Fundamentals of RPD Design

Question 1

which kennedy classification cannot have a modification space?

Answer 1

four

Question 2

tooth tissue supported (2)

Answer 2

kennedy class 1
kennedy class 2

Question 3

tooth supported (2)

Answer 3

kennedy class 3
kennedy class 4 (single edentulous area crossing the midline)

Question 4

whats next (4)

Answer 4

survey the cast and draw/carve orientation (tripod) lines
draw heights of contour
evaluate possible guide planes
identify undercuts

Question 5

what is opposing (2)

Answer 5

natural teeth or denture
super erupted teeth

Question 6

lets take this info and make an RPD (6)

Answer 6

Major Connectors
* Minor Connectors
* Rests
* Retentive Clasps
* Reciprocal clasps/plates
* Indirect retainers

Question 7

mandibular RPD major connectors (2)

Answer 7

lingual plate
lingual bar

Question 8

5 reasons to lingual plate

Answer 8

• Opposing a maxillary denture
• Inadequate space for a bar (8mm needed)
• Anticipate loss of additional teeth
• Mandibular tori
• Aid in lateral and rotational stability

Question 9

maxillary major connectors (4)

Answer 9

palatal strap
AP strap
anterior palatal strap
full palatal coverage

Question 10

if the major connector is not plating the lingual surfaces of the max teeth the frame needs to be at least

Answer 10

6 mm away from the gingival margin

Question 11

minor connectors

Answer 11

portion of the RPD framework that connects the major connector to
-the clasp assembly
-indirect retainer
-denture base

Question 12

in a kennedy class 3 RPD the rests of the RPD are located….
A. Away from the edentulous area on the on the teeth adjacent to the edentulous area
B. Toward the edentulous area on the teeth adjacent to the edentulous area
C. As far away from the edentulous area as possible
D. Rest seats should not be located on the teeth next to the edentulous area.

Question 13

RPD Rests
* Need approx – mm of inter-occlusal clearance
* – the buccal/lingual width
* Edentulous area bordered by teeth on anterior and posterior
- Rests located — the edentulous space
* Free end distal extension
- Rest located — from the edentulous area

Answer 13

1.5
1/3
toward
away

Question 14

How many retentive clasps would typically be utilized in a kennedy class 1 RPD design?2
3
4
5

Question 15

Number of clasps Necessary (4)

Answer 15

1: 2 clasps
2: 3 clasps
3 & 4: 4 calsps

Question 16

of clasps =

Answer 16

kennedy class + 1 with a max of 4 clasps

Question 17

how to alter the retentiveness of a clasp? (6)

Answer 17

• Clasp length
• Clasp diameter
• Clasp taper
• ½ round or round
• Material
• Amount of undercut engaged

Question 18

retentive clasps (2)

Answer 18

infrabuldge
suprabuldge

Question 19

infrabuldge
(3)
suprabuldge
(2)

Answer 19

I bar clasp
T and 1/2 T clasp
Y clasp

cast circumferential clasp (1/2 round and round)
wrought wire (combination clasp)

Question 20

Infrabuldge clasps
advantages (2)
contraindications (3)

Answer 20

esthetic
more retentive

• Excessive soft tissue undercut
• Lack of vestibular depth (min 4 mm)
• Inability to place the terminus at the gingival 1/3

Question 21

infrabuldge clasps

Answer 21

best utilized on a sound abutment tooth adjacent to a free end edentulous area provided the tooth is tall enough and provides relief (undercut( gingival to the distal guide plate

Question 22

suprabuldge clasps
* Circumferential
* 1/2 round or round cast
* Best utilized
* ½ round -
* round -

Answer 22

Tooth supported RPDs
Tooth/Tissue supported RPDs

Question 23

Wrought Wire Clasps (Combination)


Answer 23

Best used on Tooth/Tissue Supported RPDs when the abutment tooth is compromised and an ideal guide plane is not present
THE REST SEAT IN THIS SENARIO WILL BE TOWARD THE FREE END DISTAL EXTENSION

Question 24

what if i dont have any undercut (3)

Answer 24

surveyed crown
place a divot
place a composite

Question 25

When an RPD is completely seated, what is the function of the reciprocal clasp?
A. To aid in retention by applying force from the lingual
B. To counter-balance the force applied by the retentive clasp when it is in the
designated undercut
C. It serves no purpose when fully seated

Question 26

reciprocal clasps
* The reciprocal clasp is utilized to …
* The “Action Distance of Stern” is that distance that the in which the …
- Approx –mm
* Located on all teeth that have a retentive clasp

Answer 26

counterbalance the forces applied by the retentive clasp as it passes over the height of contour
retentive clasp is reciprocated.
3-5

Question 27

which kennedy class will never have an indirect retainer?

Question 28

Indirect Retainer
* Occlusal, incisal, or cingulum
* Located on …
* Located — to the primary fulcrum line which extend through the most posterior abutments
* Resists the RPD’s tendency to move or rotate in an — direction

Answer 28

tooth-tissue supported RPDS (Class | and Il)
anterior
occlusal

Question 29

RPD IMPRESSION TECHNIQUES
* — Impressions
* — impressions
* NOTE: PDL of abutment has a vertical displacement of – mm and the gingival tissue on the residual ridge has a vertical displacement of approx – mm.

Answer 29

Static
Functional
0.25
2

Question 30

RPD impression methods (3)

Answer 30

metal stock ttray w alginate (never plastic)
custom tray, bolder mold, PVS impression
corrected (altered) cast impression
-only on mandibular kennedy class 1 or 2

Question 31

when to consider
* Mandibular distal extensions (Class | & Il)
* Extensive edentulous spans
* Any case where the periphery is distorted & needs correction (overextended ridge area
* Framework — doesn’t make contact with the ridge intraorally
* Not used in the maxilla due to major connector contact with the palate

Answer 31

tissue stop

Question 32

impression technique
framework must fit the mout hand be passive
add tray to framework
– mm wax relief

Answer 32

1

Question 33

check seating on cast and in mouth
after tray is added (2)

Answer 33

rests must be fully seated also the major connector
no resistance to seating

Question 34

check peripheries
* tray must be – mm short of the vestibular extent
* No displacement when:
-
-

Answer 34

2-3

Pulling on the cheeks and lips
Patient activates the tongue

Question 35

border molding

Answer 35

same techniques as for a complete denture

Question 36

corrected cast impression (2)

Answer 36

remove wax spacer
coat tray with adhesive

Question 37

corrected cast impression
* Use — body impression material
* Carefully load tray
-no material under rests, guide planes, major connector
* Seat with pressure ONLY
over the —, NOT on the —

Answer 37

light
rests
saddle

Question 38

no pressure over tray
will cause

Answer 38

tissue compression

Question 39

remove and inspect impression no material under — - remove excess material if present
impression detail is correct

Answer 39

rests or minor connectors

Question 40

lab steps (4)

Answer 40

• Section cast-remove extensions
• Place retentive grooves or holes in the master cast
• Ensure no contact between impression material /tray& cast
• Sticky wax framework in place against the teeth

Question 41

box the master cast with the

Answer 41

RPD framework/impression attached and pour the new edentulous ridges in yellow stone

Question 42

add — to the framework if the metal stops dont contact the cast

Answer 42

duralay tissue stops

Question 43

potential problems with the corrected cast technique (2)

Answer 43

• A framework not seated either during the impression (material under rest, plate) or when being poured will result in an RPD that won’t fit properly on teeth/tissues
  *Stone leaking over teeth during pouring makes articulation impossible