RPD Lecture 3

Question 1

what are the 2 types of direct retainers?

Answer 1

extracoronal and intracoronal

Question 2

what kind of attachment is commonly used?

Answer 2

extracoronoal attachment

Question 3

_____ retainer: precision attachment. Prefabricated keys (in PRDP) and keyways (in abutment crown) with vertical parallel walls create frictional contact which limits the movements and resists displacement

Answer 3

intracoronal

Question 4

How are the keyways of intracoronal retainers cast?

Answer 4

within the crown

Question 5

what kind of contact do the vertical parallael walls create in intracoronal retainer?

Answer 5

frictional contact.

Question 6

resistance to VERTICAL displacement?

Answer 6

retention

Question 7

areas ___ the the heigh of contour are used for the placement of flexible (terminal third) retentive clasp components

Answer 7

apical for retention

Question 8

resistance to HORIZONTAL forces applied to a tooth by an active retentive clasp during PRDP insertion and removal; counters the force of clasp deformation at the survey line.

Answer 8

reciprocation

these will be areas CORONAL to the heigh of contour and are for stabilizing (non retentive) reciprocating clasp components

Question 9

can you place the full cusp below the height of contour?

Answer 9

no, ideally just the termnal third because this is flexible

Question 10

resistance to horizontal components of MASTICATORY forces?

Answer 10

bracing.
MCs brace and stablaize
GPs also brace along with recirpocal clasp arms.

Question 11

prevents horizontal tooth movement away from the confines of the clasp assembly; assist in bracing.

Answer 11

adequate encriclement.

more than 180 degrees should be engaged by clasp assembly at largest circumference of tooth

Question 12

how much of the tooth should be engaged by the clasp assebmly?

Answer 12

more than 180 degrees with

Question 13

does the contact of encirclement of clasp have to be continuous?

Answer 13

NO! it can be continous or discontinous

Question 14

difference between cast circumferential clasp and bar type clasp?

Answer 14

bar type doesn’t circle around the entire tooth

Question 15

resistance to vertical seating forces, occlusal forces

Answer 15

support — rests for example

direct forces parallel to the long axis of the abutment teth

Question 16

the quality of inactivity or rest assumed by the teeth, tissues and prosthesis when a partial removable dental prosthesis is in place but NOT under masticatory pressure

Answer 16

passivity

Question 17

where should the retentive arm be placed?

Answer 17

gingival third of the abutment tooth in a predetermined undercut of .01

Question 18

where should the reciprocating arm be placed?

Answer 18

occlusal 1/3 of the abutment tooth

Question 19

describe the properties of the retentive arms?

Answer 19

retention= the resistance to deformation of the retentive clasp tip when in undercut.
terminal 1/3 of clasp arm is in undercut area of tooth

Question 20

what happens to the clasp tip as you insert and remove?

Answer 20

it flexes upon insertion and removal as it passes over survey line

Question 21

what kind of alloy do you want of retentive arms?

Answer 21

elastic moduli

Question 22

should recricprcal or retentive arm contact tooth first?

Answer 22

reciprocal arm should contact first.

Question 23

what is the classic supra bulge clasp?

Answer 23

Cast circumferential clasp- it’s half round in X section (low flexibility).
classic supra bulge clasp.

Question 24

other names for the C clasp?

Answer 24

akers, and circlet

Question 25

Does the reciprocal arm cross the survey line with suprabluge cusp?

Answer 25

no

Question 26

where does the retentive arm of a suprablulge cusp originate?

Answer 26

from the MC of the abutment tooth and crosses the height of contour, extending into a .01 tooth undercut

Question 27

two circumferetnail clasp assemblies originating for a common MC

Answer 27

embrasure clasp

Question 28

when do you use embrasure clasps?

Answer 28

Kennedy class II or III with no modificaiton spaces on the opposite side of arch to aid in clasping

Question 29

how many retentive arms for embrasure clasp?

Answer 29

2 retentive, 2 reciprocal, 2 rests. very aggressive tooth preparation.

Question 30

does the infra bulge clasp cross the height of contour when PRD fully seated?

Answer 30

NO?
BAR CLASP
I bar, modified T bar,
survey line is only crossed during insertion and removal

Question 31

this clasp approaches the coronal portion of the tooth from an apical position and does not cross the height of contour when fully seated?

Answer 31

infrabulge clasp

Question 32

where is the retentive clasp for I bar clasp?

Answer 32

ALWAAYS on facial????

MC/mesial rest and the distal guide plane are the reciprocating elements

Question 33

what kind of support for Kennedy class III?

Answer 33

tooth borne is the biggie!

cast circumferential is the workhorse

Question 34

what is the # of clasps rule of thumb?

Answer 34

KCLASS + 1 = number of clasps.

Question 35

what kind of clasps can we use for Kennedy Class III?

Answer 35

C clasps or bar type

Question 36

support for class IV is mostly what?

Answer 36

tooth borne

Question 37

what is an exception to the K + 1 rule?

Answer 37

kennedy class IV