Impressions and Occlusion for Complete Dentures Flashcards
what is the first clinical stage
impressions - make special trays
how big is a spacer normally
3mm
what is the second clinical stage
master impressions - master casts and record blocks
what is the third clinical stage
jaw reg
choose shade, mould and setting
mount casts and set up
what is the fourth clinical stage
try in - retry or finish
what are the try in checks
vertical dimension of occlusion
even contact in RCP
lip support
occlusal planes - anterior/posterior
lower teeth over ridge
speech
retention and stability
base extensions
appearance
what is the fifth clinical stage
insertion (finish)
what is the insertion checks
vertical dimension of occlusion
even contact in RCP
speech
retention and stability
base extensions
appearance
comfort
what is the sixth clinical stage
review
what are the review checks
pain/redness/ulceration
function
aesthetics
speech
recheck occlusion/vertical dimension
how do you know if an impression tray is too small
flanges hit the ridge
how do you know if an impression tray is too large
stretches the mouth or feels uncomfortable or cannot get it in the mouth
what are the limitations of stock trays
rarely fit mouth accurately
often require modification
difficult to obtain necessary border seal
how do you evaluate the impression
general adaptation and surface detail
appropriate sulcus depth and shape
ensure ridge is in centre of tray
appropriate landmarks included
anterior lingual sulcus
impression fixed to tray
what are special trays made in
light cure acrylic resin
what are advantages of special trays
need less impression material
custom made
ensures even thickness of impression material
less bulky
what are tissue stops used for
ensure uniform thickness of impression material
help localise tray during impression taking
where do you place tissue stops in upper and lower trays
upper - place in canine region and along post dam area
lower - place in canine region and over retromolar pads
what is used to make tissue stops
greenstick or incorporated into tray in acrylic
when are finger rests used
in lower special trays
where are finger rests placed
in region of 2nd premolar/1st molar
what do finger rests allow
fore finger to be placed on either side of tray, thumb under mandible for support to ensure it is fully seated posteriorly and ensure more even distribution of pressure to the tissues
helps stabilise tray in mouth
what is mucocompression
pressure is applied to the mucosa so that the shape of tissues under load is recorded
what is mucostasis
minimum pressure is applied to the tissues to record their shape at rest
what technique do you do avoid compression of flabby ridge
use impression with perforated tray with both high and low viscosity material
what are the 3 types of record block
wax block only
shellac base
heat cured base
what is the equipment used for jaw reg
no air/hot plate/bunsen
wax knife/palate knife
foxes bite plane
willis bite gauge/callipers
tooth shade and mould guide
bite registration paste
what does LIMBO stand for
lip support
incisal level
midline
buccal corridor
occlusal plane
when do you use LIMBO
when adjusting the upper record block for tooth position
what is the recommended nasiolabial angle
90 degrees
what do you use to check tooth position
alma gauge
what do you use to check incisal level
visual judgement
photographs of natural teeth
lip level
lip during speech
age
1-2mm of show
what should you get the patient to do when checking incisal level
fricatives
what lines are marked onto the record block
lip line, canine line, midline line
what is the buccal corridor
space between teeth and buccal mucosa shown when smiling
what references do you look for when looking at the occlusal plane
interpupillary
ala-tragus
what is the neutral zone
space between lips and cheeks on one side and tongue on other
where should the teeth be in the neutral zone
anterior teeth = over ridge
posterior teeth = over ridge
what happens if the teeth and buccal flange are too close to the cheek
dislodges denture with cheek movement
what happens if the teeth are too lingually placed
poor tongue space and tongue lifts denture when it moves
what happens if the lingual flange is an incorrect shape
tongue lifts denture when it moves
what is retruded contact position
guided occlusal relationship occurring at the most retruded position of the condyles in the joint cavities
what is muscular position
position of closure produced by balanced muscle activity raising the mandible from rest to initial contact
what is occlusal vertical dimension
distance between a set point on the maxilla and a set point on the mandible when the teeth are in maximum intercuspation
what is the resting vertical dimension
when the mandible is at rest with patient upright
what can affect the RVD measurement
stress
pain
anxiety
tensing of facial muscles
what should the ideal freeway space be
2-4mm
what would be the effects of excessive FWS
reduced masticatory efficiency
overclosed facial appearance and cheek biting
TMJ symptoms
what would the effects of reduced FWS be
excessive load on denture bearing area
continuous muscular activity results in pain
aesthetic complaints
noisy dentures
how do you measure vertical dimension
willis bite gauge
what are the final checks before recording registration
are blocks trimmed se teeth will be in neutral zone
even contact with upper block?
OVD correct for patient with adequate FWS
centre line correct
occlusal planes appropriate
