Prosthodontics Flashcards

1
Q

What are the indications for replacement of missing teeth?

A
to improve masticatory efficiency
to improve speech
preserve or improve oral health by preventing movement of teeth
improve distribution of occlusal loads
space maintenance
restore aesthetics
prepare patient for complete denture
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2
Q

What are the treatment options for replacement of missing teeth?

A
No replacement
bridges (resin retained, conventional)
implant supported prosthesis
removable partial dentures
complete immediate denture
complete dentures
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3
Q

What are the components of a bridge?

A

Bridge - prosthodontic appliance definitively attached to remaining teeth and replaces the missing tooth/teeth

abutment - tooth providing support for bridge

retainer - component cemented on to abutment to provide retention. can be full/ 3quarter covereage crown, post retained, onlay, inlay

pontic - artificial tooth suspended from abutments

connector - component joining pontic to retainer

saddle - area of edentulous ridge

units - pontics + retainers

retention - prevents removal along path of insertion

support - ability to bear occlusal load

resistance - prevents dislodgement in apical or oblique directions

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4
Q

What are the different types of bridge?

A

Fixed - Fixed
fixed - movable

direct - cantilever (one end only)
resin bonded
removable

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5
Q

What are reasons for a bridge failing?

A

loss of retention, mechanical failure, problems with abutments.

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6
Q

What are classifications of edentulous ridges?

A

Kennedy I - bilateral free end saddle
II - unilateral free end saddle
III - unilateral bounded saddle
IV - unilateral bounder saddle which crosses the midline only

classes I-III can have modifications. classify by most posterior saddle only

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7
Q

What are the steps involved in designing partial dentures?

A
Outline saddles
plan support
obtain retention
assess bracing
choose connector
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8
Q

What are the laboratory stages in designing a denture?

A
primary impressions and occlusion -> special trays
(design, survey and tooth preparation)
Master impressions ->tooth trial
(take shade and mould)
try in CoCr frame
Wax try in
delivery
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9
Q

With complete dentures - what is retention and what is it dependent on?

A
resistance of displacement.
dependent on peripheral seal
contact area between denture and tissues
close fit
viscosity and volume of saliva
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10
Q

With complete dentures - what is stability and what is it dependent on?

A

ability of the denture to resist displacing forces during function. supporting tissues and the forces acting on the polished and occlusal surfaaces

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11
Q

What is the neutral zone?

A

where muscular displacing forces are in balanced. the ideal zone for the denture to be placed

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12
Q

List three special impression techniques and when they are used

A

neutral zone impression techniques - when patients have limited natural retention for full lower

flabby ridge technique when patient has compressible ridge on upper anteriors - common when edentulous upper and natural lower

functional impression - tissue conditioner is placed on pt dentures, and they wear their dentures for several days

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13
Q

how do you modify wax rims and record occlusion?

A

trim rim to give correct naso-labial angle
trim anterior to give correct height regarding lip line
trim occlusal plane - parallel to ala-tragus line
mark centre line, canine line and smile line

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14
Q

What denture hygiene advice would you give a patient?

A

remove dentures at night and store in water
clean after every meal with a toothbrush and soap over a full sink
once a week use denture cleaner

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15
Q

What are common denture complaints and what are they caused by?

A

pain - can be roughness, poor OVD, occlusion problems, pathology, RR, exposed foramin

Loose - poor peripheral extension, teeth not in neutral zone, unbalanced articulation, inadequate saliva, poor ridge form, cant adapt

burning mouth - sensitivity to acrylic, candidiasis, xerostomia, psychological conditions

speech - (f and v - incisors palatally placed), (dst - incorrect OJ and OB), (s becomes th - palate too thick), (whistling - palatal vault too high), clicking - OVD or poor retention

cheek biting - teeth not in neutral zone

retching

recurrent # - carelessness, occlusal faults, fatigue, flexing of denture from tori

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16
Q

What is denture stomatitis and how do you manage it?

A

it is a common condition associated with candida albicans infection. Appears as redness under the denture bearing area. increased in incidence if you have f/f, F>M

generally caused by poor denture hygiene and wearing dentures over night. systemic problems can predispose - haematinic deficiencies, diabetes, steroids, drugs, xerostomia, high sugar intake

Manage with good denture hygiene, mechanical and chemical cleaning - can use stearadent. modify aetiological factors.

miconazole gel to fitting surface

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17
Q

When would you provide a copy denture?

A

cant adapt
changing the worn occlusion when fit surface is good
denture has been bleached/discoloured but rest is good
pt wants a spare

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18
Q

When would you provide an over denture?

A

-/F or free end saddles so increase stability and reduce retention
CLP
hypodontia
severe tooth wear

19
Q

What is osseointegration?

A

A direct functional and structural connection between a load carrying titanium implant with the cone with no intervening CT

20
Q

Why is tooth support useful in a partial denture?

A

under load the compressible tissues can move 500um under 4 newtons, whereas teeth move 20um - significantly less compression of the tissues, less movement and increased comfort

21
Q

How would you design a rest seat on a tooth?

A

Rest seat must be able to direct foce down long axis of tooth
basin shaped to allow some rotation
deep enough to allow for metal to not interfere with occlusion - 0.5mm on occlusal surface, 1mm reduction in marginal ridge

22
Q

What features of an RPD give indirect retention?

A

the incisal rests which are 90 degrees to clasp axis

23
Q

what major connector would you use for a lower RPD and why?

A

lingual bar, CoCr.
material offers retention and stability
well tolerated
free of gingival margins

24
Q

17 y/o with congenitally missing 22/23. what options for treatment are there?

A
implants
RPD
bridge (4 units, fixed/fixed)
ortho
combined ortho and restorative
25
Q

What would a dentist check before referral to an implantologist?

A
smoking status
periodontal disease
diabetes
osteoporosis/BP use
blood disorders
26
Q

What does an implantologist check locally for suitability?

A
quality of bone
quantitiy of bone
position of existing teeth
root placement
oral hygeine
27
Q

List Atwoods classification of edentulous ridges

A
I - pre extraction
II - post extraction
III - high and well rounded
IV - knife edge
V - low and well rounded
VI - depressed
28
Q

How would you modify a lower denture for a patient with an unerupted tooth causing problems so that it was stable and comfortable in function

A
soft lining
balanced articulation
polished surface shape and base shape
correct extension onto non-resorbable tissues and retromylohyoid area
correct OVD
29
Q

What is an RPI system and when is it used?

A

it is an occlusal rest, a proximal plate and a gingivally apprioaching I bar clasp
as the denture sinks into saddle, rotation around mesial rest, distal plate and i bar rotate down and mesially, disengage, avoid torquing forces

30
Q

What factors of the denture provide stability?

A

direct and indirect retention, bracing, strong connector, even distribution of rests

31
Q

What problems can occur from increased OVD?

A
clicking when talking
whistling
problems speaking
difficulty eating
pain
32
Q

What problems can occur from decreased OVD

A

poor facial profile
facial discomfort
problems chewing

33
Q

list 3 different ways you can measure the OVD

A

willis gauge
calipers/ ruler to two places which dont move
swallowing

34
Q

how do you test a dentures retention?

A

move cheeks out the way and see how it moves
tip anterior segment forward
pull anterior teeth

35
Q

What is combination syndrome?

A

edentulous maxilla
dentate mand anterior portion
get resorption of the bone - hypertrophic and atrophic changes. ends up with flabby fibrous tissue deposited max ant

36
Q

What are the management options for a knife edge ridge?

A

check for sore points on ridge by pressing
cut relief in impression and take mucostatic impression there (light body PVS)
soft lining on knife edge

surgery to smooth

37
Q

What are the benefits of a shortened dental arch?

A
good occlusal stability
good functionality
aesthetic
cost efficient
easier to maintain
38
Q

what are contraindications for SDA?

A

remaining teeth arent in favourable occlusion
TMJ
significant malocclusion
restorations required in the 20 teeth to be used

39
Q

What are the choices for a lower major connection and when are they used?

A

lingual bar: 8mm of space (3mm FGM, 4mm bar, 1mm from sulcus). need good OH and perio support

lingual plate: if no space for bar. may cause perio problems

Dental bar: less used

40
Q

what is indirect retention?

A

resistance to vertical displacement by counteracting the axis of rotation provided by direct retention

41
Q

What is the difference between a soft lining on a denture and a tissue conditioner?

A

a soft lining is used in tissue health as a reline or shock absorber. a tissue conditioner is used in poor tissue health - candida or ulcers to aid healing and dissipate forces - short term option

42
Q

What features of complete dentures do you check at try in?

A

extension, retention, stability, aesthetics, OVD, occlusion, teeth position, patient thoughts

43
Q

What are the extensions for upper and lower dentures?

A

upper: hamular notch to hamular notch, along vibrating line

lower - 2/3 up retromolar pad

44
Q

What aspects make up the shade of a tooth?

A

hue, chroma, value, translucency