Pros textbook Flashcards
1
Q
How do missing teeth affect a patient’s facial appearance?
A
The loss of teeth causes jawbone resorption.This causes patient’s maxilla to move backwards and the patients mandible to move forwards.
2
Q
Why does alveolar resorption occur?
A
There is a lack of downwards pressure on the alveolar bone due to tooth loss which causes bone loss.
3
Q
What is the saddle?
A
The area in the mouth which has no teeth.
4
Q
What type of saddle is this?
A
A Free end saddle
There are no teeth at the end.
5
Q
What type of saddle is this?
A
A bounded saddle-
Where the gap has teeth on either side.
6
Q
Discuss tooth borne support?
A
Tooth borne is when everything rests on the teeth rather than the soft tissue.
This is the most desirable as it prevents tissue damage.
7
Q
Discuss mucosa borne support?
A
Mucosa borne support is where everything rests on the mucosa.
These dentures are replacing lots of teeth
8
Q
Describe a denture patient assessment.
A
- Full denture history- Why do they have dentures/how long for/ how many/ denture preferences.
- Medical history
- Social history
- Examination (of patient and denture seperately then together)
9
Q
Why is knowing how the patient lost their teeth beneficical for producing dentures?
A
If the patient lost their teeth due to periodontal disease this will cause the ridges to change quicker. You want to know this.
10
Q
Describe these missing teeth using kennedy class:
A
Kennedy class I
This is a bilateral free end saddle
(free end on both sides= bilateral)
11
Q
Describe these missing teeth using kennedy class:
A
This is kennedy class II.
This is a unilateral free end saddle.
12
Q
Describe these missing teeth using kennedy class:
A
This is kennedy class III.
This shows a unilateral bounded saddle.
13
Q
Describe these missing teeth using kennedy class:
A
This is kennedy class IV.
This is a anterior bounded saddle.
(The saddle crosses the midline and is surrounded by teeth)
14
Q
Describe these missing teeth using the craddock class:
A
This is Craddock class I.
This is tooth borne support.
15
Q
Describe these missing teeth using craddock class:
A
This is craddock class II.
This is mucosa borne support
This is where the vertical biting force is against the soft tissue saddle.
16
Q
Describe these missing teeth using craddock class:
A
This is craddock class III
This is mixed tooth and mucosa borne support.
1 saddle is supported by teeth, the other is a free-end.
17
Q
What are the three main things we consider when looking at dentures?
A
- Support- does the denture resist movement vertically towards the tissue? (Does the denture push up towards the tissue)
- retention- is the denture easily displaced away from the tissue? (Can the denture be moved away from the tissue easily)
- Stability- Does the denture resist horizontal movement. (Can the denture be moved from side to side?)
18
Q
What is this picture showing? and discuss it
A
This is denture stomatitis.
This is a mixed infection of bacteria and yeast caused by wearing a denture all the time. The exact shape of the denture is showing the gum at A.
19
Q
What is partial edentiulism?
A
This describes a patient with some but not all teeth missing in the arch
20
Q
What are the visits required for a denture patient?
A
Assessment and primary impressions
Master impression
May need jaw reg if using record blocks
Framework trial (RPD only)
Tooth trial
Delivery & fit
review
21
Q
What are you looking for in an examination of the patient’s mouth?
A
Ridge form (can tissue be displaced)
free end saddles
bounded saddles
Undercuts
22
Q
Compare edentate trays to dentate trays.
A
Edentate trays are shallower than dentate trays for patients without teeth
23
Q
What material(s) are used for an impression with free end saddles?
A
Alginate and compound
24
Q
What material(s) are used for an impression without free end saddles?
A
alginate
25
How do we take a compound impression?
The compound takes an impression of the saddle areas.
Any compound impressions containing teeth should be cut away.
26
What is the alginate wash?
This is a thin layer of alginate that is applied over the compound to take the full impression.
We use an adhesive to attach the compound to the alginate.
27
How do we prepare an impression for the lab?
The impression is disinfected in perform for 10 minutes.
It is then placed in a bag with wet cotton wool to prevent the alginate from drying out.
28
Summarise what happens in visit 1?
We examine the patients mouth
Take the primary impression
Measure the occlusion.
29
What do you do once the lab produces the primary cast?
You check if you can hand articulate the primary cast or not.
If you can hand articulate the cast, then you can begin the denture design & request the special tray design.
If you cannot hand articulate the cast then we need primary record blocks to record the patient's jaw registration .
30
What do you need to do before the second visit?
Survey the cast- find undercuts and alter path of insertion
Decide if any modifications are needed (rest seats/ guideplanes/ undercuts)
Draw the design.
31
Compare the different choices for impression materials:
Medium bodied silicone (do not want the patient swallowing this)
Polyether (very rigid so you don't want to use it with undercuts)
Alginate (good with undercuts)
Impression compound (used for saddle areas)
32
How do we take the master impression?
1. Try in the special tray and trim it if the tray is over extended
2. Modify the tray with compound for the free end saddles/ any underextended areas
3. Apply adhesive to the special tray and use chosen material to create the impressions.
4. Disinfect the impression material.
33
What instructions should you give the technician if you are producing a cobalt chrome denture?
The model should be poured in improved stone.
Chrome framework should be constructed as per the design.
If self articulating -
Use registration provided to mount casts
Set upper teeth to lowers with minimal overjet and overbite
Use___ (shade) and ____ mould.
Any special instructions e.g. diastema.
If not self articulating (construct occlusal wire strengthened wax rims on light cured bases for the jaw registration)
34
What instructions should you give the technician if you are producing an acrylic denture?
The model should be poured in 100% dental stone
A record block with an arylic base should be produced.
If self articulating -
Use registration provided to mount casts
Set upper teeth to lowers with minimal overjet and overbite
Use___ (shade) and ____ mould.
Any special instructions e.g. diastema.
If not self articulating (construct occlusal wire strengthened wax rims on light cured bases for the jaw registration)
35
What do you check with the framework?
Does the framework fit the cast?
Does it seat correctly?
Is the cast damaged at all?
Does the framework interfere with occlusion?
36
Why do we record the occlusion?
To help design the denture
To help the technician set up the teeth
To ensure stability of the denture and patient comfort
Ensure loading forces are correctly applied to the teeth.
37
What instructions and information do you give the technician after the framework trial
Instructions: To articulate your casts to registration so you can complete a tooth trial
Information:
* The type of articulator you want your cast aligned on.
* To articulate your casts to registration so you can complete a tooth trial.
* where you want the artifical teeth to be positioned.
* The shade of artificial teeth needed.
* How the teeth occlude.
38
What are you checking for in the tooth trial?
Check dentrue outside the mouth
* Does the articulating pin touch the plate- if not what’s stopping it?
* Does the framework fit the cast?
* The occlusion- are there any contacts (articulating paper)
* Are there any sharp edges?
* How does the denture look aesthetically?
Try denture in :
* Occlusion
* Retention
* Extension
* Satbility
* Speech
* Aesthetics
* Comfort
39
What are you looking for in the denture on the articulator?
Is the design as requested?
Is there any roughness or bubbles on the denture?
Does the denture seat properly?
Are there any broken teeth on the cast (this would provide undercuts )
Is the pin on the table of the articulator?
Does the occlusion look correct?
40
What are you looking for in the denture on the patient?
Extension- is denture impinging on frenal area?
Does it drop when Pulling away tissues (underextended)
Does. itdrop when manipulating tissues (overextended)
Stability (does it rock from side to side)
support-Are the rests and flanges sitting accurately?
Retention- do the clasps need adjusted?
Aesthetic- what does the patient think?
Occlusion- do the teeth meet in the prescribed occlusion and are there any heavy contacts?
Speech- Is this affected? We can reduce the denture thickness.
Does the denture sit properly?
41
What instructions do you give a denture patient?
* That the denture will need to be worn in
* That it will affect speech and eating
* How to clean the denture
* Refer the patient to the clinic patient leaflet.
42
What is the difference between impression compound and greenstick?
Impression compound is used for modification of the trays during the first impressions- if there are free end saddles.
Greenstick compound is used to modify the special trays.
43
What is the part of the denture that the arrow is pointing to?
This is the denture flange and it is the replacement tissue which extends into the vestibular sulcus
44
Why can kennedy class IV not have a modification?
As the most posterior saddle defines the classification. Therefore, if the patient had another saddle it would be used for classification & the kennedy class IV would be reffered to as the modification.
45
Compare denture support?
Using teeth for support directs the load through the PDL of the abutment teeth.
Using mucosa for support distributes the load over a wide area. This uses the hard palate and saddles.
46
Which tooth should we pick to provide support
Those teeth with the largest root area.
47
What is a denture rest?
This is the metal bit attached to the tooth that allows distribution of the load down the abutment teeth.
48
What are the functions of the rest?
* Preventing movement of the RPD towards the mucosa
* Distributing the occlusal load
* Supporting the placement of clasps
* Preventing the over-erruption of unopposed teeth
* Providing bracing on the anterior teeth
* Determining the axis of rotation for free end saddle RPDs.
49
What is important when designing an occlusal rest?
The rest should come down to the midline of the tooth. So it is large enough for the force goes down the long axis of the tooth .
It should not be placed on an occlusal contact point (as this would be very uncomfortable for the patient)
50
What is important for incisal rest design?
An incisal rest should only be used on the lower arch (it is unaesthetic on the upper)
51
What is an advantage of a cingulum rest?
The cingulum rest applies the stress at a lower level.
This means there is less rotational force, meaning the tooth is less likely to break.
52
Why is it rare to have a metal rest in an acrylic denture?
The metal rest is encorporated mechanically to the acrylic base which produces a pottential weak point in the denture (leading to denture failure)
53
Where do we place rests on a bounded saddle?
On either side of the saddle area
54
Where do we place rests on a free end saddle?
The opposite side of the tooth to the saddle.
This is to prevent torquing
55
Why is having a small surface area of mucosal support inadvisable?
As it will place pressure at the gingival margin and acclerate bone resorption causing denture failure.
56
Why are mucosa only dentures not recommended on the lower arch?
As the mucosal support on the lower arch is limited.
You can only use the buccal shelf.
57
What is an 'every' RPD design?
This is an open designed denture which spreads the load and keeps the gingival margins healthy.
The denture is kept in the mouth by the frictional contacts between the artificial teeth and the abutment teeth.
58
What is the arrow pointing to in this denture and what is the function?
The arrow is pointing to wire stops.
These prevent distal drift of the posterior teeth.
We want to prevent this drift as it would cause the loss of the frictional contacts resulting in the denture falling out.
59
What is Axial Torque?
When movement of the tooth one way causes the root to move the other. This causes breakdown of the Periodontal ligament.
60
What can we do if the chosen rest position is an occlusal contact point?
* We can move the rest onto the opposite side of the tooth
* Complete a preparation for the rest (requires drilling into a healthy tooth)
61
What is retention?
What prevents the denture from being dislodged.
62
Compare the two types of retention?
**Direct retention**- prevents vertical displacement of the denture.
**Indirect retention**- prevents rotational displacement of the denture.
63
How can we achieve retention?
* **Mechanically**- using clasps
* **Muscular forces** (over time lingual and buccal muscles will hold the denture in place)
* **Physically**- using
Adhesion- saliva on the denture
Cohesion- substances within saliva
* Through **frictional** contacts.
64
What are guideplanes
Guideplanes are paralell surfaces that provide frictional contacts.
65
What are clasps?
A metal arm that contacts the tooth in an undercut in order to prevent the removal of a denture base.
66
Compare guideplanes to clasps
Guideplanes don't deform over time giving you long term retention.
Clasps deform.
67
How does the clasp move into place?
The clasp deforms over the bulbosity of the tooth.
68
How does a rest help clasp function?
The rest prevents the clasp slipping down and damaging the tooth or gingival margin.
69
Where do you find the undercut on upper posterior teeth?
On the buccal.
70
Where do you find the undercut on lower posterior teeth?
The lingual.
L-lower L-lingual
71
Describe an occlusally approaching clasp.
This clasp comes to the undercut across the occlusal surface of the tooth.
It is used for molars.
72
What is a gingivally approaching clasp
This comes to the tooth crossing the gingival margin. (It comes from the sulcus)
It is used for anterior teeth, canines and premolars.
(It is also known as an I-bar clasp.
73
Why do we use a gingivally approaching clasp for the anterior teeth, canines and premolars?
It is the only way we can guarentee the 15mm of length that is needed in order to achieve retention.
74
What is a self reciprocating clasp?
This is a clasp where the clasp metal extends to where the reciprocal arm would be.
75
Describe the function of the reciprocal arm.
The clasp arm applies a horizontal force to the tooth when it comes in contact.
The reciprocal arm is also in contact on the opposite side.
The reciprocal arm counteracts the force to prevent tooth movement when the clasp is flexing over the bulbosity.
76
Why do we aim for a triangular patten of retention?
So that you will always have one retainer preventing the dislodging of the plane of the other 2 retainers.
77
What is the RPI?
A stress relieving clasp system used to prevent stress on the last abutment tooth of a lower free-end saddle.
78
What are the components of the RPI?
**A**- Rest (an occlusal rest on the mesial)
**B**- Proximal plate (placed adjacent to the saddle)
**C**- I bar clasp
79
How does the RPI clasp prevent pressure?
The I bar and the proximal plate rotate downward and mesially to come out of contact with the tooth when the patient chews.
This reduces the pressure being applied to the tooth and avoids torque.
80
How do we achieve indirect retention for free end saddles?
By moving the supporting element away from the saddle area at 90º from the clasp axis
81
What provides indirect retention?
* Major connectors
* minor connectors
* saddle
* rest
* denture base
82
What is the connector?
The rigid part of the partial denture that unites the other components.
83
What is a minor connector?
Thes join components such as rests to other components and the major components.
84
What is the function of the minor connector?
They transfer functional stresses to and from the abutment teeth.
85
What should you expect in a minor connector?
It should finish above the survey line on teeth
It should cross the gingvial margin at right angles.
It should cover as little gingival margin as possible.
86
What are the major connectors?
These connect components on one side of the arch to components on the other side of the arch:
87
What should you expect in a major connector?
* They should not cover the gingival margins
* They should have as few edges as possible
* Cover as little tissue as they can.
88
What are the two types of major connector?
* A plate connector
* Bar connector
89
Discuss plate connectors
These are used for mucosa support dentures. (therefore not recomended in mandibular as there is not much to provide support)
They cover the gingival margins
90
Discuss bar connectors
These connectors require less mucosal coverage.
They are much thicker to maintain rigidity.
they are used in the mandibular arch as there is less space.
91
Compare a lingual and sublingual bar.
A lingual bar is behind the teeth
A sublingual bar is below the tounge- this is more difficult to place as the floor of your mouth moves when you move the tounge.
92
How do you decide to use a lingual bar or a lingual plate?
There needs to be an 8mm space from the floor of the mouth to the gingival margin for a bar.
If you don't have the space, a lingual plate is used instead.
93
Discuss the advantages and disadvantages of the anterior/ posterior bar.
**Advantages**:
little gingival coverage
rigid connector
relief of the gingival margins (prevents food impaction)
**Disadvantages**:
The many edges may be uncomfortable
As diameter is thinner, there will be thicker cross sectional metal.
Posterior bar provides less support to the free end saddle.
94
Discuss the advantages and disadvantages of a full palatal coverage.
**Advantages**:
rigid connector
Wide relief of the gingival margins
Support across the hard palate for the free end saddle
Less edges
Thinner cross section
**Disadvantages**:
Mucosa is covered so there is no natural sensation.
95
What is the function of major connectors?
* To provide indirect retention
* To assist stability through resisting functional forces in a horizontal direction.
*
96
What is beading?
When you carve into the impression 3mm away from the gingival margin in order to produce an intimate contact between the denture and the tissue.
This prevents food ingression.
97
Compare open and closed saddle designs.
The open saddle design has no gingival coverage. This allows clearance and saliva to go through. It also reduces irritation of the gingival tissues. e.g. minor connectors connected to the saddle.
The closed saddle design has more contact. It provides greater retention but increases irritation to gingival tissues. e.g. minor connectors that also attach to the cingulum of the tooth.
98
Name this denture design:
Mid palatal strap
99
Name this denture design:
Full coverage plate.
100
Name this denture design
Anterior bar
101
Name this denture design
Horseshoe
102
Name this denture
Posterior bar
103
Name this denture type
Anterior posterior bar.
104
What type of denture is this?
A lingual bar
105
What type of denture is this?
A lingual plate
106
what type of denture is this?
a dental bar
107
What type of denture is this?
A sublingual bar.
108
Why should retention be close to the saddle area?
As the saddle area is the location of the dislodging force.
109
Discuss the location of indirect retention in relation to the clasp.
The indirect retention should be seperated from the clasp by the clasp axis.
Without this separation. It is not retentive.
110
What is an undercut?
The area under the maximum bulbosity of the tooth
111
Compare the different types of undercuts.
Soft tissue undercuts- The contour of the alveolar ridge that would prevent the vertical placement of a denture. These can also cause the base to get caught-making removal more difficult.
Hard tissue undercuts- The portion of a tooth surface between the gingival margin and maximum bulbosity where you can place a clasp.
112
How do we identify undercuts?
By surveying the teeth- where you use a graphite marker to draw lines on the teeth.
You try and get the point of the graphite marker into the gingival crevice. If there is an undercut this is not possible.
The undercut is measured as the space between the two lines.
113
Why do we alter the path of insertion?
To get rid of the undercuts
114
What is blocking out and why do we do it?
blocking out is putting wax in the undercuts (where we place the connectors and clasps would go)
We do this so that the RPD doesn't gointo places it shouldn't be (i.e. the undercuts)
115
What is the function of Pin and Post dams?
Compare them
These are ridges which improve the adhesion of the denture.
Pin dam- A shallower groove on the anterior 5mm away from the gingival margin to prevent food slipping under the denture.
Post dam- A ledge on the posterior of the upper denture in the palatal surface.
116
How do we prepare the mouth before we give the patient their new denture
* Deal with the original denture if the patient has it
* Solve problems the patient has
* Periodontal treatment
* Orthodontic treatment
* Fixed prosthetic treatment and endodontics
117
How can we treat patients that have a problem with an existing denture?
* Give them a temporary denture (has less bacteria so gives the gum a break)
* Repair or add to the existing denture
* Use a medicated lining to reduce the inflamation
* Adjust the patients occlusion- by adding GI so the patient's teeth occlude correctly.
* Treat the patient on denture stomatitis ( and educate them that you need to take out your denture at night to prevent this. )
118
What periodontal treatment do we provide for patient's waiting for a new denture?
We need to know the patient's periodontal health and if the patient is motivated to clean the device. Their periodontal status dictates treatment
119
Why could we use orthodontic treatment on patient's wanting a denture?
As the orthodontic treatment could improve the space in the patients mouth or the alignment of the patient's abutment teeth
120
When do we do fixed prosthetic treatments in denture patients and why?
We do them after we have designed the denture but before we make the denture.
This is so we can use the fixed prosthetics to aid the denture such as adding parallel guide planes or rest seats to a crown.
121
When do you prepare the tooth?
Before we create the master casts.
122
How do you prepare rest seats?
Compare Anterior rest seats to posterior rest seats.
Using a slow speed handpeice and cutting into enamel.
Anterior rest seats are cut into the cingulum. Upper rest seats are easier to complete than lowers as uppers have a well defined cingulum.
Posterior rest seats are cut into the marginal ridge.
They should be saucer shape
They have to be deep enough to take a 1mm rest plate.
123
How do you prepare guide planes?
You can only cut 0.5mm of enamel.
But a guide plane should extend 3mm vertically.
124
What are unfavourable surveylines and why are they unfavourable?
Surveylines which are too high.
These are unfavourable as they result in the clasp being placed too close to the occlusal surface which could cause an occlusal interference.
125
How do we prepare the tooth to improve unfavourable surveylines?
We add composite to shape the tooth and produce a lower survey line.
126
Label A
Labial frenum
127
Label A
The buccal suclus
128
Label A
The Rugae area
129
Label A
Hamular notch
130
Label A
Palatine fovea
131
Label A
The vibrating line
132
Label A
Maxillary tuberosity
133
Label A
The Palatine raphe
134
Label A
The labial sulcus
135
Label A
The incisive papilla.
136
What is the hamular notch used for in a denture?
This is the ideal site of the distal border of the denture- This helps with the posterior seal.
137
Label A
The retromolar pad
138
Label A
The Mylohyoid ridge.
139
Label A
The lingual sulcus.
140
Label A
The lingual frenulum.
141
Label A
This is the buccal shelf.
142
What is the relevance of the retromolar pad for complete dentures?
This is a triangular soft pad of tissue used to provide support.
143
What is the retromylohyoid space?
The area at the distal end of the lingual sulcus posterior to the mylohyoid space.
144
What is the Cawood and howell classification used for ?
This is used to classify the type of ridge.
145
What is the ideal ridge classification for our denture patients?
Broad alveolar process.
146
What is the disadvantage of a knife edge ridge classification?
This is painful for the patient because the load goes on the knife edge.
147
How does resorption affect the alveolar ridge.
Upper width decreases.
Lower width widens.
Anterio-posterio - upper resorbs backwards .
Anterior-posterior lower resorbs more vertically.
148
Compare Support, Stability and Retention.
Support- Resistance to vertical movement towards the tissue
Stability- Resistance to horizontal movement
Retention- Resistance to displacement in a vertical direction .
149
What areas in the maxilla provide support for complete dentures?
Hard palate and residual ridge. (the alveolar ridge after bone resorption)
150
What areas in the mandible provide support for complete dentures.
Retromolar pad
Buccal shelf
Residual ridge.
151
How do we achieve a border seal for the denture?
Extension of the denture flanges & incorporation of the post dam.
152
How do you test the retention of a complete denture?
By pulling the anterior teeth away from the tissue.
153
How do we test the stability?
Placing your fingers on the occlusal surface and trying to rock the denture from side to side.
154
Why is a lower denture with dentate uppers unsatisfactory?
Due to the reduced retention of the lowers and the increased load from the upper natural teeth.
155
What is the stage on a prescription card?
This is what you want the technician to do and what you want back
156
What is the date on the prescription card?
This is when you want the work done for.
157
What determines the spacing in the special trays?
Depends on the material used for the master impression.
Alginate
3mm.
Silicone/polyether
upper 2mm.
Lower 0.5-1mm
158
What is border moulding?
This is adding a material to the outside periphery of the trays to fill the functional sulcus e.g. greenstick/ silicone/ wax
159
What are stops?
Used to ensure we have the correct thickness of impression material.
160
Using what material can we make stops and compare the thickness of of stops for each impression mateiral ?
We use greenstick
Silicone- 1mm thick stops
Alginate- 3mm thick stops.
161
Where are stops located in the upper tray ?
In the canine and post dam regions.
162
Where are stops located in the lower tray?
Retromolar pad and the canine area of the ridge.
163
What can we use greenstick for and why?
* To border mould
* To temporarily modify the pt's old denture to check that the modifications that we want to make will improve the denture (make it fit better)
164
When you try in the upper record block during the registration visit it doesn't stay in place- What could be causing this?
If there is overextension of the peripheries
If there is too much lip support.
165
How do we adjust the upper record block?
Lip support-Is nasolabial angle 90degrees & mark the lip line
Incisal level- Is there enough tooth showing ? Add more wax or mark incisal edge
Midline- mark centre line
Buccal corridor- mark canine line using floss from inner corner of eye.
Occlusal plane- using foxes bite plane
-Check occlusal plane & interpapillary line are parallel
-Check occlusal plane and alatragal line are parallel.
LIMBO
166
Why do we mark the lip line?
So that we know how much of the tooth is shown in order to choose the correct height of teeth for the denture.
167
Where should the anterior teeth be positioned?
8-10mm anterior to the incisive papilla
168
What is the incisal plane and what should it be?
This is the level of the incisal edge.
This should be parallel with the interpupillary line.
169
Where does the buccal corridor start?
At the mid-canine line
To find the mid-canine line- Take floss from the inner corner of the eye and drop it down to the nose and then the canine.
170
Discuss the link between dental arch and buccal corridor.
The broader the dental arch, the smaller the buccal corridor.
The narrower the dental arch, the more obvious the buccal corridor.
171
How do we measure the occlusal plane?
Using fox's biteplane and a wooden spatula.
172
What is the neutral zone and discuss it's importance.
Neutral zone- the area with minimum force acting on the tooth.
The denture will be loose if the teeth are not positioned in this neutral zone.
173
What is the ideal denture width and why?
The base of the denture should be wider than the top
This means that the tongue can help push the denture down into position.
174
How do we measure the vertical dimension?
We can use:
Dividers- and select two points in the midline of the face (sites of minimal influence from the muscles of facial expression)
Willis bite gauge- Fixed metal arm should be placed under the nose. The flexible arm should rest below the chin.
175
Compare the RVD and the OVD
How do we position the patient in these.
How does a previous denture affect the positioning?
RVD- the vertical dimension at rest
OVD- the vertical dimension in occlusion.
RVD- get the patient to lick their lips and say m.
OVD- get the patient to place their tounge at the roof of their mouth and bite together. (RCP)
If they have a previous denture- they should wear the upper for RVD measurement and wear both the upper and lower for OVD measurement.
176
What is the freeway space?
The RVD-OVD.
177
What size is the freeway space normally and what can cause an increase in the freeway space?
Normally 2-4mm.
Tooth wear can increase the freeway space
178
What is this and what do we use it for?
The alma gauge.
Used to determine the vertical and horizontal position of the anterior teeth relative to a point in the denture base (incisive papilla)
179
What is the data transfer line A-A on the cast?
The centre line.
180
What is the data transfer line B-B on the cast?
The central incisor plane.
181
What is the data transfer line C-C on the cast ?
This is the residual alveolar ridge contour.
182
What is the data transfer line D on the cast?
This is the canine line.
183
Why do we limit the time the denture sits in the mouth during the try in stage?
Because we are using a denture made of wax- which can melt if left in the mouth for too long.
184
How do we know if the denture is overextended?
It will drop if you move the lips or manipulate the tissues around the denture.
This is because it requires too much lip support.
185
How do we know if the denture is underextended?
It will drop if you hold the tissues away from the denture.
186
How does a high occlusal plane impact the denture?
The tongue will be cramped, making the denture unstable.
187
Describe the contacts of a complete denture?
There should be working side and non-working side contacts.
\*We are aiming for the same as a normal occlusion\*
188
What do the clicking noises mean when the patient is trying in the wax denture?
There is tooth contact- which is caused by too high an OVD creating too small a freeway space?
189
During the try in stage, you have asked the patient to make an sss sound and you hear whistling. What does this mean?
The OVD is too small.
190
What is the Post Dam?
A lip on the back of the denture used to provide a better peripheral seal.
191
Why is it beneficial to cut a double post dam?
This means you will still get a good seal even if you need to reduce the denture size.
192
Label A, B and C.
A-Fit or impression surface.
B- Polishing surface
C-occlusal surface.
193
How can we adjust occlusal interferences?
We can use selective grinding where you adjust the contacting surfaces using articulating paper
\*
Remember contacts= BULL (BUCCAL upper and LINGUAL lower)
or we can re-measure the occlusion.
194
What is the difference between a wax rim and a record block?
Wax rims and record blocks are the same thing.
195
How do you test a patient's neuromuscular control?
Put your finger in their mouth and ask the patient to bite down.
Look at the movement of the tongue.
The posterior part should elevate to hold the upper teeth in place.
The lateral border of the tongue should try and prevent the lower denture slipping.
196
Summarise the visits for a complete denture patient
1. Assessment
2. Impressions
3. Master impressions.
4. adjustment of Record block
5. Tooth trial
6. delivery
197
What are we looking for when checking the occlusal plane?
The occlusal plane and interpapillary line are parallel.
The occlusal plane and ala tragal line are parallel.
198
Compare the two types of compound.
Red compound is used for saddle areas when taking primary impressions.
Greenstick compound is used for border moulding and adjustments at the retromolar area.
199
What is a soft lining material?
How does it work?
Why do we need it?
This is material applied to the inner surface of the denture which has similar features to the mucosa.
It absorbs energy by deformation to reduce the energy absorbed by the surrounding tissues.
Alveolar bone loss results in a reduction of the mucosal thickness. This Diminishes the shock absorption effect.
200
What is a tissue conditioner?
A short term soft lining material e.g. Coe Comfort/ Visco-Gel.
201
How do we adjust the record block for OVD?
Insert the upper and lower record blocks.
Check that the heels are not in contact in the mouth.
Reduce the lower wax rim in height until we achieve the planned OVD with an even contacts with the upper rim
202
Describe what happens in the registration visit?
203
Why do we have surgery pre-prosthetics?
Hard or soft tissues in the mouth can affect the fit of a denture so we surgically remove them.
204
What is a frenectomy ?
Removal of the frenum
205
What is a frenoplasty?
Modification of the frenum
206
What is papillary hyperplasia?
Overgrown soft tissue on the palate which is commonly related to candida infections or a poorly fitted denture.
207
Descibe the clinical presentation in this picture
Flabby ridges- the soft tissue on the ridge interferes with denture retention.
Can happen with combination syndrome.
208
Describe the clinical presentation in this picture
Denture induced hyperplasia-
Check if the ulcer goes away if denture is removed.
Commonly happens if patient wears a temporary denture long term.
209
What is a vestibuloplasty?
Deeping of the sulcus by exposing the periosteum to achieve ridge extension
210
What is an alveoplasty?
Modification of the alveolar process.
211
What is the problem with a knife edge alveolar process and how do we treat it?
Denture will push soft tissues onto it causing pain.
We expose the bone and smooth ridge with a bone file.
212
what is this?
Torus (a bony promienence)
213
Compare tori and exostoses?
Tori are found where there is already bone,
Exostoses are found somewhere that there is not normally a bony promience.
214
When would we need to reduce the genial tubercule or mylohyoid ridge?
If there is severe bone resorption causing the promiences to come to the surface and rub with the denture causing pain.
215
Why would we alter the frenum labially?
It can affect oral hygeine
216
Why would we avoid altering the frenum buccally
Risk of damage to the nearby mental nerve.
217
List some ways in whcih we can secure a denture using implants.
Locator abutments-A button present on the implant & locator inserts are placed in the denture.
This allows the denture to clip into place
Ball abutments-Acts like a ball in socket to secure the denture into place.
Bar & clips (Implants joined together by a soldered gold or titanium bar. The denture has gold/ titanium clips)
218
Discuss the effect of a complete upper denture against natural lower teeth.
* * **Trauma**
(Mucous membrane damage which presents as ulceration and discomfort. Long term trauma causes alveolar resorption and fibrous tissue replacement. We get a fibrous or flabby ridge (Displaceable with not much bone underneath) This is Poor for retention or support causing tipping of the prosthesis.
***Denture instability**- A balanced occlusion is prevented by additional forces and unevenness of teeth. This causes loss of stability in functional movements
219
How do we improve our dentures to deal with Combination syndrome?
* **Reduce trauma to the maxillary denture bearing area** (o Maximise coverage of the denture bearing area by the prosthesis (palatal coverage of hard palate is used to protect the alveolar ridge & Ensure prosthesis covers the primary load bearing sites)
* **Optimise loading of the denture bearing area**- using overdenture abutments (giving an element of toothborne support to the upper denture & reduce the risk of absorption. )
* * **Improve the stability of the maxillary denture**
(Achieving an optimum border seal/Effective post dam/ Deal with the absence of mandibular posterior teeth/ Manage the incisor overbite)
220
How do absent mandibular posterior teeth affect a denture & how do we treat this? ?
All the force is from the anterior teeth & is applied to the front of the denture. This causes the back of the denture to drop down. The force also caused the real anterior teeth to tip forward.
Treatment- A lower partial denture to give a more even occlusal plane, denture stability and stop the tilting.
221
How can an incisor overbite affect the denture fitting?
How do we treat this?
A large overbite means when the maxilla moves forward, the lower anterior teeth can dislodge the upper denture.
Treatment- (affects the aesthetic)
Reduce the incisal edge of the natural teeth.
Sit the denture teeth further up in the mouth- but sitting them higher means you will see less teeth.
222
How does an irregular occlusal plane influence your denture?
An irregular occlusal plane (e.g., over erupted, or missing teeth) requires an irregular denture to fit with the lower dentition. But this is not stabe for the movements of the mandible. The uneven occlusal plane also means there are points of contact that can cause the denture to destabilize (and tilt) in eccentric movements of the mandible.
Treatment:
**Accept**- No adjustments
**Deal with the contact points**: (Minimal localised occlusal grinding /Radical occlusal adjustment)
**Extraction of teeth**- e.g., where tooth is really tilted- making a stable occlusion unachievable
**Overlay appliance**- used in wear cases- an overlay over natural teeth to even out the occlusal plane.
