Theory of dentures 3

Question 1

equipment needed for trimming wax blocks

Answer 1

• Bunsen/ induction heater
• Foxen bite plane
• Wax knife
• Willis bite gauge
• palate knife or iron (handy)

Question 2

step 1 of adjusting upper wax block

Answer 2

adjust the upper wax rim to maximise retention

• Try it in, it will be bulky warn pt
  
  • It has to stay in place (fixative can be of use)
• Use the wax knife and hot plate/spatula to make adjustments
• Too much lip support and it will drop
• You may need to adjust the rim labially/buccallyAny overextension of the peripheries and it will drop - manipulate

Question 3

step 2 of adjusting the upper wax block

Answer 3

adjust the upper record blck for tooth position

• Look at previous denture
  
  • How much tooth do they show
  • What changes did you want to make
• Consider the patients age

Question 4

acronym for tooth positioning

Answer 4

LIMBO

Lip Support

Incisal Level

Midline

Buccal corridor

Occlusal plane

Question 5

Lip support and nasolabial angle

Answer 5

Approx. 90 degree correct but depends on individual

Question 6

how to determine incisal plane level

Answer 6

• Look
• “F” – fricative (lower lip touches upper lip)
• Old photos (caution)
• Variable – age; lip level

get pt involved

Question 7

steps in to aid in positioning anterior teeth

Answer 7

• Lick lips
• Relax
• Fricatives
• Trim block so showing the right height – compare with old denture, take in and out and check incisal position

Question 8

upper tooth position anteriors

Answer 8

up to 1cm anterior to incisive papilla

Question 9

upper tooth position canines

Answer 9

below nose

Question 10

incisal plane orientation determined with

Answer 10

Use fox’s bite plane

• If level with interpupillary – then true

Want incisal plane and interpupillary parallel - adjust

Question 11

2 techniques for tooth position

Answer 11

replica technique

conventional technique

Question 12

replica technique for tooth position

Answer 12

Easy – look at treatment plan (as teeth already in wax so just look for changes needed)

Question 13

conventional technique for tooth position

Answer 13

Standard values

• Journal of Oral Rehabilitation 2004 31; 554–561
• International Journal of Oral Science (2013) 5, 155–161

Question 14

what mark is this

Answer 14

high lip line

helps when selecting tooth so can consider height

Question 15

what mark is this

Answer 15

centreline

Question 16

tools to make marks in wax rims

Answer 16

wax knife or le cron carver

Question 17

how to test if centre line mark is correct

Answer 17

mirror and check from behind the pt to check it looks correct

Question 18

buccal corridor

Answer 18

difficult, subjective

Mid-canine line in relation to buccal corridor – indication of where the start of the buccal corridor is

Use floss from the tear duct of eye down to nose and mouth

Question 19

impact of buccal corridors

Answer 19

How much tooth seen in different buccal corridors

• Narrow arch with obvious buccal corridor to broad arch with small buccal corridor

https://www.realself.com/question/toronto-ks-correct-my-large-buccal-corridor-dark-spaces-the-edge-my-smile

Question 20

how to determine occlusal plane

Answer 20

alar tragal line with fox’s bite plane – want parallel, or fox’s bite plane angled up v slightly

• Remember don’t alter incisors you have done that already

Question 21

how to decide if happy with upper record block adjustments before occlusal reg?

Answer 21

Clue does it look denture shaped

Yes -> move onto lower

No -> complete upper

Question 22

3 steps in adjusting upper record block

Answer 22

Step 1: Adjust the upper record block for retention

Step 2: Adjust the upper record block for tooth position

Step 3: Adjust the upper record block for occlusal plane

Question 23

2 steps in adjusting lower record block before occlusal reg?

Answer 23

Step 4: Measure vertical dimension and establish face height

Step 5: Lower tooth position

Question 24

lower tooth position importance

Answer 24

Critical to lower denture – can be loose if tooth not in neutral zone (area with minimum force acting on denture)

Look where residual ridge is

• molar is largely lingual so denture will be unstable
• too buccal – cheek impinge

want narrow teeth right over ridge

Question 25

why do we need to adjust lower record block

Answer 25

want to adjust it so tongue helps keep denture in place rather than displace it

Question 26

neutral zone for lower tooth position is

Answer 26

area with miimum force acting on denture over ridge

Question 27

anterior lower tooth position

Answer 27

over ridge (or v slightly forward)

Question 28

posterior lower tooth postion

Answer 28

over ridge

Question 29

lower polished surface aim

Answer 29

Aim to direct forces of tongue in favour of denture stability * triangle make denture base wider than top so tongue push on denture down (unlike if flat like rectangle)

Question 30

consider relationship between upper and lower teeth when deciding postion of lower teeth

Answer 30

Anterior teeth * overbite – shallow * too deep - when protrude, dentures will rock and one will be displaced * overjet – can be Class II (large) or edge to edge Posterior teeth * Normal occlusion (push upper teeth out beyond the ridge – affect buccal corridor) * Cross bite (push upper teeth in?) *4:40* Group function often in C/C - but still getting contact of posterior teeth - imp

Question 31

resting vertical dimension and resting face height determined with

Answer 31

* Two measuring points in the midline of the face * On sites of minimal influence from muscles of facial expression * Ask patient to moisten lips and bring them into relaxed light contact * Wearing adjusted rim use willis bite gauge or dividers

Question 32

OVD determined by

Answer 32

occlusal vertical dimension (pt biting together) * Insert upper and lower record blocks * Dividers too wide if have free way space correct * Reduce the lower wax rim in height until it contacts the upper rim evenly * The OVD should be 2-4mm less than the RVD

Question 33

freeway space (FWS) =

Answer 33

RVD - OVD resting vertical dimension - occlusal vertical dimension

Question 34

freeway space ideal

Answer 34

2-4mm * Often greater with worn teeth * Don’t change too much from original denture * Avoid -ve freeway space * Always space between dentures at rest Facebow – NOT FOR COMPLETE DENTURES OVD in old dentures if protruding teeth OVD not accurate

Question 35

textbook retruded contact position

Answer 35

* The retruded contact position (RCP) is a reproducible maxillomandibular relationship in edentulous patient * Guided occlusal relationship at the most retruded position of the condyles in the joint cavities * It is used as a reference point for mounting casts on an articulator

Question 36

retruded contact position used in real life for occlusal registration

Answer 36

* Is occlusion reproducible ICP is more comfortable for pt – use if reproducible

Question 37

how to register occlusion

Answer 37

*Line at far edge – to see if where you have recorded occlusion is where expected* Knotch is blocks so when bite recording paste comes apart or loose can replace accurately

Question 38

why use recording paste rather than wax when recording occlusion

Answer 38

Once recorded wax is set – cannot break the record blocks apart so cannot try them separately back in mouth to check if occlusion recorded is automatically what they go into

Question 39

benefit of bite recording paste

Answer 39

Bite recording paste sets quickly Separate models and let pt bite with them back in (do not use - wax cannot break apart)

Question 40

articulator to prescribe for C/C when got occlusal reg

Answer 40

Generally average value articulator (hinge not enough accuracy)

Question 41

how to select anterior teeth

Answer 41

* Often come in matching moulds * Old denture – did they like?

Question 42

how to determine tooth mould size and shape (3)

Answer 42

1. Frush and Fisher * Square * Ovoid * Tapering 2. Previous dentures 3. Photos (take care)

Question 43

numbers of tooth moulds indicate

Answer 43

width distal canine to distal canine heigh central incisor width central incisor

Question 44

how to choose length of anterior teeth?

Answer 44

* High smile line * Previous denture * Measures on mould guides Careful – many cases neck of tooth will be hidden under acrylic so get shorter height of tooth then moulds

Question 45

3 types of cuspal angle

Answer 45

cuspless hybrid teeth (12^o) cusped teeth (13^o)

Question 46

cuspless teeth used for

Answer 46

pts with poor reproducible bite, slide around lot

Question 47

hybrid teeth (12^o)

Answer 47

used for complete, allows some articulation

Question 48

cusped teeth (33^o) used for

Answer 48

too much articulation for complete

Question 49

how to determine posteiror tooth mould

Answer 49

Anterior tooth mould should correspond to posterior on chart

Question 50

how to select shade

Answer 50

* Shade guide * Patient preference * Previous denture * Skin colour * Natural? * Right in notes if you inform them that they have chosen too white one Not B1 – too white, remove before showing

Question 51

how should teeth be arranged

Answer 51

* Personalise the denture * diastema * imbrication etc class 2 div II, proclination etc

Question 52

additional things to consider to personal C/C when deciding tooth shape, position and shade

Answer 52

personalise discuss with pt restorations too make look like no change gingival contour as smooth polished acrylic will reflect light (special instructions)

Question 53

prescription card after occlusal reg

Answer 53

Stage – try in Date – 2 weeks Disinfected Articulate the casts to registration provided Try in of upper and lower teeth – with mould (spaces) Special instructions – spacing between teeth, overlap etc Any adjustments additional to record block (special instructions e.g. restorations, giniva etc)