 38

B

Question 39

most commonly used retainer for RPD A. INTRACORONAL RETAINER B. EXTRACORONAL RETAINER

Answer 39

B

Question 40

mechanical resistance to displacement through components placed on or attached to the external surfaces of an abutment tooth.

Answer 40

EXTRACORONAL RETAINER

Question 41

DIRECT RETAINERS ARE COMPOSED OF:

Answer 41

1. Minor Connectors 2. Rest 3. Retentive Arm 4. Non-Retentive Arm/Reciprocating Arm 5. Occlusal Rest

Question 42

from which clasp components originate

Answer 42

Minor Connectors

Question 43

designed to direct stress along the long axis of the tooth.

Answer 43

Rest

Question 44

should engage a tooth undercut. For most clasps, the retentive region is only at its terminus.

Answer 44

Retentive Arm

Question 45

should be present on the opposite side of the tooth for stabilization and reciprocation against horizontal movement of the prosthesis (rigidity of clasp arm is essential to it’s purpose

Answer 45

Non-Retentive Arm/Reciprocating Arm

Question 46

Function of rest and its location

Answer 46

support occlusal, lingual, incisal

Question 47

MINOR CONNECTOR - Function - Location;

Answer 47

stabilization proximal surfaces extending from a prepared marginal ridge to the junction of the middle and gingival third of abutment crown.

Question 48

CLASP ARMS - Function; - Location;

Answer 48

-Stabilization (reciprocation) & Retention -middle third of crown, gingival third of crown in measured undercut.

Question 49

REQUIREMENTS OF DIRECT RETAINERS

Answer 49

Support Reciprocity Bracing and Stability Retention Encircle more than 180 degrees. Passivity

Question 50

T/f Rests prevent clasp from being displaced in gingival direction.

Answer 50

T

Question 51

Bracing arms, minor connectors

Answer 51

Reciprocity

Question 52

- resists horizontal movement - Rest, minor connectors , bracing arms

Answer 52

Bracing and Stability

Question 53

T/F passive at rest, activated only during dislodgement

Answer 53

T

Question 54

this design is most frequently used on the side of the arch where there is no edentulous space

Answer 54

Embrasure Clasp

Question 55

● occlusal rests must be used to support the embrasure portions of the clasp ● should be used with double occlusal rests.

Answer 55

Embrasure Clasp

Question 56

Indication - tilted abutments - most posterior abutments - usually mesially/ lingually tilted mandibular molars.

Answer 56

Ring Clasp

Question 57

it is used when a proximal undercut cannot be approached by undercut means

Answer 57

Ring Clasp

Question 58

should always be used with a supporting strut on the non-retentive side, with or without an auxiliary occlusal rest on the opposite marginal ridge.

Answer 58

Ring Clasp

Question 59

Design - clasp approaches undercut from edentulous area and engages undercut opposite to edentulous space.

Answer 59

Circumferential/Akers clasp

Question 60

correct form of this clasp has only one retentive clasp arm, opposed by a non-retentive reciprocal arm on the opposite side.

Answer 60

Circumferential/Akers clasp

Question 61

Indication - Tooth supported partial denture

Answer 61

Circumferential/Akers clasp

Question 62

Contraindication - They cannot be used for distal extension cases as they engage the mesiobuccal undercut.

Answer 62

Circumferential/Akers clasp

Question 63

Hairpin Clasp

Answer 63

Reverse Action Clasp

Question 64

A simple circlet clasp in which the retentive arm loops back to engage an undercut apical to the point of origin.

Answer 64

Reverse Action Clasp

Question 65

used when a distofacial undercut is present adjacent to the edentulous space

Answer 65

Reverse Action Clasp

Question 66

Consists of: - retentive arm arising from one side of the tooth

Answer 66

Half and half clasp

Question 67

- a reciprocal arm arising from the other direction on the opposite side of the tooth. - two minor connectors

Answer 67

Half and half clasp

Question 68

Indications - Usually, it is used with isolated premolars and molars bounded and free end partial dentures

Answer 68

Half and half clasp

Question 69

A circumferential clasp which extends to neighboring teeth in order to provide increased splinting and stabilizing and to engage a more favorable undercut.

Answer 69

Extended Arm Clasp

Question 70

Indication - used when the undercut on the tooth near the edentulous area is poor, while that on the adjacent tooth is suitable.

Answer 70

Extended Arm Clasp

Question 71

Advantages - The clasp has splinting action - Distributes lateral load over the two teeth.

Answer 71

Extended Arm Clasp

Question 72

Best Esthetics

Answer 72

Infrabulge Arm Clasps

Question 73

I-bar most common - minimal contact w/ tooth surface so no food accumulation - minimal show of metal - same function as other clasps

Answer 73

Infrabulge Arm Clasps

Question 74

Engages 0.01 inch undercut Provides unilateral bracing

Answer 74

Infrabulge Arm Clasps

Question 75

“Y”, “T”, modified “T” and “U” less useful.

Answer 75

Infrabulge Arm Clasps

Question 76

● modification of the ring clasp with the same advantages and apparently no disadvantages ● difficult to justify it’s use.

Answer 76

Back-action Clasp

Question 77

simply two opposing circumferential clasps joined at the terminal end of the two reciprocal arms.

Answer 77

Multiple Clasp

Question 78

used when additional retention and stabilization are needed, usually on tooth-supported partial dentures.

Answer 78

Multiple Clasp

Question 79

may be used for multiple clasping in instances in which the partial denture replaces an entire half ot the dental arch.

Answer 79

Multiple Clasp

Question 80

R- REST (always mesial) P - ________ (distal) I - ____(buccal)

Answer 80

PROXIMAL PLATE I-BAR

Question 81

During function, proximal plate and I-bar clasp move in ______ direction - disengaging tooth

Answer 81

mesiogingival

Question 82

When tissue undercuts begin from 3 mm away from the gingival margin, an ____ clasp is used no matter how deep the facial surface tissue under cut.

Answer 82

RPI

Question 83

R - REST (always_____) P - PROXIMAL PLATE (distal) A - _________ARM ( always wrought wire)

Answer 83

mesial AKER’S RETENTIVE

Question 84

this distributes more functional load to edentulous ridge.

Answer 84

R- REST (always mesial) P - PROXIMAL PLATE (distal) I - I-BAR (buccal)

Question 85

Indications: - in distal extension cases, as it provides a stress releasing action. - when tissue undercuts are not severe - when esthetic is important

Answer 85

R- REST (always mesial) P - PROXIMAL PLATE (distal) I - I-BAR (buccal)

Question 86

in distal extension RPDs present with shallow vestibule or severe tissue undercut.

Answer 86

R - REST (always mesial) P - PROXIMAL PLATE (distal) A - AKER’S RETENTIVE ARM ( always wrought wire)

Question 87

when tissue undercuts begin less than 3 mm from the gingival margin and are more than 1 mm in depth, an ____ may be used.

Answer 87

RPA