L3 components of RPD pt 2

Question 1

Direct retainer

Answer 1

Part of RPD used to retain and prevent dislodgment consisting of a clasp assembly

Question 2

Clasp assembly

Answer 2

Part of RPD that acts as a direct retainer/stabilizer for a prosthesis by partially encompassing or contacting an abutment tooth.

Question 3

What are the clasp assembly components?

Answer 3

Minor connector, retentive arm, rest, reciprocal arm.

Question 4

What are the 4 categories of clasp types?

Answer 4

1. composition
2. configuration
3. primary function
4. directional approach to undercut

Question 5

What does passivity mean?

Answer 5

There should eb no active force on the tooth when a clasp assembly is in place.

Question 6

What are the indications and disadvantages of circumferential clasp?

Answer 6

Indications: tooth borne RPD and tooth-mucosa borne RPD when the bar clasp is contraindicated

Disadvantages: more tooth coverage, more plaque retentive, less esthetic

Question 7

Bar approaches the undercut from the _______ direction .

Answer 7

gingival “bar below”

Question 8

Circumferential approaches the undercut from the ________ direction.

Answer 8

occlusal

Question 9

Clasp types bar clasp include?

Answer 9

T, I, Y

Question 10

What factors influence clasp flexibility?

Answer 10

diameter, length, type of alloy used, taper of the clasp, cross sectional form of the clasp

Question 11

Factors determining the depth of undercut engaged

Answer 11

angle of the gingival convergence, clasp flexibility, presence of tripping action, the number and location of retentive elements

Question 12

Reciprocation

Answer 12

the mechanism by which lateral forces generated by a retentive clasp passing over a HOC are counterbalanced by a reciprocal clasp passing along a reciprocal guiding plan

Question 13

RPI Clasp Assembly:

Answer 13

Rest (medial rest)
Proximal plate (distal proximal plate)
I bar

Question 14

How does RPI Clasp assembly work?

Answer 14

Rotation occurs in the area of the medial rest
I bar clasp and proximal plate disengage from the tooth during function

Forces transmitted thru the RPD components to the mesial rest directing medial torquing and axial forces tot the tooth.

Question 15

Ring class assembly

Answer 15

a single clasp army which encircles nearly the entire circumference of the tooth

• engages .020-.030 inch undercut
• unilateral bracing
• may be used for tilted molars

Question 16

Back action clasp assembly

Answer 16

• modification of the ring clasp engages 010-.0120 inch undercut
• unilateral bracing assembly
• may be used for premolars

Question 17

Circumferential “C” Clasp assembly

Answer 17

• cast circumferential bracing clasp
• engages .010-.020 inch undercut
• bilateral bracing
• may be used when a distofacial undercut exists

Question 18

RII
Rest
I bar retentive clasp
I bar bracing clasp

Answer 18

• engages .010 inch undercut

- unilateral bracing

Question 19

If there is a soft tissue undercut what type of clasp assembly is contraindicated?

Answer 19

Bar clasp