removable pros Flashcards by em doz

Which of the following materials is most suitable for modifying a stock tray for a primary impression?

a. green stick
b. pink stick
c. silicone putty
d. ribbon wax

c - silicone putty

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What can be defined as the resistance to vertical movement of a denture away from the underlying mucosa

a. stability
b. retention
c. support
d. rigidity

B - retention

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According to Cawood and Howell’s descriptive classification, a class IV ridge is:

a. negative
b. atrophic
c. recent extraction
d. knife-edged

D - knife edged

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Provil putty is a type of what:

a. polysulphide
b. condensation cured-silicone
c. polyether
d. addition cured silicone

D - addition cured silicone

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Which of the following can be defined as:
the difference between the resting face height and the occlusal vertical dimension?

a. interproximal space
b. vertical overlap
c. stability
d. freeway space

D - freeway space

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Which impression material has a double decomposition reaction involving calcium sulphate and is popular because it is cheap and can be used in a stock tray?

a. condensation cured silicone
b. polyether
c. polysulphide
d. zinc oxide eugenol impression paste
e. irreversible hydrocolloid (alginate)

E - irreversible hydrocolloid

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Which impression material is available in sheet or disc form and is softened in a water bath set to 55-60º to be used in stock trays for edentulous ridges?

a. irreversible hydrocolloid (alginate)
b. reversible hydrocolloid (agar)
c. zinc oxide eugenol impression paste
d. impression compound
e. silicone putty

D - impression compound

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Overjet is defined as:

a. a horizontal measure
b. a vertical measure

A - horizontal measure b

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How many times greater does ridge resorption occur in the mandible compared to the maxilla?

4 x

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Define retention -

Resistance to displacive forces directed away from the tissues.

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Define support -

resistance to forces directed towards the hard / soft tissues.

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Define reciprocation -

the compensating element to counteract horizontal force from active clasps.

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Define bracing -

resistance to horizontal forces when fully seated.

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Define what a connector is -

links all the components of the denture together in a place that won’t damage the soft tissues.

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Define indirect retention -

resistance to displacive forces along the retentive axis.

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Define syneresis -

evaporation from the colloid compound, causing the alginate to shrink due to loss of water.

(prevented by wrapping the imp in damp gauze)

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Define inbibition -

when a hydrocolloid compound absorbs too much water, leading to swelling.

(happens when imp is stored for too long in moist environment)

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Define vibrating line -

The junction between the hard and soft palate.

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What is the purpose of having tissue stops on special trays?

Ensures uniform thickness of impression material - can’t press the tray any further.

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What should be written in the lab prescription when requesting an upper special tray for alginate?

please cast impressions in dental stone and construct:

upper special tray for alginate (2-3mm spacing) with tissue stops and stepped handle.

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What should be written in the lab prescription when requesting a lower special tray for PVS?

please cast impressions in dental stone and construct:

lower special tray for PVS (1.5-2mm spacing) with tissue stops, sub-handle and finger rests (x2 in the premolar region).

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What is the recommended spacing for alginate?

2-3mm

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What is the recommended spacing for PVS?

1.5-2mm

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Which is the only reproducible position in edentulous patients?

Retruded Contact Position (RCP)

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Describe Retruded Contact Position

Tooth contact maintained with with jaw moved back around 1mm until the condyles can’t go any further.

Which positioning is not present in edentulous patients?

Intercuspal Position (ICP)

Describe Intercuspal Position

The vertical and horizontal position of the mandible when the upper and lower teeth are in maximum intercuspation (biting).

Describe Occlusal Vertical Dimension

The distance between 2 points (tip of nose and bottom of chin) when teeth are in occlusion.

How is OVD measured?

With a Willis Bite Gauge

How is freeway space calculated?

RFH - OVD = FWS

What does Foxes Occlusal Plane Guide measure?

The occlusal plane parallel to the alar tragal line.

What does the Alma gauge measure?

The incisal edge relationship to the incisive papilla in a horizontal and vertical measure (8-10mm)

Curve of Spee

anterior-posterior curve from the cusp tip of the mandibular canine along the cusps of rest of posterior teeth.

Curve of Monson

bilateral curve through the buccal and lingual cusps of mandibular molars going through the tongue.

Are radiographs justified in the treatment planning stage of complete denture provision?

**No** - unless there is a clear indication (e.g: suspected retained roots).

Which pathogen is associated with denture stomatitis?

candida albicans

Which condition may occur concurrently with denture stomatitis? (also fungal)

angular chelitis

What is the minimum inter-occlusal clearance in the premolar region? (FWS)

2-4 mm

Example of a **chairside** soft reline material:

Coe-soft

Example of a tissue conditioner:

visco-gel

Example of a definitive soft-lining material:

molloplast-B (silicone based)

Example of a definitive **soft** reline material:

self or heat cured acrylic resin

When is a primary jaw reg indicated?

For **cobalt-chrome** - design is influenced by occlusal relationships.

When is a primary jaw reg **not** indicated?

1. when a complete denture is going to oppose the partial 2. acrylic dentures only

How deep should rests be prepared into enamel?

0.5-1mm

Which stage follows second impressions when creating a cobalt chrome denture?

framework try-in

Outline the clinical stages when making **complete dentures**.

1. Treatment planning, diagnosis and 1st imps 2. 2nd imps 3. Jaw Reg 4. Try In 5. Fit

Problems arising from **insufficient FWS**:

(teeth too big) - pain beneath dentures - MoM and TMJ pain - difficulty chewing and speaking - difficulty making an oral seal with lips

Problems caused by **excessive FWS**:

- poor appearance (over-closed) - difficulty chewing - TMJ discomfort - cheek biting

Which 3/4 components provide support?

1. rests 2. saddles 3. connectors and collets

Which components provide retention?

1. clasp length 2. guide planes 3. ridge undercut in saddle areas

Which components provide reciprocation?

1. collets 2. passive arms opposing clasps 3. rests

Which components provide bracing?

1. collets 2. passive arms opposing clasps 3. rests 4. clasps 5. flange extension in saddle areas 6. connectors on vertical surfaces 7. guide planes

How many mm of depth does a lingual bar need?

8mm

How much of a clasp needs to be in undercut?

the final 1/3

Sizes of Undercut:

**0.25mm** - Co/Cr **0.5mm** - stainless steel **0.75mm** - gold

Preston’s Golden Nugget

You can have a rest without a clasp but you can’t have a clasp without a rest.

What do you need for stable occlusion?

tripodisation of 3 index teeth

What is the path of insertion for when an anterior saddle is present?

anterior to posterior

Path of insertion for when no anterior saddle is present.

posterior to anterior

What type of acrylic is used for over denture bases and why?

polyethereytherketone (PEEK) - used due to excellent chemical resistance.

Which type of lower CoCr connector provides maximum indirect retention?

lingual plate

When picking a mould of denture teeth, the theory of the shape of a tooth resembling the face shape can be used. **What is the name of this theory?**

Leon-Williams face form - (think of it as mr bassi - mrs williams collab)

Which piece of equipment is used to measure lip support and what should the ideal reading be?

**alma gauge** - 9-12mm (measures incisal edge position in both a horizontal and vertical plane relative to the incisal papilla)

What material is applied to the upper and lower reg rims to record centric occlusion?

aquasil

When would a reg be required for immediate dentures?

no stable occlusion

What is the one surface that cannot be changed for a copy denture?

the polished surface

In what situation would a jaw reg be appropriate when constructing a copy denture?

when a change in OVD is planned

Classes of ridge assessment:

1 - dentate 2 - immediately post XLA 3 - well formed ridge 4 - knife edged ridge 5 - flat ridge 6 - negative ridge

What is the name for the distance between upper and lower incisors in the horizontal plane and what is its average value?

overjet (forward), 2-4mm

The distance between upper and lower incisors when viewed anteriorly.

overbite

**Saddle** -

The part of the denture which covers the edentulous area containing toothwork etc.

**Connector** -

Joins together the components of a denture. (e.g: plate, ring, lingual bar / sub-lingual bar)

**Retention** -

Resistance to displacive forces **AWAY** from the tissues. (clasps, guide planes, ridge undercut in saddles)

**Support** -

Resistance to displacive forces directed **TOWARDS** the tissues. (rests, saddles, connectors and collets)

**Reciprocation** -

The compensating element to counteract the **horizontal forces** from an active clasp. (collets, passive arms, rests)

**Bracing** -

Resistance to horizontal forces **when fully seated**. (collets, passive arms, rests, clasps, flange, connector, guide planes)

**Indirect Retention** -

Resistance to displacive forces **along the retentive axis** — this is through the tips of clasps. (rests, connectors, collets, guide plates)

**Guide Planes** -

two or more parallel surfaces on abutment teeth used to limit the path of insertion and provide retention/stability.

**Free End Saddle** -

An edentulous area posterior to the natural teeth.

**Kennedy Class I** -

bilateral free end saddle.

**Kennedy Class II** -

Unilateral free-end saddle.

**Kennedy Class III** -

Unilateral bounded saddle.

**Kennedy Class IV** -

anterior bounded saddle only - **no modifications**!

When can a lingual bar be used?

When there is around 8mm between the floor of the mouth and the gingival margin to give 3mm clearance from the gingivae.

What are the 2 purposes of **rests**?

To provide **support** and **prevent overeruption**.

How do clasps provide retention?

By engaging the undercut of the tooth.

Which type of clasp can be used when there is a **high survey line** present?

ring clasp

Which clasp can be used when a **diagonal survey line** is present sloping downwards?

gingivally approaching clasp

What should be done when a **low survey line** is present?

Modify the tooth with composite.

Which type of clasp can be used when a **medium survey line** is present?

C clasp

What is the name of the powder mixed with water to form study models in dental stone?

gypsum (made from calcium sulphate)

Term for when alginate absorbs water:

imbibition

Term for when alginate loses water and shrinks:

syneresis

If a denture is mucosal bourne, where should the flanges extend to?

depth of the functional sulcus

what is the benefit of using a wrought gold clasp?

it has a high modulus of elasticity

minimum length of co-cr clasp

14mm

minimum length of stainless steel clasp

7mm

minimum length of wrought gold clasp

5-6mm

which type of lower co-cr connector provides maximum indirect retention.

lingual plate

How much space is required for a lingual bar to be provided?

3mm between bar and gingival margins, 1mm space between lingual sulcus.

How far should special trays extend into the gingival sulcus?

2mm short of full sulcus depth

Where should the rest seat be placed for a posterior free end saddle?

mesially - full collet required to reciprocate.

What are special trays made from?

Visible-light-cured acrylic (VLA)

Green stick is a type of which thermoplastic impression material?

impression compound

Spacing for alginate and addition cured silicone?

alginate - 3mm silicone - 1.5-2mm

Pt complains of pain from lower ridge area during swallowing, PIP is applied. **Where would you expect to see pressure and what causes it?**

Seen on the mylohyoid ridge - caused by overextended flange due to overextension of impression trays.

When would a reg be required for immediate dentures?

In a pt with unstable occlusion.

Pt with C/C presents with pain that worsens throughout the day. OE, you notice tenderness of MoM - **what issue the cause of these issues?**

Insufficient FWS

Denture pt presents with burning sensation over DBA, constantly present. **How would you manage this?**

referral to oral med

What is the cause of dentures lifting / tilting?

uneven contacts

Pt complains of whistling sounds when they say ‘S’. **What is the most likely denture fault?**

Teeth set too far back so not enough room for tongue.

Pt complains of a lisp when they talk. **What is the most likely denture fault?**

Teeth set too far forwards so too much room for tongue.

visco-gel and coe-comfort are examples of what?

tissue conditioner

What is the only indirect relining technique where the denture is sent to the lab?

heat-cured (hard reline)

What is the management of a pt who complains of pain on abutment teeth?

Increase FWS (overopened)

Management of pts complaining of denture tilting and displacement during eating?

caused by uneven occlusal contacts - follow the BULL rule (non-working)

Which type of acrylic is used to repair a fractured denture?

cold cure acrylic