complete dentures Flashcards
anatomical effects of edentulism
bone resorption - max rate first 3m
profile changes
loss of muscular support
reduction in face height
physiological effects of edentulism
reduced incising efficiency reduced masticatory efficiency loss of proprioception reduced swallowing efficiency reduced speech quality
average bone loss - incisors
6.5mm
average bone loss - canines
8.5mm
average bone loss - premolars
10.5mm
average bone loss - molars
12.5mm
design principles
retention extension support stability aesthetics occlusion
how many classes in Cawood and Howell ridge classification?
6
Cawood and Howell ridge classification - 1
dentate (pre-ext)
Cawood and Howell ridge classification - 2
immediate post-ext
Cawood and Howell ridge classification - 3
high well-rounded broad alveolar process
Cawood and Howell ridge classification - 4
knife edge ridge (painful loading)
Cawood and Howell ridge classification - 5
flat ridge (no alveolar process) low well rounded
Cawood and Howell ridge classification - 6
submerged ridge (loss of basal bone) depressed
U denture extension
sulcus depth all way round avoid frenal attachments extend to vibrating line - jct HP/SP - 1-2mm anterior to palatine fovea
L denture extension
sulcus depth all way round
avoid frenal attachments
2/3 onto RM pad
retention
resistance to vertical displacement of the denture away from the edentulous ridge
what is retention provided by?
accurate fit
border seal
retromylohyoid area (L)
support
resistance to vertical displacement of the denture towards the denture bearing tissues
U support areas
residual ridge
HP
L support areas
residual ridge
buccal shelf
anterior 2/3 RM pad
stability
resistance to horizontal displacement of denture
L often significantly worse
achieving stability
adequate extension using retromylohyoid area balanced occlusion utilising muscular forces in neutral zone - lips and cheeks from outside - tongue from inside
aesthetics - tooth shade
translucency
value
hue
chroma
aesthetics - profile
lip support
creating a normal lat view of the pt
Balanced occlusion: Hanau’s Quint
Compensating Curve Orientation of the occlusal plane Cuspal angle 0-30 degrees Condylar guidance angle 30 degrees Incisal guidance angle 15 degrees
OVD definition
height of the face from the lower border of the nose to immediately underneath the chin when the teeth are together
overly increased OVD
TMD
poor masticatory efficiency
speech problems
facial pain over masseter
inadequate OVD
angular cheilitis
occlusal trauma
clicking teeth
RVD
the height of the face from the lower border of the nose to immediately underneath the chin when the teeth are apart at rest
FWS
difference between OVD and RVD
should be 2-4mm
EO exam
face shape profile changes smile line nasolabial angle
IO exam
ridge shape (attwood and howell) undercuts - spicules/irregularities consistency - firm, friable (flabby), jagged (knife edge) tissue health saliva flow and quality sulcus depth muscle relationships skeletal relationships AP
primary impressions - what determines the material?
assess if undercuts
- UCs - alginate (irreversible hydrocolloid)
- no UCs - impression compound (non-elastic)
silicone putty (£)
usually use same material for U and L
primary impressions - lab prescription
please pour up impressions in 50/50 stone and plaster
construct special trays in light cure PMMA (no perforations)
- U: EO handle
- L: EO (IO handles with stub handles over premolars)
spacer - for the material you will use for master
- alginate 3mm
- silicone/compound/polyether: U 2mm, L 1mm
master impressions
check extension and trim special tray
modify with greenstick
use PVS (extrude) - medium body
- hydrophobic so will create blebs - dry mucosa
Polyether (impregum) is an alternative, has one viscosity but is hydrophillic
or alginate
master impressions - modifying with greenstick
U: canine stops, post-dam extension, full posterior border of tray
L: canine stops, RM pad
both: add material to fill functional sulcus and border mould
master impressions - lab prescription
please pour up master impressions in 100% dental stone
construct U and L wax occlusal rims on light cured bases
please do to post dam as marked
jaw registration first stage
adjust upper record block to maximise retention
- trim any overextensions otherwise will drop
- lip support
- adjust rim vertically until roughly happy - don’t adjust too much so you have room for occlusal plane determination
jaw registration second stage
adjust upper record block for tooth position
LIMBO
lip support (90-110 degrees)
incisal level (0.5-1.5mm show), high smile line
midline, canine
buccal corridor
occlusal plane - ala tragus, interpupillary (don’t alter incisors - you have already done that)
- use prev dentures if available
jaw registration 4th stage
vertical dimension and establish face height
- RVD and OVD
- to get OVD try and replicate their RCP as this is what you’ll use later - lick lips and look out window absentmindedly. check heels aren’t in contact - cut where L7s would be
- measure RVD
- 2-4mm FWS - adjust lower block if want to change
jaw registration 3rd stage
lower tooth position
- set L teeth on ridge
neutral zone
lower polished surfaces - aim to direct forces of tongue in favour of denture stability - triangular - base wider than top - tongue will help push it down
jaw registration 5th stage
registration
make 2 location notches in the premolar region to allow them to be accurately articulated
Jetbite
jaw reg 6th stage
selection of teeth
shade - translucency, hue, value and chroma - shade guide, pt preference, prev denture, skin colour
*not B1 - far too white for most denture pts
cusped, cuspless or hybrid
shape - mould, prev dentures, photos (careful)
jaw reg lab prescription
please mount casts to the registration recorded on an average value articulator
set U teeth to the record block
set L teeth to the U teeth
see shade and mould overleaf
things to check in tooth trial
check on model first assess each denture independently and then together retention extension support stability aesthetics occlusion and occ planes OVD, RVD, FWS speech pt view post dam
tooth trial - retention
pull sharply down on anteriors
get pt to raise tongue for L
tooth trial - extension
check fct sulcus filled
postdam included
no uncomfortable overextensions/loose underextensions
tooth trial - support
push down on occlusal surfaces of teeth
should displace slightly but not overly so
look for bony spicules and relieve
tooth trial - stability
grab molars and move side to side
use retromylohyoid area to maximise this
neutral zone respected?
tooth trial - aesthetics
pt happy? profile midlines smile line buccal corridors
tooth trial - occlusion
mandibular occlusal plane at level of RMP
practice in retruded arc of closure
even contacts
tooth trial lab prescription
please wax up for finish and process in heat cured PMMA
also mark post-dam - please prep post dam to…
IF retrial
- remount casts and make specified changes for second trial
delivery
do same checks as tooth trial
any trimming
give denture advice sheet
review in 2wks
looseness - adjusting the fitting surface
rebase
reline
- hard: chairside or lab
- soft: tissue conditioner or soft
hard reline
chairside - butylmethacrylate (non-irritant)
lab - PMMA
tissue conditioner
infected tissue helps healing can do fct impression by keeping it in for 24hrs short term 2-4 weeks
soft reline
long term pain - from bony prominences, residual monomer, RR or pathology atrophic ridge superficial mental nerve bony prominences omfs xerostomia
looseness - occlusal surface
premature contact - grind down
incorrect occlusal plane - remake
locked or wedged occlusion - use cuspless teeth
looseness - polished surface
rare but may be from tongue rubbing/cheek biting - relieve
general poor retention
reline rebase implant retained precision attachment add post dam
rebase
entire fitting surface altered with hard acrylic
replica denture procedure
apply fix to fitting surface of one tray and the outside of another tray (bottom)
lab putty, 5 scoops to one width of activator
set denture into tray as you normally would and adapt putty
3 locating notches into putty
Vaseline on set lab putty
put new ball of putty onto the fitting surface of denture already in imp and push hard
push second tray hard (upside down) onto it (fixed on back side)
match location notches
lever denture out from heel to minimise fracture risk
wash denture, return to pt
put imps back together
you will be given a shellac base and record block for jaw reg next visit
restoration of FWS
occlusal pivots
restore occlusal surface with autopolymerising resin
what is a knife edge ridge?
rapid resorption of lingual and buccal bone resulting in a narrow ridge
reasons for a knife edge ridge
immediate dentures
severe PDD before XLA
traumatic surgery before XLA
management of a knife edge ridge
surgical removal of bony spicules
soft liner on denture
flabby ridge process
combination syndrome
cause of combination syndrome
forces directed at upper anterior ridge covered by a denture occluding with dentate lower causes rapid resorption of maxillary ridge
the overlying tissue becomes v fibrous and flabby
management of combination syndrome flabby ridge
mucostatic impression material
window technique - 2 stage impression with wash - cut out square in the tray and inject light body
relief holes precut before you take impression
advantages of immediate denture
maintain ST haemorrhage control reduce risk of dry socket psychological benefit aesthetics prevent ST collapse maintain muscle tone
disadvantages of immediate denture
knife edge ridge poor fit with resorption no trial stage so can't refine difficult with surgical XLA as bone removal requires reline/rebase
alkaline hypochlorites
e.g. dentural, milton don't leave CoCr for >10mins - can corrode superior cleaning properties effective dissolution of plaque stain removal properties bacterial and fungicidal properties possible bleaching of acrylic resin residual taste after use
effervescent peroxides
steradent
powder/tablets
rapid action, easy to use
problems can arise if hot water used with denture, can cause bleaching
additional mechanical cleansing action
bubbles created by the release of O2 which may dislodge debris
basic denture hygiene advice
brush and soak every day
what should you do before soaking dentures?
use a soft brush and non-abrasive cleaner (not toothpaste)
denture stomatitis - organism
c albicans
denture stomatitis - aetiology
wearing at night poor OH diabetes immunocompromised xerostomia
initial denture stomatitis tx - local measures
brush palate daily
clean dentures thoroughly by soaking in CHX MW or NaOCl for 15mins x2 daily (only use NaOCl for acrylic)
leave dentures out as often as possible during tx period
if dentures are identified as contributing to the problem - adjust/remake to avoid recurrence
what can you use for denture stomatitis if you are making a new denture?
tissue conditioner to temp reline current one
CHX MW for denture stomatitis
effective against fungal infections
denture stomatitis - what can antifungal agents be used for?
adjunct
esp to reduce palatal inflammation before taking imps for new dentures
first line antifungals for denture stomatitis
fluconazole capsules 50mg
miconazole oromucosal gel 20mg/g
fluconazole capsules dose
50mg
7 capsules x1 daily
max 14 days for tx of this
contraindications to fluconazole
on warfarin/statins
miconazole oromucosal gel dose
20mg/g
80g tube
apply pea-sized amount to fitting surface of U denture after food x4 daily, then reinsert
continue to use for 7days after lesions have healed
contraindications to miconazole oromucosal gel
warfarin/statins
denture stomatitis - if fluconazole/miconazole contraindicated
nystatin oral suspension 100 000units/ml
nystatin oral suspension dose
100 000units/ml
30ml
1ml after food x4 daily for 7 days
remove dentures, rinse suspension around mouth then retain suspension near lesion for 5mins before swallowing
continue use for 48hrs after lesions have healed
maxilla - limiting structures
labial frenum labial sulcus buccal frenum buccal sulcus hamular notch vibrating line
maxilla - relief areas
incisive papilla
palatine raphe
crest of alveolar ridge
palatine fovea
maxilla - supporting structures
rugae
posterior palate
tuberosity
limiting structures
guide optimum extension - engage max SA without enroaching upon muscle actions
symptoms of overextension
dislodgement of denture
soreness
symptoms of underextension
reduced retention, stability, support
relief areas
areas where resorption under constant load, fragile structures or covered by thin easily traumatised mucosa
masticatory load shouldn’t conc on these areas
supporting structures (stress-bearing areas)
most of load should be concentrated on these areas
labial frenum
fibrous band covered by mucous membrane
labial aspect of residual ridge - lip
passive - no muscle fibres
V labial notch on denture - narrow but deep enough to avoid interference, seat around frenum - peripheral seal
labial sulcus boundaries
teeth, gingiva and residual alveolar ridge
lips
runs between buccal frenums
buccal frenum
fibrous band covered by MM
need greater clearance (shallower and wider) than labial frenum
buccal frenum attachments
levator anguli oris
orbicularis oris
buccinator
buccal sulcus location
buccal frenum to hamular notch
size of buccal sulcus vestibule depends on:
contraction of buccinator
position of mandible
amount of bone loss in maxilla
hamular notch
depression between distal of tuberosity and hamular process of MP plate
soft area of loose CT
where should the distal border of the U denture extend and why?
hamular notch
helps with posterior palatal seal
vibrating line
junction between hard and soft alate - division between moveable and immovable tissue of soft palate
on posterior part of palate, between hamular notches
identifying the vibrating line
ask pt to say ahhh
mark with pressure indicating paste
vibrating line and palatine fovea
vibrating line usually 2mm in front of palatine fovea
importance of vibrating line
denture needs to extend here to get seal
incisive papilla
midline, behind central incisors
exit point of nasopalatine nerves and vessels
relieve - if not nerve/vessels compressed - necrosis of distributing areas and paraesthesia of anterior palate
palatine fovea
2 depressions approx 2mm behind vibrating line
palatine raphe
incisive papilla to distal end of hard palate
median suture area covered by thin submucosa
relieve - most sensitive part of palate to pressure
maxilla primary supporting area
posterior palate
maxilla secondary supporting areas
rugae
tuberosity
lower labial frenum
fibrous band with CT
labial of residual ridge to lip
helps in attachment of orbicularis oris
sensitive - labial notch
mandible - limiting structures
lingual frenum labial frenum labial sulcus buccal frenum buccal sulcus alveololingual sulcus retromolar pad
mandible - supporting areas
buccal shelf
residual alveolar ridge
mandible - relief areas
genial tubercle
mylohyoid ridge
torus mandibularis
which muscle is active in the lower labial sulcus region?
mentalis
lower buccal frenum
attaches fibres of buccinator
relieve - prevent denture displacement
lower buccal sulcus
buccal frenum to outside back corner of retromolar region
why can the lower buccal sulcus be safely area maximised?
fibres of buccinator run parallel to border so displacement due to buccinator is slight
imp at widest here
lingual frenum
attaches tongue to alv process
relief
retromolar pad
pear shaped soft pad of tissue at posterior end of ridge
forms posterior seal and support
denture should extend up to anterior 2/3
alveololingual sulcus
lingual frenum to retromylohyoid curtain
overextension - soreness and instability - assess extension by moving tongue R and L
divide into 3:
1 - anterior part: lingual frenum to mylohyoid ridge
- shallowest (least height part) of the lingual flange
2 - middle region: premylohyoid fossa to distal end of mylohyoid region
3 - posterior portion: mylohyoid ridge end to retromylohyoid curtain
- undercut area - retention
genial tubercle
muscle attachment - genioglossus and geniohyoid
lies away from crest of ridge
prominent in resorbed ridges - relief needed
torus mandibularis
abnormally bony prominence
bilaterally on lingual side near premolar area
thin mucosa - relieve
mylohyoid ridge
mylohyoid attachment
along lingual surface of mandible
anteriorly close to inferior border of mandible
posteriorly close to residual ridge
thin mucosa - relieve
extension of lingual flange beyond the palpable position of the mylohyoid ridge, but not in the undercut
buccal shelf
primary stress bearing/supporting area
buccal frenum to RM pad
between EOR and crest of alveolar ridge
width increased as alveolar resorption continues
residual alveolar ridge mandible
secondary supporting area
buccal and lingual slopes are secondary areas
retromylohyoid space
distal end of lingual sulcus posterior to mylohyoid muscle
aids retention and stability
- can’t get sideways movement
- often a small UC
where is the loss of bone more significant?
in the mandible
maxilla alveolar ridge resorption
anteriorly - resorbs palatal direction
posteriorly - narrows palate
mandible alveolar ridge resorption
anteriorly - more vertical
posteriorly - down and out, widens mandible
- often make dentures with a CB
EO changes
changes in upper lip (lack of support)
changes in lower lip
change in lower face height
change in profile - appear class 3 due to rotation as close
nasolabial angle increases
bone resorption reduces support for muscles/ST
psychological factors of edentulism
relief of no more teeth lost limb syndrome embarassment denial (partner doesn't know) depression
definition
a removable dental prosthesis that replaces the entire dentition and associated structures of the maxilla or mandible and can be replaced by the pts own free will
objectives
provide adequate masticatory fct
restore natural appearance
restore normal speech
comfort and preservation of supporting structures
parts
base
flange
border
teeth
surfaces
fitting
polished
occlusal
factors affecting success
retention
stability
support
physiologic comfort
psychological comfort
longevity
testing retention
pull vertically on anterior teeth away from tissues
care not to tip by uneven forces
aspects which lead to good retention
fit - no space between
border seal - flanges, postdam
no interference with muscle/frenal attachments
factors affecting retention
physical
anatomical
physiological
mechanical
physical factors affecting retention
adhesion
cohesion
atmospheric pressure
gravity
adhesion
the forces of attraction existing between dissimilar bodies in close contact (between saliva and denture base)
cohesion
forces of attraction existing between similar bodies in close contact (surface tension of saliva)
atmospheric pressure
the physical factor of hydrostatic pressure due to the weight of the atmosphere on the earth’s surface
gravity
works against Cu, and for Cl
anatomical factors affecting retention
shape of the edentulous area
undercuts
anatomy of the border tissues
anatomy of maxilla class 1
square
anatomy of maxilla class 2
V
anatomy of maxilla class 3
flat
physiological factors affecting retention
NM control
viscosity and volume of saliva
mechanical factors affecting retention
balanced occlusion - bilateral simultaneous, anterior and posterior occlusal contact in centric and eccentric position
contour of polished surface - teeth and polished surface should be contoured and harmonious with oral structure
position of occ plane - occ plane of L must be in correct level ie corner of mouth provides anterior landmark
position of teeth in respect to ridge - L posterior teeth are positioned directly above the lower residual ridge, and within the neutral zone
testing stability
place fingers on occ surface and try to rock the denture side to side
tx options
Cu and Cl Cu or Cl - most common Cu and lower teeth nothing implant supported removable prosthesis implant supported fixed prosthesis
stages in conventional dentures
assessment of pt and dentures, primary imps master imps jaw reg tooth trial delivery review
stages in replica dentures
assessment of pt and dentures, replica imps master imps and occlusion (same visit) try in delivery review
pt assessment of dentures
age of dentures denture hygiene appearance movement comfort speech chewing biting satisfactory/unsatisfactory
denture assessment
current denture design base extension in all areas tissue adaptation retention and stability - position of teeth, occ plane relationship of dentures appearance other factors diagnosis/problem list
tissue adaptation
shouldn’t see spaces between mucosa and fitting surface of denture
where should U teeth be set?
slightly buccal and labial to the ridge
tongue space and prevent stress and fracture of base
where should L teeth be set?
over ridge as ridge resorbs straight down
too much FWS
overclosure, more prone to angular cheilitis
too little freeway space
speech, TMJ, pain over denture-bearing area
ideal articulation
group fct - contact and balance both sides
neutral zone
musculature either side is equal
materials for primary imp
alginate
(impression compound)
silicone
alginate pros and cons
cheap, easy to use, elastic, quite accurate
can be messy, poorish dimensional stability - need to pour quickly
impression compound - what should it not be used for?
dentate pts - except e.g. for a FES
because non-elastic
imp compound pros and cons
poor surface detail - only for primary imps
not cheap anymore
can be messy
silicones
dimensionally stable hydrophobic consistencies - light, med, putty can be messy to use v accurate
polyether (impregum)
dimensionally stable
hydrophillic - tend to get less saliva bubbles
no variety of consistencies (med body)
can be messy to use
v accurate
v solid - so in stone single teeth may come off in cast
need vaseline on lips
ZOE
mainly historic
thick
not elastic
mucocompressive - good for posterior flabby ridge
reversible hydrocolloid (agar)
mostly historic
lab for duplicating casts
impression definition
a reverse/negative form of the tissues which is converted into a positive model/cast using plaster or stone
correct sized primary tray
fully engages over alveolar ridge and depth of tray comes fully into sulcus
adhesive
2-3mm beyond edge of tray on the external surface
inspection of primary impression
covered denture bearing area?
achieved a good peripheral seal? - hard to remove and sucking sound
recorded adequate surface detail?
suitable to produce a satisfactory primary cast?
trying in the U special tray - what to do if it is under/over extended
over - reduce extension
under - correct during border moulding
border moulding
addition of material to the outside of the periphery of the trays to fill the functional sulcus
greenstick or silicone
don’t bring onto fitting surface
not always needed for alginate but usually need for silicone/polyether
- they don’t hold shape as well so don’t hold sulcus depth well
once the material is still soft and you place in mouth you manipulate the tissues - gives width of sulcus
occlusal stops - creating space in the upper tray
function is to make sure we have the correct thickness of imp material
can use GS/silicone putty
‘stops’ to the space prescribed in the canine (palatal) and post-dam regions
allow accurate correction of the posterior borders of the tray and will pre-form space for the imp material
- make tray more stable
- stop you pushing tray in too far (tissue compression)
stops should involve the whole of the posterior border of the tray
light body silicone - 1mm thick
alginate - 3mm thick
creating space in the lower tray
‘stops’ to the space prescribed on the RM pad and on the ridge in the canine areas
allows space for the imp material
assessing your master imp
same as primary
good functional sulcus?
good surface detail?
modifying a denture with the replica technique
temp modify the old dentures with GS
prescription for replica dentures impressions
replica blocks in wax/shellac
- shellac base, wax polished and tooth surfaces
slightly flabby/fibrous ridge
ask for extra spacing on tray
ask for perforations in area of ridge - so material can flow down and not displace ridge
runny alginate
mucostatic window technique for flabby ridge - how to ensure lid doesn’t apply pressure
lid peripheries will overlap special tray bordering the flabby tissue to prevent compression (2mm)
lid has own handle to support it - ensures no pressure applied to flabby tissue
what material is used for the spacer?
wax
how to aid creating a posterior palatal seal with impressions
ask pt to blow through their nose while their nostrils are pinched closed
- increases intranasal pressure to allow soft palate to mould the GS
disadvantage of silicone putty compared to GS for border moulding
silicone can’t be refined
gagging tips
open mouth wide
breathe through nose
wiggle toes
how should you place material in tray to prevent any air getting in and causing blows?
keep tray close to material dispenser
boxing in
addition of ribbon wax - preserve width and depth of sulcus when it comes to casting master imp
at least 4-5mm from the deepest vestibular sulcus depth
‘land area’
advantages of impregum over silicone
fixotropic - runs when border moulding but holds shape when not
hydrophillic
slightly thicker
what should the horizontal distance between the index finger on the incisive papilla and the probe against incisal edge of labial surface of maxillary incisors be?
1cm
what should you do on the primary imp if you think it is overextended?
draw where you would like the special tray border to finish
registration stage objectives
define the shape of the maxillary rim determine occlusal plane define position of lower teeth determine jaw relationship select shade and mould
how to mark canine line
use floss down from canthus of eye, ala of nose and down
arch and buccal corridor
broad arch = small buccal corridor
narrow arch = broad buccal corridor
how much tooth gets seen
overbite
want shallow
if too deep, when protrude dentures will rock against each other - displaced
posterior teeth occlusion
normal occlusion - bone resorption - can get normal occlusion if you push U teeth outwards beyond the ridge (would affect buccal corridor)
cross bite
don’t lingualise occlusion - specialised
should you use a facebow?
no
RCP
a reproducible maxillomandibular relationship in edentulous pt
guided occlusal relationship at the most retruded (superior posterior) position of the condyles in the joint cavities
tongue back as far as possible and bite together
why is RCP reproducible?
because when condyle is retruded it can only do the hinge movement, can’t rotate - reproducibility
why not wax for jaw reg?
once you have recorded it it is set and you can’t open it
often it is good to put blocks back in mouth and see if the bite recording paste corresponds to their teeth
what are cuspless teeth good for?
pts who don’t have a reproducible bite, C3s
what are hybrid teeth good for and what is their degree?
12
complete dentures, a bit of articulation
what teeth aren’t used for complete dentures?
cusped (33)
too high
alma gauge
measure original denture and compare to rim
biometric principles - trying to set teeth in pre-ext position
incisors set 9-10mm anterior to incisive papilla
used to determine the vertical and horizontal position of anterior teeth relative to a point on the denture base e.g. incisive papilla
upper record block dimensions
height - anteriorly 22mm, posteriorly 18mm width - anteriorly 5-7mm, posteriorly 8-10mm rims set buccal to residual ridge
lower record block dimensions
height - 18mm
posterior height is 2/3 height of RM pad
width - 10mm
position over the ridge
incisive papilla and positioning anterior teeth
distal of papilla to labial aspect of 1s approx 10mm
a line extended horizontally from the distal of the incisive papilla at RAs to the median sagittal plane will indicate the position of the centre of the canine
setting posterior teeth
centre of lower alveolar ridge line transferred to occlusal surface of rim
contour of ridge drawn onto wall of cast
indicator for height of occ plane
- shouldn’t be above the RM pad
- tongue should be above the level of the occ plane to control food bolus on the surface of the teeth
last molar
do you need to include last molar or would it be bettwe to give increased space for tongue - aids stability
why is retention not as good in a tooth trial?
no post dam
assessing stability in tooth trial
check for rocking
confirm tongue lies above L occlusal plane and denture extends to RM pad
assessing extension in tooth trial
hold tissues away from denture - does it drop? - possible underextension
manipulate tissues - if drops overextension
too much lip support - will drop
make adjustments with wax knife (not fitting surface)
- hold trial so wax doesn’t drip onto acrylic teeth
assessing retention in tooth trial
frenal relief
hold tissues out way and see if denture drops
- not as good as finished denture (no post-dam)
lower occlusal plane
for most pts the level of the incisal edge is at the level of the L lip at corner of the mouth
if occ plane too high the tongue will be cramped and the denture will be unstable
tongue should rest on occ surfaces of teeth to help hold the denture in position
if OVD is increased in a tooth trial what should you do?
teeth need to be removed from one or both dentures and replaced with a wax rim if U correct - remove L teeth - replace with wax - re-record the occlusion - prescribe another wax trial
assessing occlusion in tooth trial
articulating paper
balanced - even contacts
balanced articulation - contacts on WS and NWS
protrusive contacts
centric relation (RCP) = centric occlusion in edentulous
pt view in tooth trial
comfortable?
do they feel loose?
- remember retention at trial stage reduced
appearance
- warn pt wax looks redder
speech clear?
- will move more than processed dentures but they should be retentive and stable enough to check speech
assessing speech during tooth trial
count 60-70 or days of week
assessing speech during tooth trial - if clicking
teeth make contact during speech, not sufficient inter-occlusal space between teeth
- need to reduce OVD to give more FWS
assessing speech during tooth trial - if whistling during sss
air escaping
OVD may need to be increased or anterior tooth position changed
fricatives
f, v
post dam
lip on back of denture to give good posterior seal
draw on cast where you want it w pencil
- ask technician to cut the post dam
feel for jct of hard and soft
why might you ask for a double post dam?
if pt unsure and thinks yours is too far back
one where you want it
one a bit further forward
Hanau’s Quint - 5 variables that affect occlusal contacts
inclination of occlusal plane mandibular condylar guidance (SCGA) incisal guidance angle cuspal angle compensating curve
compensating curves
allow for downward travel of the condyle
used to compensate for the difference between the CGA and the IGA (christensen’s phenomenon)
why is there often a shortened occlusal table?
because setting teeth on an inclined plane can cause instability particularly for L denture
how much of your biting strength do you lose with dentures compared to normal teeth?
75%
modify pt expectations
3 types of porosity and where can it happen?
gaseous, contraction, granular
often thickest areas e.g. L lingual
if on fitting surface need replaced
insertion stage things to check
check on models extension retention stability occlusion appearance speech
adjustments - which surface shouldn’t you trim?
fitting surface
roughness
can cause pain
extension into undercuts
can be painful - usually on insertion and removal
balance with retention
assessing denture for sore patches
can use pressure indicating paste
smooth and polish if necessary e.g. pumice and whiting
why might the occlusion need adjusted at delivery?
occ interferences occur at delivery
inaccuracy of recording RCP
limitations of articulator (av value)
ways of adjusting the occlusion at delivery
selective grinding
re-record occlusion
selective grinding
articulating paper
remember bases are unstable and denture moves
adjust carefully
palatal of anteriors - don’t take much off
BULL rule
buccal upper (palatal surface of buccal cusp) lingual lower (buccal surface of lingual cusp) adjust contacting surfaces rather than tips of cusps - appearance
re-recording the occlusion at delivery stage
clinic - check where the problem is - remove L teeth (if U is fine) - replace with wax - re-record the registration - prescribe another wax trial - give both dentures to the lab lab - remount on articulator - reset lower teeth clinic - retrial
advice for pt at delivery
pain
- if too sore wear old dentures
- if possible wear new set day before review to highlight areas of rubbing
speech
eating
- not hard diet initially - takes time to get used to
remove at night
- lets tissues breathe - less likely to get thrush
dry mouth?
- will affect retention, always put denture in moist
denture cleaning
denture cleaning advice
remind them to clean fitting surface
toothbrush and toothpaste twice a day
- not abrasive
chemical cleaners - soak for 20mins
methods of retaining an upper denture
muscular
adhesion cohesion
post dam
extension to buccal sulcus and peripheral seal
restoring FWS in v worn dentures
occlusal pivots
OR
restore occlusal surface with autopolymerising acrylic resin (provisional)
what is a knife edge ridge?
rapid resorption of lingual and buccal alveolar bone with a hard bony presentation with thin gum overlying it
causes of a knife edge ridge
traumatic XLA
severe PDD before XLA
immediate dentures
management of a knife edge ridge
soft lining
surgical removal of sharp bony spots if painful
soft lining vs tissue conditioner
soft lining - may be used on healthy mucosa as a cushion/shock absorber in a reline or for atrophic/knife edge ridges
tissue conditioner - used in unhealthy/ulcerated mucosa to aid healing. It also dissipates forces but is a more short term option
functional impression
used with a tissue conditioner
the material is applied and the pt wears the denture and impression in function for approx 24hrs
they return and the impression is sent to the lab for a reline
ways of improving denture retention without remaking them
rebase reline trim any overextensions implant retained precision attachments - tooth only supported dentures
checking retention clinically
‘pull’ on premolars
push on anteriors to check post dam
consequences of an incorrect OVD
angular cheilitis
TMD
clicking when speaking
c albicans virulence factors
germ tube formation adherence acidic metabolites EC enzymes switching mechanism
post dam
hamular notch to hamular notch
along vibrating line which is jct of hard and soft palate and is compressible tissue
1-2mm anterior to palatine fovea
why is the buccal shelf used for support?
it is relatively resistant to resorption
4 things that make up shade
value
chroma
hue
translucency
Watt and McGregor Biometric Guidelines
Set Upper teeth anterior to the residual ridge
Incisors should be 8-10mm anterior to the incisive
papilla
Set Lower teeth on the residual ridge
2mm of the incisal edge should show when at rest
Set teeth so BULL rule of ICP applies (Buccal Upper
Lingual Lower)
