Pros Flashcards
What are the components of an RPI? (3)
Rest on mesial surface,
Proximal plate on distal surface,
gingivally approaching I-Bar.
What is the mechanism of action for an RPI (3)
Mesial rest acts as axis of rotation.
During occlusal load
The proximal plate and I-bar rotate downwards and mesially respectively around the axis of rotation
The I-bar and proximal plate disengage from the tooth/undercuts.
Thus, potential traumatic torque is avoided
An 85 year old lady attends your practice for the first time. She is complaining of generalised pain underneath her
lower complete denture on the left side. She is also edentulous in the maxillary arch and successfully wears a
complete upper denture. She gives a history of the denture becoming progressively looser during the last 2 years.
On examination you suspect that the cause of the pain may be related to an unerupted sound second premolar
tooth that is now partially visible.
Describe two common radiographic views used to assess the position of the tooth. (4 marks)
OPT and (mandibular) oblique occlusal
2X PA’s at differing angles to one another
= Parallax: My pal follows me rule or SLOB
An 85 year old lady attends your practice for the first time. She is complaining of generalised pain underneath her
lower complete denture on the left side. She is also edentulous in the maxillary arch and successfully wears a
complete upper denture. She gives a history of the denture becoming progressively looser during the last 2 years.
On examination you suspect that the cause of the pain may be related to an unerupted sound second premolar
tooth that is now partially visible.
Given that, in this patient, the mandibular denture bearing area is very resorbed and the patient has osteoporosis.
What possible complications could arise if extraction of this tooth was attempted? (4 marks)
Regulars: pain, swelling, bruising, infection, dry socket,
Mandibular fracture (atrophic mandible)
MRONJ (bisphosphonates for osteoporosis)
Immunosuppressed & elderly = higher infection risk
Nerve damage since mental foramen closer or if theres a fracture
An 85 year old lady attends your practice for the first time. She is complaining of generalised pain underneath her
lower complete denture on the left side. She is also edentulous in the maxillary arch and successfully wears a
complete upper denture. She gives a history of the denture becoming progressively looser during the last 2 years.
On examination you suspect that the cause of the pain may be related to an unerupted sound second premolar
tooth that is now partially visible.
You decide, after discussion with the oral surgeon, that the tooth should remain in situ. Outline your approach for
the design of a replacement lower denture that would be stable and comfortable in function. (12 marks)
- Check the denture is retentive/ has sufficient support and stability
- Check occlusion.
- In jaw registration stage we are checking the RVD/ OVD/ FWS and neutral zone.
- Get the patient to decide their tooth shade & shape
- Check extension- so that it does not impinge on frenal attachments or the neutral zone .
- Place a relief in the region of the 2nd molar (leaves space for the application of a soft lining material under the area of the premolar)
What measurements are required for a lingual bar?
8mm depth. 4mm height of bar, 3mm from the gingival margin, 1mm from the depth of the functional sulcus of floor
of mouth
3 differences between new and old dentures on image (3)
Increased occlusal Vertical dimension - tooth wear,
Flange extension (and thickness?)
Tooth shade
Name anatomy of the upper and lower jaws.
Define Support retention and stability, indirect retention.
Support- Resistance to occlusally directed loads e.g. rest seats.
Retention: resistance to vertical displacement (can be mechanical e.g. clasp/ musclar e.g. Buccinator/ orb.oris/ Physical e.g. cohesion and adhesion.
Stability: is resistance to horizontal displacement forces in function (keep denture in neutral zone)
Indirect retention: Resistance to rotational displacement forces. It is provided by supporting components e.g. a rest
preventing distovertical rotational displacement of a saddle. Should be ideally 90° to the axis of rotation. Should be
on the opposite side of the axis of rotation to the displacing force. Mainly used in free end saddles.
3 ways upper complete retained (3)
- Mechanical: via clasps, guide planes
- Muscular: via action on muscles on the shape of the polished surface of denture
- Physical: adhesion (Forces of saliva on the denture)
/cohesion (forces within the saliva such as viscosity)
atmospheric pressure
Extension into;
sulcus, vibrating line/post dam region = peripheral seal, hamular notches
What is the Biometric guidance setting upper and lower teeth (5)
Aim to place teeth in their pre extraction sites;
- Maxillary teeth placed buccally to the ridge promotes lower denture stability.
- Mandibular teeth placed over the ridge so the palatal cusps of uppers occlude with fossa of lowers and the forces are appropriately directed.
- Positioning lower teeth over the ridge reduces tongue restriction
What is the aetiology of denture stomatitis? (3)
Poor denture hygiene
dentures worn at night
immunocompromised.
How do we manage denture stomatitis? (7)
Local measures first:
Denture Hygiene Instruction
brush palate daily
clean denture thoroughly - soak in CHX (0.2%)or sodium hypochlorite (acrylic only) for 15 mins 2x per day.
Wear dentures as little as possible
Miconazole oromucosal gel (20mg/g) applied 4 times daily after food.
Fluconazole 50mg (1 tablet for 7 days)
new dentures made when health restored
How do you restore freeway space in very worn dentures?
occlusal pivots-
restore occlusal surface with auto-polymerising acrylic resin (provisional)
A gap between posterior teeth in mandibular protrusion makes the occlusion unstable.
What problem can occur with a complete upper denture occluding with a partial lower? (1)
Combination syndrome
-Natural teeth producing alot of force aginst the edentulous maxillary ridge.
Resulting in a ‘flabby ridge’ due to
- trauma to mucous membrane -> ulceration/chronic discomfort under denture -> bone loss & fibrous tx deposition
* Papillary hyperplasia of the hard palate
* Bone loss from the anterior part of the maxillary ridge.
- Hypertrophy of the tuberosities
- Extrusion of mandibular anteiror teeth
Why does combination Syndrome occur. (3)
Lower natural teeth apply greater forces to the anterior upper denture over a prolonger period of time
Continuous displacement results in excessive and rapid bone loss of anterior alveolar ridge
This is replaced by excess fibrous tissue.
How do we manage combination syndrome? (2)
- how do we achieve this
Treatment:
* New denture covering the whole denture bearing area including priamry load bearing sites with good peripheral seal/post dam (reduces trauma to the denture bearing site)
- AND Opposing arch denture providing posterior support.
Take a mucostatic impression so the tissues are recorded at rest.
Use a 2 stage impression with a medium body first
Then cut out impression material and make hole in tray over flabby ridge and take 2nd impression with light body.
OR
Can use window technique where relief hole is cut in special tray where flabby ridge is to allow flow of impression material and leave tissues undisplaced.
1st imp = use mucocompressive e.g. zinc oxide eugenol
2nd imp = mucostatic imp using a low/medium viscosity impression material in the ridge area
Define Kennedy Class 2 Mod 1
Unilateral free end saddle with 1 bounded saddle.
What is a system of design used for designing partial dentures?
- outline saddle area,
- support,
- retention,
- stability and reciprocation,
- connector - minor and major
- simplify
Give examples of maxillary and mandibular connectors designs
Provide advantages and disadvantages for each.
Maxillary:
midpalatal strap/horsehoe
Adv- Not covering gingivae/full palate.
Disadv- Not as much mucosal support
Full palatal coverage
Adv-provides mucosal support
Disadv- covers the palate (cannot feel hot fod or drinks/
Mandibular:
Lingual plate:
Adv- thinner diameter/ less edges for the tongue to explore.
Disadv-covers the gingival margin
Lingual bar
Adv- Gingival margin is clear
Disadv-Need the 8mm space.
Plate/strap:
Maxillary - midpalatal, horseshoe
Mandible - lingual plate
– thin in cross section but rigid
- fewer edges for tongue to explore
X - mucosal coverage (+/- gingival margin coverage)
Bar:
Maxillary - anterior posterior ring
Mandible - lingual bar
- gingival margin clearance
- less palatal coverage
- lingual bar well tolerated
X- More edges for tongue to explore
X - thicker in cross section to ensure rigid
X - Lingual bar hard to clean
What is an RPI?
Stress relieving clasp system used in free end saddles.– rest seat mesial to saddle area, proximal plate and I-bar.
Rest mesially acts as axis of rotation. As the proximal plate and I-bar rotates downwards and mesially (respectively) around the axis of rotation
during occlusal load. The I-bar and proximal plate disengage from the tooth/undercuts. Thus, potential traumatic torque is avoided
What is Alwood and Howell’s classification of a ridge?
I. Dentate
II. Post extraction (can see the socket)
III. Broad
IV. Knife-edge
V. Flat (no alveolar process)
VI. Submerged (loss of basal bone leading to an inverted ridge)
What is a knife-edge ridge?
Rapid resorption of lingual and buccal alveolar bone with a hard sharp bony presentation with thin gum overlying it
Name 3 reasons for a knife-edge ridge
Immediate dentures, periodontal disease before XLA, traumatic surgery for XLA.
How is a knife-edge ridge managed for a complete denture? (3)
Soft reline on denture fitting surface
Surgical removal of sharp bony spots if painful
If there are specific sore areas (relief can be put on the denture to relieve the pressure there)
What is the difference between a soft lining and a tissue conditioner?
A soft lining may be used to reline a healthy mucosa;
as a cushion/shock absorber
In atrophic/knife-edge ridges.
Those with parafucntional habits
A tissue conditioner is a more immediate and short term option and is used in unhealthy(inflammed)/ulcerated mucosa to aid healing.
It also dissipates forces but is a more short-term option.
What is a functional impression?
An impression taken with a tissue conditioner. The material is applied and the patient wears the denture and impression in function for approx. 24 hours.
They return and the impression is sent to the lab for a reline.
Other than remaking them how can you improve the retention of dentures? (4)
Adjustment of any overextended areas:
Overextension lingually- tongue will move the denture
Overextension buccally- Soft tissues will move it.
(hard?) Reline -
Soft- replacing part of the surface material (e.g. a smaller gap affecting retention)
Hard- improving the post dam region to provide a better peripheral seal)
Rebase - replacing the entire fitting surface (e.g. improving the post dam region for a peripheral seal)
Add clasp
Adhesive
Other ways retention can be improved (remaking them)
Implant retained denture.
Precision attachments (Interlocking piece between the crown and the denture),
How can you check retention clinically? (4)
Partial dentures
Pull vertically on anterior teeth region to see if the denture pulls out of the patients mouth.
Complete denture
Does it drop when we:
* Pull the tissues out the way of the denture
* Tissues are manipulated
* Patient moves their lips.
Lower denture- does it move when patient moves their tongue forward(on lower denture)
‘Pull’ on premolars – push on anteriors to check post dam.
Describe the process of making a replica denture
Consent and explanation.
Stage 1-replica mould of old denture
1. Clean the dentures (modify with greenstick)
2. Replicate the denture using lab putty & stock trays out of the mouth.
Place Adhesive then lab putty on the inner surface of one tray and the outer surface of the other tray.
Seat the denture occlusal surface down on the inner tray putty. Mould the putty to 2mm of the edge of the denture. Place vaseline and locating notches (aid removal)
Place lab putty on the fitting surface of the denture & sit the 2nd tray outer surface down.
- Once set-Remove the dentures from the mould/& disinfect & send to lab. (For replica wax blocks on a shellac base)
Stage 2:
Take master impressions using the replica blocks. (e.g. extrude polyether)
Complete the jaw registration with both record blocks.
Continue as normal dentures from here.
What problems can an incorrect OVD give? (7)
Folded comissures of the mouth due to reduce facial height.
Angular cheilitis (infection of the comissures)
Clicking teeth when eating (Reduced FWS)
Whistling (Increased FWS)
Incompetent lips (increased facial height)
TMD aggravation
Pain in mandibular muscles
occlusal trauma in RPD.
If OVD is excessive
= progressive pain throughout day
= Sore TMJ and MOM
= whistling speech
If OVD insufficient
= lack face height
= deep creasease at commissures
= repeated angular cheilitis
Denture stomatitis- What microbe is involved. Give the 4 virulence factors of this microbe?
Candida albicans.
Altering the target site to prevent azoles binding
Changing the cell membrane composition to prevent the insertion of polyene into the cell membrane.
Hyphae causing damage to host tissue.
Hydrolytic enzymes- attachment to host cells & causes cell structure.
What is your initial treatment plan to treat denture stomatitis?
Local measures:
Brush the palate daily
Clean the dentures (Soak in Chlorohexidine or sodium hypochlorite if acrylic for 15 minutes twice a day)
Leave the dentures out as much as possible during treatment.
Denture care advice:
- Remove denture at night & store it in water.
- Clean with a dry tooth-brushing over a sink of water after each meal and at night,
If patient uses an inhaler advise that they should rinse after inhaler use.
**Denture adjustment **
Ensure the dentures are adjusted (a loose/ ill fitting denture can make the problem worse)
We can use a temporary reline on the fitting surface of the denture to prevent pressure on the infected gingivae until it heals. (e.g. Viscogel)
Drug treatment
If initial OHI & chlorohexidine doesn’t work or patient is immunocompromised.
Good OH patient/ no dry mouth- Topical or systemic antifungal.
Dry mouth patient- topical antifungal (systemic should be avoided)
Immunocompromised- systemic antifungal + topical antifungal.
Topical- Miconazole oromucosal gel (20mg/g) pea sized amount applied after food 4 times daily.
Systemic- Fluconazole 7x 50mg capsules 1 daily.
Nystatin 30ml- used for when patient is on warfarin or statins (Fluconazole and miconazole contraindicated)
Name 5 medicines you could use for a denture stomatitis
Topical:
* Miconazole = 20mg/1g use: pea size 4x daily (after food) for 7 days
* Nystatin = oral suspension 30ml use: 1ml after food 4x daily for 7 days
* Chlorohexidine = 0.2% use 10ml 2x daily
Systemic:
* Fluconazole 50mg capsules use: 1x daily for 7 days
* itraconazole
Patient has denture stomatitis- you decide they need a new denture - What can you do in the short term for the patient’s current denture? (2)
what are the advantages?
Improve denture hygiene
Add a temporary reline e.g. coe-comfort or viscogel.
This:
Allows Inflammation of the denture bearing muocsa to resolve (need to regain normal volume and contour prior to our new impression)
Prevents pressure on the infected oral tissues.
Where should your post dam be?
1-2mm anterior to the palatine fovea extending from hamular notch to hamular notch along the vibrating line.
vibrating line = this is the junction of the hard and soft palate and iscompressible tissue.
What is the distal extension of a lower complete denture?
2/3rd onto retromolar pad.
Why is the buccal shelf used for support?
It is non-resorbable.
What anatomical features help set the incisors? (4)
Incisive papilla (upper anteriors 8-10mm anterior to the incisive papillae)
Alveolar ridge (upper incisors set buccal to and lower incisors should be set on the ridge)
Philtrum of the lip for the midline.
Resting lip line = Have 1-2mm incisal edge showing when the lips are at rest.
What 4 things make up the shade of teeth. ?
Value, chroma, hue and translucency.
Give the average horizontal bone loss for incisors post extraction
Incisors – 6.3mm,
Give the average horizontal bone loss for canines post extraction.
Canines – 8.5mm,
Give the average horizontal bone loss for premolars Post extraction.
10mm,
A 48-year-old male patient presents for the first time in your practise. He is otherwise fit and healthy and takes no medications. He also wears a complete upper denture which is 9 years old.
What is noticable about the patient’s palatal tissue? (2)
Erythematous, Papillary hyperplasia
A 48-year-old male patient presents for the first time in your practise. He is otherwise fit and healthy and takes no medications. He also wears a complete upper denture which is 9 years old.
What diagnosis would you make? (1)
Denture induced stomatitis - erythematous candidiasis
A 48-year-old male patient presents for the first time in your practise. He is otherwise fit and healthy and takes no medications. He also wears a complete upper denture which is 9 years old.
What would be your first line of treatment? (2)
Local measures:
Denture care advice
Brush the palate daily
Clean the dentures (Soak in Chlorohexidine or sodium hypochlorite if acrylic for 15 minutes twice a day)
Leave the dentures out as much as possible during treatment.
Remove denture at night & store it in water.
Clean with a dry tooth-brushing over a sink of water after each meal and at night,
If patinent uses an inhaler advise that they should rinse after inhaler use.
**Denture adjustment **
Ensure the dentures are adjusted (a loose/ ill fitting denture can make the problem worse)
We can use a temporary lining (tissue conditioner) on the fitting surface of the denture to prevent pressure on the infected gingivae until it heals. (e.g. Viscogel)
Drug treatment
If initial OHI & chlorohexidine doesn’t work or patient is immunocompromised.
Good OH patient/ no dry mouth- Topical or systemic antifungal.
Dry mouth patient- topical antifungal (systemic should be avoided)
Immunocompromised- systemic antifungal + topical antifungal.
Topical- Miconazole oromucosal gel (20mg/g) applied after food 4 times daily.
Systemic- Fluconazole 7x 50mg capsules 1 daily.
Nystatin 30ml- used for when patient is on warfarin or statins (Fluconazole and miconazole contraindicated)
A 48-year-old male patient presents for the first time in your practise. He is otherwise fit and healthy and takes no medications. He also wears a complete upper denture which is 9 years old.
If this condition persists after first line of treatment what would be the next line of treatment to pursue?
Appropriate antifungal treatment
* Miconazole = 20mg/1g use: pea size 4x daily (after food) for 7 days
* Nystatin = oral suspension 30ml use: 1ml after food 4x daily for 7 days
Systemic:
* Fluconazole 50mg capsules use: 1x daily for 7 days
A patient recently underwent an extraction of teeth 15 and 16. They arrive 3 months post extraction and request a cobalt chrome partial denture.
- What are the edentulous classifications for maxilla?
Atwood, Caldwell and Howell
I- Dentate
II- Post extraction (the teeth have just been taken out so you can see the socket)
III- Broad alveolar process (the ideal situation for our denture patients)
IV- Knife edge (can be painful for patients because the load goes on the knife edge part.
V- Flat ridge (no alveolar process)
VI- Submerged ridge (loss of basal bone causing an inverted ridge)
A patient recently underwent an extraction of teeth 15 and 16. They arrive 3 months post extraction and request a cobalt chrome partial denture.
The patient has all their other teeth.
Outline a design to replace the 15 and 16.
A patient has the following missing teeth: 38, 37, 36, 35, 45 and 46. You decide to provide a definitive removable partial denture. The patient has a well maintained mouth with no active disease and you can assume has suitable survey lines.
What supporting components would you use? List the type, tooth (FDI) and surface.
2020 Paper1 (q6)
47 mesial occlusal rest
44 Distal Cingulum rest
43 Cingulum rest
34 MESIAL cingulum rest
Would the premolar not be occlusal rest ?
| Need to consider indirect retention aswell
A patient has the following missing teeth: 38, 37, 36, 35, 45 and 46. You decide to provide a definitive removable partial denture. The patient has a well maintained mouth with no active disease and you can assume has suitable survey lines.
2 List the retentive components that you would use. Indicate component name, what tooth (FDI) and position if appropriate. (3 marks)
2020 Paper1 Q6
- 34 gingivally approaching I bar clasp
- 44 gingivally approaching I bar clasp
- 47 self-reciprocating occlusally approaching clasp.
A patient has the following missing teeth: 38, 37, 36, 35, 45 and 46. You decide to provide a definitive removable partial denture. The patient has a well maintained mouth with no active disease and you can assume has suitable survey lines.
Name the major connector(s) and state the reasons for your choice including the choice of material. (3 marks)
2020 Paper1 Q6
Lingual bar
- Cover less of the mucosa
- Rigid
- Wide relief of gingival margins = easier to clean and prevent food impaction
- well tolerated
Material- Cobalt chromium.
A patient has the following missing teeth: 38, 37, 36, 35, 45 and 46. You decide to provide a definitive removable partial denture. The patient has a well maintained mouth with no active disease and you can assume has suitable survey lines.
Which feature of your design would provide indirect retention?
2020 Paper1 Q6
43 cingulum rest.
The illustration above is of an upper edentulous ridge. Please identify the anatomical landmarks indicated. (3 marks)
2020 PAPER 1 Q7
A- incisive papilla
B- Maxillary tuberosity
C-palatine fovea
