complete dentures Flashcards
anatomical effects of edentulism
- bone resorption
- profile changes
- loss of muscular support
- reduction in face height
physiological effects of edentulism
- reduced incising efficiency
- reduced masticatory fucntion
- loss of proprioception
- decreased swallowing efficiency
- redcution in speech quality
av bone loss
incisors
6.5mm
av bone loss
canines
8.5mm
av bone loss
premolars
10.5mm
av bone loss molars
12.5mm
Atwood and Howell
Ridge Classification
I
pre-extraction - dentate
Atwood and Howell
Ridge Classification
II
post-extraction - immediately edentulous
Atwood and Howell
Ridge Classification
III
high well rounded
Atwood and Howell
Ridge Classification
IV
knife edge ridge
Atwood and Howell
Ridge Classification
V
low well rounded
Atwood and Howell
Ridge Classification
VI
depressed
design principles for C/C denture
R etenion
E xtension
S upport
S tability
A esthetics
O cclusion
retention
definition
resistance to vertical displacement of the denture away from the edentulous ridge
retention provided by
accurate fit
border seal
retromylohyoid area - in lower jaw
extension of upper complete denture
suclus depth all way round
avoid frenal attachments
palate of denture should extend to vibrating line (junction of hard and soft palate, 1-2mm anterior to the palatine fovea)
extension of lower complete denture
sulcus depth all the way round
avoid frenal attachments
2/3 onto the retromolar pad and into the retromylohyoid area
support
definition
resistance to vertical displacement of the denture toweards the denture bearing tissues
support provided by
(upper complete)
residual ridge
hard palate
support provided by
(lower complete)
residual ridge
buccal shelf
anterior 2/3 retromolar pad
stability
definition
resistance to horizontal displacement of the denture
stability provided by
adequate extension of the denture
using the retromylohyoid area (lower)
balance occlusion
utilising the muscular forces in the neutral zone
- lips and cheeks press in from the outside
- the tongue from the inside
2 factors of C/C aesthetics
shade of teeth
- translucency
- value
- hue
- chroma
profile
- lip support
- creating a normal lateral view of the pt
Balanced Occlusion - Hanau’s Quint
C ompensating curve
O rientation of the occlusal plane
C uspal angle
C ondylar guidance angle 30o
I ncisal guidance angle 15o
Occlusal Vertical Dimension
OVD
the height of the face from the lower border of the nose to immediately underneath the chin when the teeth are together
increased OVD
- TMD
- poor masticatory efficiency
- speech problems
- facial pain over masseter
inadeqaute OVD
- angular cheilitis
- occlusal truama
- clicking teeth
RVD
resting vertical dimension
the height of the face from the lower boder of the nose to immediately underneath the chin when the teeth are apart at rest
FWS
freeway space
difference between RVD and OVD
should be 2-4mm
assess of pt for Complete dentures
History
Exam
- E/O
- ‣ Face shape
- ‣ Profile
- ‣ Changes
- I/O
- ‣ Ridge shape (Atwood and Howell)
- ‣Undercuts - spicules/irregularities
- ‣ Consistency
- ➡ Firm
- ➡ Friable (flabby)
- ➡ Jagged (knife edge)
- ‣ Tissue health
- ‣ Saliva flow and quality
- ‣ Sulcus depth
- ‣ Muscle relationships
- ‣ Skeletal relationship (AP)
primary impressions for complete denture
Assess if undercuts - this will determine material used
- ‣ If undercuts then use - Alginate (Irreversible Hydrocolloid)
- ‣ If no undercuts then use - Impression Compound (Non-Elastic)
Use the same material for Upper and Lower usually
lab prescription for primary imps to master imps
Please pour up primary impressions in 50/50 Stone and Plaster
Please construct special trays in light cure PMMA A.
- Upper - E/O handle
- Lower - I/O handles w/ stub handles over premolars
Spacer - For the material you will use at MASTERS!
- Alginate - 3mm
- Silicone/Compound
- i) Upper - 2mm
- ii) Lower - 1mm
master impression stage for complete dentures
Trim special tray
check extension
Modify trays with greenstick tracing compound (heat till it begins to droop)
- Upper - Canine stops, Post dam extension full posterior border of tray
- Lower - Canine stops, Retromolar pad
- Both - Add material to fill functional sulcus and border mould
Use Polyvinyl siloxane (Extrude) - Medium body
➡ remember that PVS is hydrophobic so will create blebs - dry mucosa!
➡ Polyether (impregum is an alternative but has one visocity but is hydrophilic)
lab prescription master imps to jaw reg
- Please pour up the secondary impressions in 100% dental stone
- Construct upper and lower wax occlusal rims on light cured bases
- Please do to post dam as marked
6 stages in jaw reg
MEASURE RESTING FACE HEIGHT AND OVD
adjust upper record block
lipline and occlusal plane
measure vertical dimension and establish face height
tooth position
registration
selection of teeth
adjusting upper record block
- Trim any overextensions otherwise will drop
- Don’t give too much lip support
- Adjust rim vertically till youre roughly happy where it is
- Don’t adjust too much so as you have working room for occlusal plane determination
lipline and occlusal plane
- use the alar tragus line (superior part of EAM and the alar of the nose (nostril squishy side bit) make parallel with foxes bite plane and also view from front and make sure foxes bite plane parallel to interpupillary line
- Determine Canine line - inner canthus of the eye with floss
- Mark high smile line here as you’re done adjusting the occlusal plane
measure vertical dimension nad establish face height
Willis bite gauge used to measure RVD and OVD
To get OVD try and replicate their RCP as this is what youll use later
- lick lips and look out window absent mindedly
- then measure RVD
- OVD should be 2-4mm less than this depending what you want your FWS to be! - are you increasing or maintaining OVD?
If you want to change FWS then adjust lower block and not the upper! youve done that already
tooth position
Biometric guidance (Watt and McGregor)
Set upper teeth buccal to the residual ridge
8-10mm anterior to the incisal papilla
Set lower teeth on the ridge
registration
Make sure cenine line, high smile line and centre line marked
Make two location notches in the premolar region of the two blocks to allow them to be accurately articulated
Use Jetbite to register together
lab prescription jaw reg to tooth trial
- please mount casts to the registration recorded on an average value articulator
- Please set the upper teeth to the record block
- Please set the lower teeth to the upper teeth.
- See shade and mould overlea
tooth trial assess
retention
extension
support
stablity
aesthetics
occlusion
retention checks at tooth trial
pull sharply down on anteriors
get pt to raise tongue for lowers
extension check at tooth trial
check that the functional sulcus is filled
post dam included
no uncomfortable overextensions or loose underextensions
support check at tooth trial
push down on occlusal surfaces of teeth
should displace slightly but not overly so
look for bony spicules and relieve
stability check at tooth trial
grab molar teeth move from side to side
use retromylohyoid area to maximise this
neutrol zone respected?
aesthetics check at tooth trial
is the pt happy with shade and mould?
profile?
midlines coincide
smile line
buccal corridors
occlusion check at tooth trial
mandibular occlusal plane at level of RMP
practice in retruded arc of closure
even contacts
lab prescription after tooth trial
to delvery
- please wax up for finish and process in heat cured PMMA
- Also Mark post dam at this stage.
IF retrial
Re-Trial: remount casts and make specified changed for second tria
delivery of complete denture
- Do same checks as Tooth trial -
Make any trimmings to it -
Give denture advice sheet (see section on Denture Hygiene) -
Review in 2 weeks
how to solve denture looseness
- Reline and Rebase
➡ Hard Reline
- Chairside - Butylmethycrylate (non-irritant)
- Lab - PMMA
➡ Soft Reline
- Tissue conditioner - infected tissue - helps healing, can do functional impression by keeping in for 24hrs (short term)
- Soft reline (long term)
✴ P - pain - from bony prominences, residual monomer, retained roots or pathology
✴A - atrophic ridge
✴S - superficial mental nerve
✴B - bony prominences
✴O - omfs
✴X - xerostomia
problem with complete denture occlusal surfaces
premature contacts = grind down
incorrect occlusal plane = remake
locked or wedged occlsuion = cuspless teeth
problem with polished surface of dentures
rare
can be from tongue rubbing or cheek biting - relieve
general poor retention of dentures solutions
reline
rebase
implant retained
precision attachment
add post dam
Replica technique
- Apply fix to fitting surface of one tray and the outside of another tray i.e the bottom
- 5x scoops of lab putty per impression, activator applied measure - 1 width of spoon mark per one scoop of putty
- Set denture into tray as you would normally and adapy putty
- Locating notches into the putty for when you do opposing impression
- Vaseline on set lab putty of first denture impression
- Put new ball of putty onto the fitting surface of denture already in impression and push really hard
- Push your second tray really hard onto this new putty (the one youve fixed on the back side)
- Match locating notches up with ones youve already done
- Take dentures out of the moulds by levering from the heel of the denture to minimise chance of fracture
- wash old dentures return to patient
- put impressions back together
- you will be given a shellac base and record block to record jaw reg next time
restoration of FWS by
occlusal pivots
restore occlusal surface with auto polymerising resin
what is a knife edge ridge
rapid resorption of lingual and buccal bone resulting of a narrow rudfe
two corries back to back
3 reasons for knife edge ridge
immediate dentures
severe periodontal disaease before XLA
traumatic surgery before XLA
management of knife edge ridge
surgical removal of bony spicules
soft liner on denture
flabby ridge
process
combination syndrome
flabby ridge
how does it occur
forces directed at upper anterior maxillary ridge covered by a denture occluding with dentate lower causes rapid resorption of maxillary ridge which, the overlying tissue becomes very fibrous and flabby
managament of 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 take impression
adv of immediate denture
- Maintain soft tissue
- Haemorrhage control
- Reduce dry socket
- Psychological benefit
- Aesthetics
- Prevent soft tissue 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
what to clean dentures with
alkaline hypochlorites
effervescent peroxides
alkaline hypochlorites
e.g.dentural, Milton
Don’t leave cobalt chromium dentures for longer than ten mins as they 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
e.g. steradent, boots effervesant original
Powder of tablets
Rapid in action and simple to use
Problems can arise if very hot water used with denture, it can cause bleaching
Additional mechanical cleansing action
Bubbles created by the release of Oxygen which may dislodge debris
oragnism involved in denture stomatitis
candida albicans
aetiology of denture stomatitis
wearing at night
poor OH
diabetes
immunocompromised
xerostomia
tx denture stomatitis
Denture Hygiene take out and clean with separate toothbrush - Alakaline peroxide for 20mins then store in water
CHX mouthwash
Miconazole gel, Nystatin
Fluconzaole, itraconazole, Ketoconazole
Tissue conditioner if youre making new denture to temporarily relive current one
