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complete dentures Flashcards

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1
Q

anatomical effects of edentulism

A

bone resorption - max rate first 3m
profile changes
loss of muscular support
reduction in face height

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2
Q

physiological effects of edentulism

A 
reduced incising efficiency
reduced masticatory efficiency
loss of proprioception
reduced swallowing efficiency
reduced speech quality
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3
Q

average bone loss - incisors

A

6.5mm

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4
Q

average bone loss - canines

A

8.5mm

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5
Q

average bone loss - premolars

A

10.5mm

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6
Q

average bone loss - molars

A

12.5mm

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7
Q

design principles

A 
retention
extension
support
stability
aesthetics
occlusion
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8
Q

how many classes in Cawood and Howell ridge classification?

A

6

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9
Q

Cawood and Howell ridge classification - 1

A

dentate (pre-ext)

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10
Q

Cawood and Howell ridge classification - 2

A

immediate post-ext

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11
Q

Cawood and Howell ridge classification - 3

A

high well-rounded broad alveolar process

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12
Q

Cawood and Howell ridge classification - 4

A

knife edge ridge (painful loading)

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13
Q

Cawood and Howell ridge classification - 5

A

flat ridge (no alveolar process) low well rounded

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14
Q

Cawood and Howell ridge classification - 6

A

submerged ridge (loss of basal bone) depressed

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15
Q

U denture extension

A 
sulcus depth all way round
avoid frenal attachments
extend to vibrating line
 - jct HP/SP
 - 1-2mm anterior to palatine fovea
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16
Q

L denture extension

A

sulcus depth all way round
avoid frenal attachments
2/3 onto RM pad

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17
Q

retention

A

resistance to vertical displacement of the denture away from the edentulous ridge

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18
Q

what is retention provided by?

A

accurate fit
border seal
retromylohyoid area (L)

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19
Q

support

A

resistance to vertical displacement of the denture towards the denture bearing tissues

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20
Q

U support areas

A

residual ridge

HP

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21
Q

L support areas

A

residual ridge
buccal shelf
anterior 2/3 RM pad

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22
Q

stability

A

resistance to horizontal displacement of denture

L often significantly worse

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23
Q

achieving stability

A 
adequate extension
using retromylohyoid area
balanced occlusion
utilising muscular forces in neutral zone
 - lips and cheeks from outside
 - tongue from inside
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24
Q

aesthetics - tooth shade

A

translucency
value
hue
chroma

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25
aesthetics - profile
lip support | creating a normal lat view of the pt
26
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 ```
27
OVD definition
height of the face from the lower border of the nose to immediately underneath the chin when the teeth are together
28
overly increased OVD
TMD poor masticatory efficiency speech problems facial pain over masseter
29
inadequate OVD
angular cheilitis occlusal trauma clicking teeth
30
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
31
FWS
difference between OVD and RVD | should be 2-4mm
32
EO exam
``` face shape profile changes smile line nasolabial angle ```
33
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 ```
34
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
35
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
36
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
37
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
38
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
39
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
40
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
41
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
42
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
43
jaw registration 5th stage
registration make 2 location notches in the premolar region to allow them to be accurately articulated Jetbite
44
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)
45
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
46
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 ```
47
tooth trial - retention
pull sharply down on anteriors | get pt to raise tongue for L
48
tooth trial - extension
check fct sulcus filled postdam included no uncomfortable overextensions/loose underextensions
49
tooth trial - support
push down on occlusal surfaces of teeth should displace slightly but not overly so look for bony spicules and relieve
50
tooth trial - stability
grab molars and move side to side use retromylohyoid area to maximise this neutral zone respected?
51
tooth trial - aesthetics
``` pt happy? profile midlines smile line buccal corridors ```
52
tooth trial - occlusion
mandibular occlusal plane at level of RMP practice in retruded arc of closure even contacts
53
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
54
delivery
do same checks as tooth trial any trimming give denture advice sheet review in 2wks
55
looseness - adjusting the fitting surface
rebase reline - hard: chairside or lab - soft: tissue conditioner or soft
56
hard reline
chairside - butylmethacrylate (non-irritant) | lab - PMMA
57
tissue conditioner
``` infected tissue helps healing can do fct impression by keeping it in for 24hrs short term 2-4 weeks ```
58
soft reline
``` long term pain - from bony prominences, residual monomer, RR or pathology atrophic ridge superficial mental nerve bony prominences omfs xerostomia ```
59
looseness - occlusal surface
premature contact - grind down incorrect occlusal plane - remake locked or wedged occlusion - use cuspless teeth
60
looseness - polished surface
rare but may be from tongue rubbing/cheek biting - relieve
61
general poor retention
``` reline rebase implant retained precision attachment add post dam ```
62
rebase
entire fitting surface altered with hard acrylic
63
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
64
restoration of FWS
occlusal pivots | restore occlusal surface with autopolymerising resin
65
what is a knife edge ridge?
rapid resorption of lingual and buccal bone resulting in a narrow ridge
66
reasons for a knife edge ridge
immediate dentures severe PDD before XLA traumatic surgery before XLA
67
management of a knife edge ridge
surgical removal of bony spicules | soft liner on denture
68
flabby ridge process
combination syndrome
69
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
70
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
71
advantages of immediate denture
``` maintain ST haemorrhage control reduce risk of dry socket psychological benefit aesthetics prevent ST collapse maintain muscle tone ```
72
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 ```
73
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 ```
74
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
75
basic denture hygiene advice
brush and soak every day
76
what should you do before soaking dentures?
use a soft brush and non-abrasive cleaner (not toothpaste)
77
denture stomatitis - organism
c albicans
78
denture stomatitis - aetiology
``` wearing at night poor OH diabetes immunocompromised xerostomia ```
79
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
80
what can you use for denture stomatitis if you are making a new denture?
tissue conditioner to temp reline current one
81
CHX MW for denture stomatitis
effective against fungal infections
82
denture stomatitis - what can antifungal agents be used for?
adjunct | esp to reduce palatal inflammation before taking imps for new dentures
83
first line antifungals for denture stomatitis
fluconazole capsules 50mg | miconazole oromucosal gel 20mg/g
84
fluconazole capsules dose
50mg 7 capsules x1 daily max 14 days for tx of this
85
contraindications to fluconazole
on warfarin/statins
86
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
87
contraindications to miconazole oromucosal gel
warfarin/statins
88
denture stomatitis - if fluconazole/miconazole contraindicated
nystatin oral suspension 100 000units/ml
89
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
90
maxilla - limiting structures
``` labial frenum labial sulcus buccal frenum buccal sulcus hamular notch vibrating line ```
91
maxilla - relief areas
incisive papilla palatine raphe crest of alveolar ridge palatine fovea
92
maxilla - supporting structures
rugae posterior palate tuberosity
93
limiting structures
guide optimum extension - engage max SA without enroaching upon muscle actions
94
symptoms of overextension
dislodgement of denture | soreness
95
symptoms of underextension
reduced retention, stability, support
96
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
97
supporting structures (stress-bearing areas)
most of load should be concentrated on these areas
98
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
99
labial sulcus boundaries
teeth, gingiva and residual alveolar ridge lips runs between buccal frenums
100
buccal frenum
fibrous band covered by MM | need greater clearance (shallower and wider) than labial frenum
101
buccal frenum attachments
levator anguli oris orbicularis oris buccinator
102
buccal sulcus location
buccal frenum to hamular notch
103
size of buccal sulcus vestibule depends on:
contraction of buccinator position of mandible amount of bone loss in maxilla
104
hamular notch
depression between distal of tuberosity and hamular process of MP plate soft area of loose CT
105
where should the distal border of the U denture extend and why?
hamular notch | helps with posterior palatal seal
106
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
107
identifying the vibrating line
ask pt to say ahhh | mark with pressure indicating paste
108
vibrating line and palatine fovea
vibrating line usually 2mm in front of palatine fovea
109
importance of vibrating line
denture needs to extend here to get seal
110
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
111
palatine fovea
2 depressions approx 2mm behind vibrating line
112
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
113
maxilla primary supporting area
posterior palate
114
maxilla secondary supporting areas
rugae | tuberosity
115
lower labial frenum
fibrous band with CT labial of residual ridge to lip helps in attachment of orbicularis oris sensitive - labial notch
116
mandible - limiting structures
``` lingual frenum labial frenum labial sulcus buccal frenum buccal sulcus alveololingual sulcus retromolar pad ```
117
mandible - supporting areas
buccal shelf | residual alveolar ridge
118
mandible - relief areas
genial tubercle mylohyoid ridge torus mandibularis
119
which muscle is active in the lower labial sulcus region?
mentalis
120
lower buccal frenum
attaches fibres of buccinator | relieve - prevent denture displacement
121
lower buccal sulcus
buccal frenum to outside back corner of retromolar region
122
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
123
lingual frenum
attaches tongue to alv process | relief
124
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
125
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
126
genial tubercle
muscle attachment - genioglossus and geniohyoid lies away from crest of ridge prominent in resorbed ridges - relief needed
127
torus mandibularis
abnormally bony prominence bilaterally on lingual side near premolar area thin mucosa - relieve
128
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
129
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
130
residual alveolar ridge mandible
secondary supporting area | buccal and lingual slopes are secondary areas
131
retromylohyoid space
distal end of lingual sulcus posterior to mylohyoid muscle aids retention and stability - can't get sideways movement - often a small UC
132
where is the loss of bone more significant?
in the mandible
133
maxilla alveolar ridge resorption
anteriorly - resorbs palatal direction | posteriorly - narrows palate
134
mandible alveolar ridge resorption
anteriorly - more vertical posteriorly - down and out, widens mandible - often make dentures with a CB
135
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
136
psychological factors of edentulism
``` relief of no more teeth lost limb syndrome embarassment denial (partner doesn't know) depression ```
137
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
138
objectives
provide adequate masticatory fct restore natural appearance restore normal speech comfort and preservation of supporting structures
139
parts
base flange border teeth
140
surfaces
fitting polished occlusal
141
factors affecting success
retention stability support physiologic comfort psychological comfort longevity
142
testing retention
pull vertically on anterior teeth away from tissues | care not to tip by uneven forces
143
aspects which lead to good retention
fit - no space between border seal - flanges, postdam no interference with muscle/frenal attachments
144
factors affecting retention
physical anatomical physiological mechanical
145
physical factors affecting retention
adhesion cohesion atmospheric pressure gravity
146
adhesion
the forces of attraction existing between dissimilar bodies in close contact (between saliva and denture base)
147
cohesion
forces of attraction existing between similar bodies in close contact (surface tension of saliva)
148
atmospheric pressure
the physical factor of hydrostatic pressure due to the weight of the atmosphere on the earth's surface
149
gravity
works against Cu, and for Cl
150
anatomical factors affecting retention
shape of the edentulous area undercuts anatomy of the border tissues
151
anatomy of maxilla class 1
square
152
anatomy of maxilla class 2
V
153
anatomy of maxilla class 3
flat
154
physiological factors affecting retention
NM control | viscosity and volume of saliva
155
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
156
testing stability
place fingers on occ surface and try to rock the denture side to side
157
tx options
``` Cu and Cl Cu or Cl - most common Cu and lower teeth nothing implant supported removable prosthesis implant supported fixed prosthesis ```
158
stages in conventional dentures
``` assessment of pt and dentures, primary imps master imps jaw reg tooth trial delivery review ```
159
stages in replica dentures
``` assessment of pt and dentures, replica imps master imps and occlusion (same visit) try in delivery review ```
160
pt assessment of dentures
``` age of dentures denture hygiene appearance movement comfort speech chewing biting satisfactory/unsatisfactory ```
161
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 ```
162
tissue adaptation
shouldn't see spaces between mucosa and fitting surface of denture
163
where should U teeth be set?
slightly buccal and labial to the ridge | tongue space and prevent stress and fracture of base
164
where should L teeth be set?
over ridge as ridge resorbs straight down
165
too much FWS
overclosure, more prone to angular cheilitis
166
too little freeway space
speech, TMJ, pain over denture-bearing area
167
ideal articulation
group fct - contact and balance both sides
168
neutral zone
musculature either side is equal
169
materials for primary imp
alginate (impression compound) silicone
170
alginate pros and cons
cheap, easy to use, elastic, quite accurate | can be messy, poorish dimensional stability - need to pour quickly
171
impression compound - what should it not be used for?
dentate pts - except e.g. for a FES | because non-elastic
172
imp compound pros and cons
poor surface detail - only for primary imps not cheap anymore can be messy
173
silicones
``` dimensionally stable hydrophobic consistencies - light, med, putty can be messy to use v accurate ```
174
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
175
ZOE
mainly historic thick not elastic mucocompressive - good for posterior flabby ridge
176
reversible hydrocolloid (agar)
mostly historic | lab for duplicating casts
177
impression definition
a reverse/negative form of the tissues which is converted into a positive model/cast using plaster or stone
178
correct sized primary tray
fully engages over alveolar ridge and depth of tray comes fully into sulcus
179
adhesive
2-3mm beyond edge of tray on the external surface
180
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?
181
trying in the U special tray - what to do if it is under/over extended
over - reduce extension | under - correct during border moulding
182
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
183
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
184
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
185
assessing your master imp
same as primary good functional sulcus? good surface detail?
186
modifying a denture with the replica technique
temp modify the old dentures with GS
187
prescription for replica dentures impressions
replica blocks in wax/shellac | - shellac base, wax polished and tooth surfaces
188
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
189
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
190
what material is used for the spacer?
wax
191
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
192
disadvantage of silicone putty compared to GS for border moulding
silicone can't be refined
193
gagging tips
open mouth wide breathe through nose wiggle toes
194
how should you place material in tray to prevent any air getting in and causing blows?
keep tray close to material dispenser
195
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'
196
advantages of impregum over silicone
fixotropic - runs when border moulding but holds shape when not hydrophillic slightly thicker
197
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
198
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
199
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 ```
200
how to mark canine line
use floss down from canthus of eye, ala of nose and down
201
arch and buccal corridor
broad arch = small buccal corridor narrow arch = broad buccal corridor how much tooth gets seen
202
overbite
want shallow | if too deep, when protrude dentures will rock against each other - displaced
203
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
204
should you use a facebow?
no
205
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
206
why is RCP reproducible?
because when condyle is retruded it can only do the hinge movement, can't rotate - reproducibility
207
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
208
what are cuspless teeth good for?
pts who don't have a reproducible bite, C3s
209
what are hybrid teeth good for and what is their degree?
12 | complete dentures, a bit of articulation
210
what teeth aren't used for complete dentures?
cusped (33) | too high
211
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
212
upper record block dimensions
``` height - anteriorly 22mm, posteriorly 18mm width - anteriorly 5-7mm, posteriorly 8-10mm rims set buccal to residual ridge ```
213
lower record block dimensions
height - 18mm posterior height is 2/3 height of RM pad width - 10mm position over the ridge
214
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
215
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
216
last molar
do you need to include last molar or would it be bettwe to give increased space for tongue - aids stability
217
why is retention not as good in a tooth trial?
no post dam
218
assessing stability in tooth trial
check for rocking | confirm tongue lies above L occlusal plane and denture extends to RM pad
219
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
220
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)
221
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
222
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 ```
223
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
224
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
225
assessing speech during tooth trial
count 60-70 or days of week
226
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
227
assessing speech during tooth trial - if whistling during sss
air escaping | OVD may need to be increased or anterior tooth position changed
228
fricatives
f, v
229
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
230
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
231
Hanau's Quint - 5 variables that affect occlusal contacts
``` inclination of occlusal plane mandibular condylar guidance (SCGA) incisal guidance angle cuspal angle compensating curve ```
232
compensating curves
allow for downward travel of the condyle | used to compensate for the difference between the CGA and the IGA (christensen's phenomenon)
233
why is there often a shortened occlusal table?
because setting teeth on an inclined plane can cause instability particularly for L denture
234
how much of your biting strength do you lose with dentures compared to normal teeth?
75% | modify pt expectations
235
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
236
insertion stage things to check
``` check on models extension retention stability occlusion appearance speech ```
237
adjustments - which surface shouldn't you trim?
fitting surface
238
roughness
can cause pain
239
extension into undercuts
can be painful - usually on insertion and removal | balance with retention
240
assessing denture for sore patches
can use pressure indicating paste | smooth and polish if necessary e.g. pumice and whiting
241
why might the occlusion need adjusted at delivery?
occ interferences occur at delivery inaccuracy of recording RCP limitations of articulator (av value)
242
ways of adjusting the occlusion at delivery
selective grinding | re-record occlusion
243
selective grinding
articulating paper remember bases are unstable and denture moves adjust carefully palatal of anteriors - don't take much off
244
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 ```
245
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 ```
246
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
247
denture cleaning advice
remind them to clean fitting surface toothbrush and toothpaste twice a day - not abrasive chemical cleaners - soak for 20mins
248
methods of retaining an upper denture
muscular adhesion cohesion post dam extension to buccal sulcus and peripheral seal
249
restoring FWS in v worn dentures
occlusal pivots OR restore occlusal surface with autopolymerising acrylic resin (provisional)
250
what is a knife edge ridge?
rapid resorption of lingual and buccal alveolar bone with a hard bony presentation with thin gum overlying it
251
causes of a knife edge ridge
traumatic XLA severe PDD before XLA immediate dentures
252
management of a knife edge ridge
soft lining | surgical removal of sharp bony spots if painful
253
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
254
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
255
ways of improving denture retention without remaking them
``` rebase reline trim any overextensions implant retained precision attachments - tooth only supported dentures ```
256
checking retention clinically
'pull' on premolars | push on anteriors to check post dam
257
consequences of an incorrect OVD
angular cheilitis TMD clicking when speaking
258
c albicans virulence factors
``` germ tube formation adherence acidic metabolites EC enzymes switching mechanism ```
259
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
260
why is the buccal shelf used for support?
it is relatively resistant to resorption
261
4 things that make up shade
value chroma hue translucency
262
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)

dentures (2 decks)

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