Prosthodontics Flashcards
common types of denture fracture
midline
tooth detaches from denture base
loss of flange
acrylic saddle detaches from Co/Cr baseplate
clasp fracture/bent
give reasons why a denture may fracture?
impact
acrylic in thin section
work hardening of metal
parafunctional habits
occlusion - deep overbites
soft linings
denture processing problem - porosity
bonding between tooth and base acrylic, or acrylic and CoCr
Give an example of a situation when you could carry out a simple denture repair
if the fractured pieces can be located together
- e.g. midline fracture of complete denture
how would you carry out a simple denture repair
disinfect fractured pieces
send to lab;
- cast poured
- fractured area removed
- new acrylic processed
how would you repair a denture fracture where a piece of the denture is missing?
take an impression with the fractured denture in the mouth
disinfect and send to lab
- cast poured
- new acrylic processed into defect
name 3 strengtheners that can be used in denture repairs
wire mesh
glass-fibre mesh
stainless steel wire
Reasons why patients may be dissatisfied with dentures
related to denture retention and stability
- usually lower denture
Patient may not be aware of limitations
aesthetic expectations unmet
decreased chewing efficiency
change in facial aesthetics due to tooth loss
Examination of denture bearing area - things to look our for
severely resorbed ridges
flabby ridges
tori
prominent mentalis muscles, mylohyoid ridge, genial tubercles
high muscle attachments
pain on ridge palpation
retching patients - management
identify problems
identify trigger zones
reduce anxiety
patience and empathy
distraction techniques for impression taking
talking to patient
get patient to concentrate on keeping their leg raised/wiggle toes
get patient to press or tap on their temple
salt on patients tongue
ask patient to close eyes
rinse mouth with very cold water just before treatment
desensitisation techniques for retching patient
repeated brushing or stroking anterior palate or tongue with finger or toothbrush
“homework” of bushing/stroking for patient pre-treatment
swallowing with mouth open
hypnosis
CBT
What is the MAGIC technique?
main amelioration of gagging indoctrination by communication
- patient fills their lungs completely with air
- sends a strong message form lung stretch receptors to medulla oblongata that there is plenty or air and no risk of choking
- psychogenic gag reflex is subverted
how to modify impression taking for retching patient
modify stock trays
lower trays in upper arch
palatal reduction on special tray
rapid setting materials
- e.g. alginate with warmer water = reduced exposure time
securing an implant denture firmly - options
locator abutments
ball abutments
gold bar
CAD-CAM titanium bar
common post implant treatment complications
peri-implant mucositis
peri-implantitis
loose/fractured components
late implant failure
2002 McGill consensus conclusion
a 2 implant over denture should be the first choice of treatment for the restoration of the edentulous mandible over the conventional denture
Complete upper denture opposing lower natural teeth - effects
presence of natural teeth mean that high levels of force can be developed against the upper mandibular alveolar ridge
leads to
- trauma to maxillary denture bearing area
- instability of denture
- fibrous ridge
How is a a fibrous ridge formed?
as a result of alveolar resorption and fibrous tissue replacement
Fibrous ridge - problems
tissue easily displaced
tipping of prosthesis
give examples of pathological changes related to dentures
ulcers
denture stomatitis
angular chelitis
denture irritation hyperplasia
flabby ridges
MRONJ/ORN
allergic reactions
causes of ulcers (denture related)
overextension; sharp bits on denture, pressing too hard, occlusal trauma
denture related ulcers - management
identify
- pressure indicating paste
- articulating paper
ease
- occlusal adjustment
- trim and polish base
review
denture stomatitis management
denture hygiene instructions
- take denture out at night
- clean with soft brush
- chlorhexidine mouthwash
- antifungals e.g. nystatin
consider underlying issues
- diabetes
- b12, folate
angular chelitis causes and features
often co-exists with denture stomatitis
result of overclosure
- loss of OVD/excessive free way space , old worn dentures
angular chelitis - management
miconazole gel (interaction with coumarins)
consider underlying issues
- diabetes
- folate
- xerostomia
- ferritin
denture irritation hyperplasia - cause
often very old, ill-fitting dentures
chronic trauma resulting in hyperplastic response
denture irritation hyperplasia, management
major ease of denture
tissue conditioner e.g. Coe comfort
review and repeat if needed
new denture?
flabby ridges - solution
new denture covering whole denture bearing area with good peripheral seal AND opposing arch denture giving posterior support
may occasionally need special impression techniques
MRNJ/ORN cause (denture related)
and ill fitting denture in a patient on anti resorptive medication
MRONJ/ORN management
refer promptly to maxfax
when to conform to existing occlusion
stable occlusion
sufficient index teeth
usually use ICP
when to change existing occlusion
lack of sufficient index teeth
often use RCP
usually more challenging to record occlusion
what materials can be used to take an interocclusal record?
bite registration paste
wax wafer
modified wax wafer
- e.g. alminax
What is the intercuspal position?
the complete intercuspation of the opposing teeth independent of condylar position
what is the retruded contact position?
guided occlusal relationship occurring at the most retruded position of the condyles in the joint cavities
When would a soft reline be appropriate?
parafunctional habits
very atrophic ridges
cancer/cleft patients (obturators)
Downsides of soft relines
plasticiser leaches
deteriorate over time
can habour microorganisms
name materials that can be used for soft linings
heat cured acrylics
self cured acrylics
heat cured silicones
self cured silicones
denture rebase technique for upper denture
undercuts removed from denture
wash impression taken with closed mouth technique
- sent to lab
Name the Kennedy classifications
Class 1 bilateral free end saddle
class 2 unilateral free end saddle
class 3 unilateral bounded saddle
class 4 anterior bounded saddle across the midline
aims of surveying casts for partial dentures
determine path of insertion
determine position and depth of undercuts using survey lines
benefits of Co/Cr denture base material
stronger than acrylic
thinner/less bulky
usually better tolerated
less destructive to periodontal tissues
disadvantages of CoCr denture base
more expensive
difficult to add to
benefits of acrylic denture base material
cheaper
easier to add to
downsides of acrylic denture base material
weaker
thicker
less well tolerated
more destructive to periodontal tissues
components of the RPI system
R - mesial occlusal rest
P - distal guiding plate
I - I bar clasp
where would the RPI system be used?
in a free end saddle
- Kennedy class 1 or 2
function of the RPI system
reduces stress on the abutment tooth
how does the RPI reduce stress on the abutment tooth?
when under load, the denture rotates towards the mucosa underlying the saddles without damaging the abutment
as saddle presses into denture bearing area it rotates around the mesial rest
distal plate and I-bar move down and away from tooth avoiding torque on the abutment tooth
care and maintenance of dentures - advice to give patients
remove dentures at night
mechanical cleansing with soap and water
- NOT toothpaste
soft brush
immersion in chemical cleaner
- variable manufacturers guidelines
- store overnight in cold water after chemical cleanser
for partials - stress cleaning of natural teeth with dentures out
Complete dentures try in checks
OVD and free way space
even contact in RCP
lip support
occlusal planes
lower teeth over ridge
speech
retention and stability
appearance
base extensions
complete denture review checks
pain/redness/ulceration
function
speech
aesthetics
recheck occlusion and vertical dimension
benefits of replica dentures
keeps existing design
maintains existing aesthetics
only 1 impression in the mouth
1 less clinical stage
downsides of replica technique
major modifications difficult
- can reproduce faults
space required for a lingual bar
8mm
- 3mm from gingival margin
- 4mm height of bar
- 1mm clearance from functional floor of mouth
benefits of bar connectors
little coverage of gingival tissue
wide relief of gingival margins to prevent food packing
rigid
downsides of bar major connectors
posterior bar offers less support to free end saddle across hard palate
greater cross sectional thickness
number of edges - some pts may find uncomfortable
benefits of plate connectors
thinner cross section
wide relief of gingival margins to prevent food impaction
support across hard palate for free end saddle
less edges - more comfortable
downsides of plate connectors
anterior plate has 3 small windows that could possibly cause food impaction
What is an immediate denture?
Any removable dental prosthesis fabricated for placement immediately following the removal of a natural tooth or teeth
Immediate denture advantages
- guide for aesthetics
- speech
- function
- self esteem
- avoid drifting/tilting or over eruption of remaining teeth
- promotes health
- better adaption to dentures
- prevents collapse of facial musculature
immediate denture disadvantages
- temporary prosthesis due to resorption
- poor adaptation to ridge very quickly
- guesstimate as to how healing will proceed
immediate denture possible contraindications
- some MRONJ cases
- pre-chemo/radiotherapy
- pathology
- fractures
Initial aftercare following immediate denture delivery
- dentures to be kept in for 24 hours
- ideally review appt on day after insertion
- after 24 hrs advise warm saline mouthwash and patient to remove dentures after mealtimes to rinse mouth and clean dentures
What are replica dentures?
a copying technique for replacement of complete dentures
stages in replica denture construction
assessment of patient and dentures
replica impressions
2nd impressions and occlusion
trial insertion visits/tooth trial
delivery
maintenance
aftercare
complete dentures - common patient complaints
appearance
eating
pain/discomfort
loose
retching
speech
dislike wearing a denture
why is RCP used in complete dentures?
most reproducible position
no opposing teeth so ICP cannot be used
define retention and stability, in relation to dentures
retention = resistance to vertical displacement
stability = resistance to lateral displacement
When would you use a temporary reline?
post immediate dentures
tissue conditioning - grossly ill fitting dentures
after implant surgery
