prosthodontics

Question 1

what is the vibrating line?

Answer 1

junction between the hard palate and soft palate

Question 2

what is the occlusal plane?

Answer 2

horizontal surface occupied by upper teeth
extends from tip of mesioincisal edge of upper central incisor to of mesiobuccal cusp of upper 1st molar on each side

Question 3

what is the neutral zone?

Answer 3

specific area where the function of musculature will not unseat the denture
where forces generated by tongue are neutralised by forces generated by lips and cheeks

Question 4

how is denture stability achieved?

Answer 4

make sure peripheries of denture are extended to the right depth
by making sure occlusion is balanced

Question 5

what is the occlusal rim?

Answer 5

a wax structure with occluding surfaces attached to denture base

Question 6

what is an occlusal rim used for?

Answer 6

recording relation of maxilla to mandible
positioning of the teeth

Question 7

what features should be present on maxillary definitive impressions?

Answer 7

tuberosity
hamular notch
extension anterior to vibrating line for post dam
functional depth and width of sulcus

Question 8

what features should be present on a mandibular definitive impression?

Answer 8

coverage of pear-shaped pad and buccal shelf
retro-molar pad and extension into lingual pouch
functional width and depth of sulcus
ensure area of primary support of buccal shelf and retromolar pad

Question 9

where should a maxillary denture sit in order to create a good posterior seal?

Answer 9

at level of hamular notch
located between distal surface of tuberosity and hamular process of medial pterygoid plate of maxilla

Question 10

describe use of impression compound for primary impressions

Answer 10

non-elastic material which records poorer surface detail
expensive and can be messy
good for primary due to high mucocompressive viscosity

Question 11

describe the use of alginate for primary impressions

Answer 11

elastic material- will flow into undercuts
can record surface detail for primarys

Question 12

describe the use of silicone for master impressions

Answer 12

dimensionally stable
can be made into a variety of consistencies which means it accurately records surface detail

Question 13

describe the use of polyether/impregum for master impressions

Answer 13

dimensionally stable
can be made into variety of consistencies which means it accurately records surface detail

Question 14

describe the use of alginate for master impressions

Answer 14

elastic- can flow into undercuts if they are present

Question 15

what is the purpose of stops to the space prescribed in the canine and post dam regions of upper trays?

Answer 15

to allow correction of posterior borders of trays and will perform space for impression material

Question 16

where should stops be placed to the space provided on lower trays in order to allow preformed space for impression material?

Answer 16

retromolar pad
ridge of canine areas

Question 17

why is silicone not used for primary inpressions?

Answer 17

dimensionally stable and hydrophobic- can cause small defects and blows
very messy and technique sensitive

Question 18

what information should be recorded on to a record block?

Answer 18

the OVD
centre line
occlusal plane
high lip line
canine line
arch form

Question 19

what provides accurate fit for dentures?

Answer 19

accurate fit- as little space as possible between denture base and mucosa
border seal- extending flanges to depth of functional sulcus and incorporation of post dam

Question 20

what anatomical features help identify where the posterior border should be placed for the upper denture?

Answer 20

hamular notch
vibrating line
palatine fovea

Question 21

explain the cawood and howell classification

Answer 21

1- before extraction
2- after extraction
3- high well rounded ridge
4- knife edge shaped ridge
5- low well rounded ridge
6- depression bone level

Question 22

what is the primary support area for maxillary dentures?

Answer 22

hard palate

Question 23

what is the secondary support area for maxillary dentures?

Answer 23

ridge crest

Question 24

name areas in a maxillary denture that may require relief

Answer 24

midline suture
incisive papilla
lingual frenum

Question 25

what are the primary support areas in lower dentures?

Answer 25

buccal shelf and pear shaped pad

Question 26

what are the secondary areas of support in lower dentures?

Answer 26

ridge crest and genial tubercles

Question 27

what areas may need relief in lower dentures?

Answer 27

lingual ridge incline and mylohyoid ridge

Question 28

define 'retention'

Answer 28

the resistance to displacement forces e.g. gravity, speech and mastication

Question 29

define 'stability'

Answer 29

the ability of the denture to resist displacement by functional stresses

Question 30

what materials can be used to modify trays?

Answer 30

soft red wax green stick putty impression compound

Question 31

what should the extension of master impressions be?

Answer 31

2mm short of sulcus depth to allow border moulding

Question 32

what impression material is used for masters on replica dentures?

Answer 32

light body silicone

Question 33

what material is used to make special trays?

Answer 33

light cured acrylic resin

Question 34

define 'mucocompression'

Answer 34

pressure is applied to the mucosa so that the shape of the tissues under load is recorded

Question 35

define 'mucostasis'

Answer 35

the minimum pressure applied to the tissues to record at rest

Question 36

what are the steps of jaw registration?

Answer 36

adjust upper and lower block for retention adjust upper block for occlusal planes lower tooth position and horizontal jaw relationship measure vertical dimension and establish face height select shape and mould

Question 37

what do you asses for patient's current denture?

Answer 37

LIMBO Lip support, nasiolabial angle 90 degrees Incisal level Midline Buccal corridor- space in corners of mouth, taper towards back Occlusal plane, interpupillary line and ala-traguc line

Question 38

how do you record the bite?

Answer 38

jaw registration paste- jetbite soft wax and patient bites onto it

Question 39

what is the role of mould liners?

Answer 39

reduce porisity easier for deflasking to be carried out

Question 40

name the stages of complete denture design

Answer 40

primary impressions primary casts and special trays master impressions master casts and record blocks jaw registration mount casts and set up try in finish denture denture delivery review

Question 41

what are the laboratory stages of complete dentures?

Answer 41

primary casts and special trays master casts and record blocks mount casts and set up process/finish denture

Question 42

what are the transfer lines used when making dentures?

Answer 42

high smile line centre line canine line residual alveolar line alveolar contour line rim profile

Question 43

why do we mark the residual alveolar line?

Answer 43

so that the teeth are set in such a way above the the lower residual ridges that the contacts are on this line

Question 44

why do we mark the alveolar contour line?

Answer 44

if the teeth are set on a slope then the denture may be displaced during function

Question 45

what would you write in master impression stage of a complete denture lab sheet?

Answer 45

please pour cast of primary impression in 50:50 plaster/stone construct upper and lower custom trays in light cured PMMA, non-perforated with upper 2mm spacing and lower 1mm spacing , intra oral handles and finger stops

Question 46

what would you write in jaw registration stage of a complete denture lab sheet?

Answer 46

please pour casts of master impressions in 100% dental stone and construct wax rims for jaw registration. return rims on casts

Question 47

what would you write in tooth trail stage of a complete denture lab sheet?

Answer 47

please mount casts in registration and set teeth for wax trial return wax trial dentures on mounted casts

Question 48

what would you write in delivery stage of a complete denture lab sheet?

Answer 48

please finish denture in heat cured PMMA and return on casts

Question 49

what are the stages of denture delivery?

Answer 49

feel for lumps/bumps with gloved finger remove any excess acrylic with acrylic bur in straight hand piece check fit, retention, stability, aesthetics, speech, occlusal contacts ask pt what they think

Question 50

what instructions do you give to the pt when delivering a denture?

Answer 50

may take a while to get used to- if uncomfortable just wear for a few hours per day may cause increased salivation and impede speech- this will stop eventually chew on both sides of the mouth rinse denture with water after every meal clean denture twice a day remove when sleeping clean over sink with water- never use boiling water brush with toothbrush and unperfumed soap e.g. washing up liquid be careful not to distort the clasps soak in denture cleanser once daily according to manufacturers instructions avoid solutions with sodium hypochlorite e.g. milton rinse after soaking soak overnight in water use adhesives according to manufacturers instructions

Question 51

what is the purpose of surveying?

Answer 51

to determine guide planes and mark survey lines for fabrication of RPD determines undercuts

Question 52

why do we mark the high smile line?

Answer 52

to get an idea of how much tooth will show when smiling

Question 53

why do we mark the high centre line?

Answer 53

so that the midline of the patient's teeth matches their face

Question 54

why do we mark the canine line?

Answer 54

marks which tooth size should be used

Question 55

why do we mark the rim profile?

Answer 55

to ensure adequate lip support

Question 56

How long do you steep cobalt chrome dentures for

Answer 56

no more than 10 minutes or they will corrode