partial dentures system of design

Question 1

what are some alternative treatments to partial dentures

Answer 1

• no active treatment
• fixed prosthesis, either conventional or resin bonded
• implant retained prosthesis

Question 2

why is it important for the clinicians to be the one to design the denture

Answer 2

we have seen the patient, know their story and what they expect
condition of the teeth, oral health
we have assessed current dentures and occlusion
have a more complete understanding of alternatives and can give clear cost information

Question 3

what are the key principles to partial denture design

Answer 3

replace lost tissue and teeth, restore function, speech and aesthetics
minimise damage to adjacent teeth, restorations and tissues
designed with periodontal health in mind

Question 4

what is the systematic approach to denture design

Answer 4

0 - case assessment
1 - classification of support for each saddle
2a - choose the denture base material
2b - connect saddles together
3 - choose the path of insertion and delineate undercuts
4 - resistant of movement away from the teeth
5 - indirect retention
6 - resistance of movement toward the teeth and tissues
7 - resistance to horizontal movement
8 - simplification

Question 5

how are saddles connected together

Answer 5

connectors. literally.

Question 6

what is surveying

Answer 6

choose the path of insertion and delineate undercuts

Question 7

what is retention

Answer 7

resistance of movement away from the teeth

Question 8

what is support

Answer 8

resistance of movement toward the teeth and tissues

Question 9

what is bracing or reciprocation

Answer 9

resisting horizontal movement

Question 10

label the partial denture and provide a short description of their function

Answer 10

from the top down

• major connector (lingual bar) to connect the parts
• cingulum rest (support and indirect retention)
• acrylic tooth restoring natural tooth
• pink acrylic restoring lost mucosa and bone
• occlusal rest for support
• ring clasp for retention

Question 11

what is a saddle

Answer 11

an area of oral mucosa where teeth are being replaced

Question 12

how are edentulous saddles classified for partial dentures

Answer 12

Craddock classification based on how the saddle is loaded. Kennedy classification based on the location of the saddles.

Question 13

describe the craddock classifications

Answer 13

Class 1 - tooth borne
class II - mucosa borne
class III - tooth and mucosa borne
class IV - implant borne
class V - implant and mucosa borne

Question 14

describe the Kennedy classifications

Answer 14

class I - bilateral free end saddle
class II - unilateral free end saddle
class III - single bounded saddle not crossing the midline
class IV - single bounded saddle crossing the midline

Question 15

Answer 15

Kennedy class I

Question 16

Answer 16

Kennedy class 2

Question 17

Answer 17

Kennedy class III

Question 18

Answer 18

Kennedy class IV

Question 19

what is the difference between Kennedy class III and IV

Answer 19

III is not crossing the midline but IV does cross the midline

Question 20

which saddle should be used to define the main Kennedy classifications

Answer 20

the most posterior saddle

Question 21

what is the solution if there is more than 1 edentulous saddle

Answer 21

modifications are used to refine the basic classification, but the most posterior saddle will be used to define the main Kennedy classification

Question 22

can you have a modification for all saddle classes

Answer 22

not class IV

Question 23

what are the options for denture base material

Answer 23

acrylic
cobalt chrome
polyether ether ketone
flexible
gold

Question 24

what are the two types of connectors

Answer 24

major connectors which connect all the components
minor connectors which connect rests, clasps and bracing arms

Question 25

what are the common mandibular major connectors

Answer 25

acrylic plate, lingual bar, lingual plate

Question 26

Answer 26

acrylic plate

Question 27

Answer 27

lingual bar

Question 28

Answer 28

lingual plate

Question 29

Answer 29

mid palatal bar

Question 30

Answer 30

anterior palatal bar

Question 31

how to choose the path of insertion and delineate undercuts

Answer 31

surveying casts surveyor or digital surveying choose retentive elements path of insertion and removal of the denture

Question 32

retention means...

Answer 32

resistance of the denture to vertical displacement lifting away from the tissues

Question 33

what are some common methods of retention

Answer 33

clasps soft tissue undercuts adhesion friction path of insertion precision attachments and implants

Question 34

how is indirect retention achieved

Answer 34

by one or more indirect retainers that reduce the tendency for a denture base to move in an occlusal direction or rotate about the fulcrum line

Question 35

describe how the indirect retention occurs in this picture

Answer 35

incisal rest X transfers, but the fulcrum line AB to AC. as D rises on the new fulcrum, clasps act indirectly to resist this movement, the further C is away from AB the more effective the indirect retention will be

Question 36

what are the two methods of rests to support the partial denture

Answer 36

occlusal and cingulum rests

Question 37

what happens if there is inadequate denture support

Answer 37

It will sink into the tissues and traumatise them

Question 38

what can be done if there is insufficient occlusal space for a rest

Answer 38

prepare rest seats with a drill

Question 39

what is the horizontal movement that must be resisted in a partial denture

Answer 39

bracing of forward, backward and lateral dislodging forces

Question 40

what does reciprocation prevent

Answer 40

clasp arms moving the clasped tooth

Question 41

what do reciprocal arms do

Answer 41

prevent the tooth movement and engage the undercut

Question 42

why should partial dentures be kept simple

Answer 42

complex designs have complex failures and problems patient prefers simple meet the demands of economic viability of working within health services

Question 43

which saddle support is the least damaging

Answer 43

tooth borne

Question 44

what is a clasp

Answer 44

something resting on the tooth to reduce the tendency for the denture to move

Question 45

what are the functions of occlusal rests for partial removable denture

Answer 45

- provide vertical support for the partial denture - maintain components in their planned positions - maintain established occlusal relationships by preventing settling of the denture - prevent impingement of the soft tissues - directs and distributes occlusal loads to abutment teeth

Question 46

what shape should occlusal rests be

Answer 46

rounded triangular shape with the apex toward the centre of the occlusal surface

Question 47

why do the clasps have to cover both sides of the tooth ie wrap around it

Answer 47

the tooth would move otherwise

Question 48

basic sequence of design

Answer 48

saddles support retention bracing and reciprocation connector indirect retention review of completed design

Question 49

what does RPD design need to satisfy

Answer 49

the four principles shown to promote continued oral health - effective support - clearance of gingival margins - simplicity - rigid connector

Question 50

why is the movement potential less for a tooth supported prosthesis

Answer 50

the functional loading is provided by the teeth

Question 51

what is the residual ridge

Answer 51

remaining alveolar bone and overlying connective tissue covered with mucosa

Question 52

how are tooth supported partial dentures retained and stabilised

Answer 52

by a clasp at each edentulous space

Question 53

what is a requirement for clasps

Answer 53

they need to flex sufficiently during placement and removal of the denture to pass over the height of the contour of the teeth

Question 54

describe the pros and cons of acrylic denture bases

Answer 54

pros - affordable - easy to repair cons - likely to break and crack - stain

Question 55

describe the pros and cons of cobalt chrome denture bases

Answer 55

pros - strong and durable - lighter and thinner than acrylic so more comfortable to wear - less likely to stain - more resistant to temperature changes cons - more expensive - harder to adjust

Question 56

what are the pros of cobalt chrome partial dentures

Answer 56

- custom designed for gums and bite - can be made smaller to uncover more of the palate - help prevent neighbouring teeth from moving out of position - better for your overall oral hygiene