prosthodontics Flashcards
effects of edentulism - 4
loss of masticatory function
self esteem
poorer quality of life
speech
cawood and Howell ridge resorption classifications
1 = before extraction
2 = immediately after extraction
3 = high well rounded ridge
4 = knife edge ridge
5 = low well rounded ridge
6 = depressed ridge
why is a parkinsons pt not suitable for dentures
dentures require good neuromuscular control
what compromises stability of lower denture
tongue movements
reasons to render a pt edentulous - 5
advanced perio/ hopeless teeth
rampant caries
severe and debilitating tooth wear
pre surgery - infection risk
pre chemotherapy - infection risk
4 reasons older people get caries
xerostomia
sjogrens syndrome
dementia
radiation caries
3 methods of complete denture construction
conventional
digital
replica
when would you make a conventional denture
no previous denture or previous denture unsuccessful
how would you modify a stock tray
green stick wax
soft red wax
putty
reduce with acrylic bur on straight hand piece
good impression material to use for retching pt
red composition
3 things to assess edentulous impression for
are all edentulous areas included
are sulcus areas included in denture recorded fully
are there any deficiencies - air blows
spacing for special tray when impression will be taken with alginate/heavy bodied elastomers
3mm
spacing for special tray when impression will be taken with light bodied elastomers
no spacing
advantages of taking a master impression - 3
accurate peripheral extension
records denture bearing area accurately
reduced material - more comfortable
aims when taking master impression - 3
all relevant areas recorded
no air blows
well rounded borders
information to gather when taking denture history - 3
age of denture
how many sets
success?
dental history for complete denture questions - 3
why teeth loss
when teeth lose
any retained roots, pain or swelling
what medical problems influence patient suitability for denture
neuromuscular problems
parkinsons
stroke
dementia
dry mouth
sjogrens
define support of a denture
resistance of vertical movement of a denture towards ridge
primary and secondary support area of upper compete
primary - hard palate
secondary -ridge crest
primary and secondary support areas of lower complete denture
primary - buccal shelf and retromolar pad
secondary - ridge crest
what is ICP
complete intercuspation of opposing teeth independent of condylar position
what is RCP
guided occlusal relationship occurring at most retruded position of condyles in joint cavity - most reproducible
define stability of denture
ability of denture to resist displacement by functional stresses in a horizontal direction
define retention of denture
the resistance to vertical displacement of denture away from tissues
define adaptation of denture
degree of fit between a prosthesis and supporting structures
clinical and lab stages of replica denture - 8
replica mould of old denture
lab makes replica block
master impression and bite registration
cast impressions and mount casts and set up
try in
process and finish dentures
delivery/insertion
review
denture try in checks
Lip support
appearance
even contact in RCP
speech
retention and stability
base extensions
lower teeth over ridge
denture insertion checks
appearance
even contact in RCP
speech
retention and stability
base extensions
comfort
denture review checks
pain redness ulcers
function
aesthetics
speech
OVD
mucocompressive impression meaning
pressure is applied and shape of tissue under load is recorded
mucostasis impression meaning
minimum pressure applied and tissue shape at rest is recorded
how could you alter impression technique for flabby ridge
use perforated tray over ridge
alginate in non-flabby area - mucocompressive
light bodied silicone on flabby area - mucostatic
conventional clinical and lab stages - 10
primary impressions
primary casts and special trays
master impression
master casts and record blocks
jaw registration
mount casts and set up teeth
try in
process and finish
insertion
review
when would you chose a close fitting tray oner 3mm spaced tray
resorbed ridges
steps of jaw reg - 7
adjust upper for retention
adjust upper for tooth position
adjust upper for occlusal plane
lower tooth position and horizontal jaw relationship
OVD
record registration
shade mould and setting
what does LIMBO stand for and when do you use this
Lip support
Incisal Level
Midline and canine lines
Buccal corridor
Occlusal plane
use when adjusting record block for complete conventional denture
recommended nasiolabial angle and edentulous nasiolabial angle
90
96 in edentulous
what reference do you use to check anterior occlusal plane
interpupillary line
reference for posterior occlusal plane
ala tragus line
what is the neutral zone
space between the lips and cheeks one one side and the tongue on the other - area where forces between tongue and cheeks/lips are equal
OVD definition
distance between set point on maxilla and set point on mandible when teeth/denture are in maximal intercuspation
RVD definition
when mandible is at rest, distance between point on mandible and point on maxilla
what can affect RVD measurement
stress
pain
anxiety
tense up facial muscles
what are the effects of excessive freeway space - 3
reduced masticatory efficiency
overclosed appearance
TMJ pain
effects of reduced FWS - 3
excessive load on denture bearing area
continuous muscle activity - pain
noisy dentures
normal FWS
2-4mm
what articulator requires face bow
semi adjustable
materials used for artificial teeth - 3
porcelain
composite resin
acrylic
what do the numbers mean on mould guide top to Botton
mould
width of 6 ant teeth flat
width of L central
height of L central
factors influencing shade and shape selection
pt opinion
photographs
old dentures
existing teeth or partials
what factors influence posterior teeth choice - 2
ridge width
neuromuscular control
when would you consider cusp less teeth
when it is difficult to get reproducible jaw relationship
before the patient arrives for a try in, what do you check the lab work for
correct patient
correct prescription
correct mould and shade
special instructions adhered to
damage?
complete denture try in check list
retention and stability
base extensions
LIMBO
position of teeth
FWS
even contact in RCP
speech
aesthetics
how would you test pt speech with denture
fricatives
count 60-70
days of week
s sound when testing speech
too much FWS or too class 2 as too much air escaping
correct by adjusting ant tooth position or increasing OVD
teeth contact during speech
reduce OVD and insufficient FWS
what can you use to aid detection of areas causing discomfort from new denture
pressure indicating paste
denture hygiene advice - 5
brush dentures daily - non abrasive
rinse after meal
soak dentures daily - 20 mins with alkaline peroxide or hypochlorite - 10 mins if metal - rinse then soak over night in cold water
leave dentures out at night
visit dentist regularly
reasons poor denture hygiene - 4
poor manual dexterity
xerostomia
wearing dentures full time
lack of knowledge
what forms the pellicle layer
salivary proteins and bacterial. products
fusobacteria produces sulphur products, what is the effect of this on oral cavity
halitosis
why do fungal spices adhere to dentures
candida has affinity for PMMA
acidic environment under denture favours candida activity
why does debris accumulate on denture
denture surface not smooth
decreased salivary flow in elderly
fit surface nor exposed to cleaning effects of saliva
what are the effects of poor denture hygiene - 4
caries
halitosis
denture stomatitis
periodontal disease
most common mechanism for pneumonia in elderly
respiration of food, reflux and oral bacteria into lower respiratory tract
how do dentures impact aspiration pneumonia
dentures act as reservoir for potential respiratory pathogens thus increasing risk of aspiration pneumonia
3 ways to mechanically clean denture
soap and soft brush - toothpaste and not soft will scratch acrylic
microwave for 20 secs
ultrasonics
chemical denture cleaners - 2
alkaline peroxide
alkaline hypochlorite - not for soft lining
acids - not for metal or soft linings
what health benefits are there of removing dentures and soaking them over night
prevents stomatitis and aspiration pneumonia
advantages of immediate denture -4
self esteem
function
post extraction healing
avoid drifting of teeth
disadvantages of immediate denture
poor fit stock tray
contraindications of immediate denture
MRONJ
dementia
pre chemo / pre radio
when is rate of resorption most rapid
first 6 months
steps of immediate denture to replace one or two anterior teeth that have been affected by trauma or tooth fracture
impressions U and L
intra occlusal record
choose shade
prescription to library with design and teeth gonna be extracted
extraction and insertion same day
4 displacing forces that affect denture
gravity
muscle activity
function
sticky foods
define adhesion - give 2 examples
physical attraction of unlike molecules for each other
saliva and mucous membrane
saliva and denture base
define cohesion
physical attraction between like molecules
e.g. saliva film
what is atmospheric pressure important for in dentures
border seal
3 necessary aspects of denture fitting surface
full coverage of denture bearing area
good adaptation to mucosa
adequate post dam seal maxilla
adequate extension into lingual pouch
another name for retromylohyoid fossa
lingual pouch
5 factors that make retention and stability difficult
atrophic ridges
congenital cleft
fibrous ridge
gagging - can’t tolerate base extension
CoCr adapts less well than acrylic
aids to denture adhesion and stability - 2
denture adhesives
linings
implants
what directly impacts adaptation of denture
good impression
why is it important to relieve the incisive papilla
compression of nasopalatine nerve and vessels by denture
leads to necrosis of areas supplied and paraesthesia of anterior palate
what is a relief area
denture should be designed so masticatory load is relieved from these areas as these areas can be easily traumatised e.g. thin mucosa or fragile underlying structures or resorption under constant load
what is the lingual frenum
fibrous band covered in mucosa
important not to be covered by denture as will cause pain and instability
denture must extend adequately around though without encroaching to ensure peripheral seal
relief areas for upper denture
incisive papilla
3 limiting structures for upper denture
buccal sulcus
labial sulcus
lingual and buccal frenum
relief areas of lower denture - 2
mylohyoid ridge
support areas of lower denture
primary - buccal shelf and retromolar pad
secondary - residual alveolar ridge
3 limiting structures of lower denture
retromolar pads
buccal and labial and lingual frenum
buccal and labial sulcus
4 objectives of complete dentures
adequate masticatory function
restore natural appearance
restore normal speech
comfort and preservation of supporting structure
4 objectives of complete dentures
adequate masticatory function
restore natural appearance
restore normal speech
comfort and preservation of supporting structure
4 factors affecting retention of complete dentures and give examples of each
physical - adhesion, cohesion, atmospheric pressure, gravity
anatomical - shape of edentulous area, undercuts
physiological - neuromuscular control, saliva viscosity and volume
mechanical - balanced occlusion, position of teeth to ridge and occlusal plane
what is atmospheric pressure
hydrostatic pressure due to weight of atmosphere on earths surface
where should teeth be positioned in respect to lower ridge - 2
directly above lower residual alveolar ridge
within neutral zone
what should the horizontal distance be between the probe on the incisive papilla and and the probe against the incisor edge of the incisor edge of maxillary central incisors be?
1cm
height and width of lower record block
18mm height
10mm width
2/3 of retromolar pad height
height and width of upper record block
H ant. 22mm
H post. 18mm
W ant 5-7mm
w Post. 10mm
anatomical landmark to use to mark centre line
distal of incisive papilla - 10mm to labial surface of incisor
alma gauge use
determines the vertical and horizontal position of anterior teeth relative to a point on the denture base (e.g. incisive papilla).
types of indirect restorations
veneers
inlays/onlays
crowns
post and core
bridge
why place a veneer - 4
improve aesthetics
change tooth shape/colour
correct peg shape laterals
reduce/close diastema
4 contraindications to venners
poor OH
high caries
gingival recession
heavy occlusal contacts
onlay/inlay indications - 3
tooth wear
fractured cusps
restoration of RCT
when to use crowns - 3
to protect weak tooth
improve aesthetics
retainer for bridgework
contraindications to crown - 3
more conservative option availible
active caries/periodontal disease
lack of tooth tissue for prep
what are the 6 principles of crown prep
preservation of tooth structure
retention and resistance
structural disability
marginal integrity
preservation of periodontist
aesthetic considerations
why preserve tooth structure - 2
prevent unnecessary weakening of tooth
protect pulp
result of over prep for crown
pulp and tooth strength compromised
underprop of crown result
poor aesthetics
overbuild crown
insufficient thickness of crown
meaning of retention of crown
prevents displacement of crown along long axis of tooth prep
meaning of resistance of crown
prevents dislodgement of crown by forces on crown including occlusal
ideal taper of walls of crown
6-10
what property does limiting the number of paths of insertion of a crown improve
retention
how do you give structural durability to a crown
functional cusp bevel
occlusal reduction
axial reduction
how do you ensure periodontist is preserved when placing a crown - 3
margins smooth and fully exposed to cleaning
placed where dentist can finish them and patient can clean them
placed supra gingival or at gingival margin if possible
what is an indirect restoration
restoration fabricated outside mouth by technician in lab
what is an inlay
intracoronal restoration made in lab
3 materials used for inlay and onlay
composite
gold
porcelain
indications for an inlay - 2
premolar or molar
occlusal restoration
what advantages do inlays have over direct restorations
superior materials and margin
won’t deteriorate over time
ceramic inlay prep - isthmus and margin
1.5-2mm isthmus
shoulder or chamfer 1mm
gold inlay prep
1mm isthmus
0.5 chamfer margin
what is an onlay
extra coronal restoration made in lab - like inlays but with cusp coverage - require cuspel reduction
indications for onlay
sufficient occlusal tooth substance loss
remaining tooth surface weak - caries
what margin design is used for onlay or inlay
porcelain 1mm shoulder or chamfer
gold 0.5mm chamfer
alternative to inlay/onlay - 2
large direct restoration
crown
extraction
materials for veneer
ceramic
composite
gold
4 intrinsic causes of enamel discolouration
tetracycline
fluorosis
ageing
non vital teeth
labial reduction and incisor reduction for veneer
0.3 cervical - 0.5 labial mid
1-1.5 incisal
alternative option for temporary veneer
spot bonded composite - no etch, use bond only and apply composite
alternatives for veneer restoration
no treatment
microabrasion
ICON - penetrative resin restorations
crowns
material for provisional restoration
chemically cured bis acrylic composite
pro temp
materials for preformed provisional crown
polycarbonate
clear plastic
metal - SS
problems with preformed crown
unlikely to fit accurately
large bank of crowns are needed - costly
when are preformed crowns useful
when no impression is taken prior to tooth prep or damage
what do you use to cement temporary crown
temporary luting cement e.g. temp bond
advantages of indirect provisional restorations
accurate
low shrinkage
high strength
indirect provisional restorations material - 3
composite
acrylic - common
meta
