Impression Materials

Question 1

How materials interact with its enviroment & pateitns, properties, contex of use.

Answer 1

Biocompatibility

fundamental requirement for any dental restoration.

Question 2

The breakdown of mateirals int he oral enviroment

Answer 2

Biodegredation

Question 3

What are somethigns we look for when choosing dental materials?

Answer 3

• Long term testing & trials
• Internationall reconized spec & standards
• Maximun saftey, durable, effective
• Lower risk due to low knowledge

Question 4

Whos responsibility is it toweigh the quality of evidence regarding manufacturers’ claims from an informed, intelligent perspective to ensure optimum treatment outcomes for the patients.

Answer 4

The dentist

Question 5

Dentists are expected to acquire sufficient knowledge of the what 3 things?

of dental materials used in the rehabilitation of the edentulous patient.

Answer 5

1. Properties
2. Behavior
3. Limitations
   Of all mateirals

Question 6

What is the goal of optimal impressions?

Answer 6

1. Retention
2. Support
3. Stability
   of denture!

Question 7

Impression for complete dentures must what?

Answer 7

be capable of capturing and replicating all anatomical peripheral and denture-supporting structures

Question 8

Just look lol

Answer 8

Just look

Question 9

an imprint produced by ‘the pressure of one thing upon or into the surface of another

Answer 9

Impression

Active + making

Question 9

an impression made for the purpose of diagnosis or for the construction of a custom tray.

Answer 9

Preliminary Impression

Question 10

What mateirals do you need for a preliminary impression?

Answer 10

1. Stock tray
2. Alginate

Question 11

An imprint that record the entire functional denture-bearing area to ensure maximum support, retention and stability for the denture during use.

Answer 11

Final Impression

Question 12

What is the purpose of a final impression?

Answer 12

To record accurately the tissues of the denture bearing areas, in addition to recording the functional width and depth of the sulci.

Anatomy of mouth!

Question 13

What are the 3 diffrent impression techniques?

Answer 13

1. Mucostatic
2. Mucocompressive
3. Selective Pressure

Question 14

impression is made with the mucosa in its normal resting position.
* lead to good fitting denture
* During chewing denture will pivot on incompressbale areas and dig into compressible areas

Answer 14

Mucostatic impression

Question 15

**The impression is made when the mucosa is subject to compression. **
* Denture is most stable during function not at rest
* Hard tissue not compressed

Answer 15

Mucocompressive impression

What we do

Question 16

The impression is made with stress bearing areas being compressed and stress relief areas being relieved.

Answer 16

Selective pressure impression

Question 17

What are the 2 main categories of impression materials?

Answer 17

1. Ridgid
2. Elastics

Question 18

What kind of impression mateiral?

impression plaster, zinc oxide eugenol paste, and dental impression compound

Answer 18

Ridgid/ non-elastic

Question 19

What rigid material is used from boarder molding of custom trays?

Answer 19

Compound

Question 20

What are 2 reasons why ridgid impression materials are bad?

Answer 20

1. Inability to withdraw from undercuts= fracture easily
2. No elastic defromation, does not recover past set
   3.

Question 20

What impression mateiral?

used as a mucostatic impression material for making final impressions for edentulous patients
* does not compress or displace tissues
* not used often

Answer 20

Impression plaster

Question 21

What impression mateiral?

• Rigid
• May fracture in the presence of undercuts.
• Set material does not adhere to set plaster or stone.
• Power, liquid, or paste
• < 0.1% setting shrinkage= impression stored for long time with **no distortion **

Answer 21

Zinc Oxide Eugenol (ZOE) Impression Paste

maining used fro final impression of endentulous ridge

Question 22

What impression mateiral can be used as a surgical dressing and why?

Answer 22

Zine Oxide Eugenol paste because it is soothing + anti-inflammatory

Question 23

What are 4 adavantages of ZOE

Answer 23

1. Dimensional stability 2. Good surface detail 3. Can be added on to exsisting ZOE 4. Mucostatic or mucocompressive

Question 24

What are 4 Disadvantages of ZOE

Answer 24

1. Can be used with deep undercuts 2. sets quickly if thin 3. Eugenol allergies 4. Stining + burning

Question 25

# What impression material? * Rigid * Modeling plastic * Thermoplastic; heat to mold * cakes or sticks, with the colors representing different fusing temperatures.

Answer 25

Dental Impression Compounds | green sticks for us

Question 26

**Dental compound** is a **mixture of waxes and thermoplastic resins plus fillers** that increase ____ above mouth temperatures and provide ____ at room temperature.

Answer 26

Above mouth temp= viscosity (heat at 124F by flame or water bath At room temp= rigidity

Question 27

WHat type of dental impression compound do we use in lab?

Answer 27

Type 1 lower fusing material for boarder molding | can also be used for pre-liminary impressions

Question 28

What two was can impression compound be heated?

Answer 28

1. Direct flame for sticks 2. Waterbath

Question 29

Whar are the two categories of elastic material?

Answer 29

1. Synthetic elastomer 2. Hydrocolloids

Question 30

# What material? considered one of the **most accurate impression materials for recording fine details** because of their low viscosity and great degree of recovery after deformation around undercuts.

Answer 30

Reversible Hydrocolloids; Agar

Question 31

# What impression material **Most widely used impression materials in dentistry:** ease of manipulation, no need for expensive equipment, relatively low cost, and comfort to patients.

Answer 31

Irreverisble Hydrocolloids; Alginate

Question 32

**the setting of a reversible hydrocolloid.** Is a solidification process that involves phase changes from sol to gel states, induced by a change in temperature.

Answer 32

Gelation of Agar | reversible

Question 33

* Long working time (5 min set) * can be poured immediatley * limited use in making fix prosth

Answer 33

Agar; reversible hydrocolloids

Question 34

Whay is the most commonly used category of impression materials today?

Answer 34

Synthetic Elastomers

Question 35

What were the were the first **synthetic elastomeric** material to be introduced in 1950.

Answer 35

Polysulfides | drawback is distorition over time

Question 36

Silicones and polyethers form the majority of what impression mateira used today?

Answer 36

Elastomeric impression mateirals

Question 37

What are 3 steps to making impression with elastomeric materias?

Answer 37

1. custom trays 2-3 mm short of sulcus 2. boarder molded green compoound 3. verify proper seal

Question 38

# What impression material? **two-paste system** that is available in low, medium, and high consistencies and is made up of a **base and accelerator/reactor**.

Answer 38

Polusulfide rubber

Question 39

What occurs when the pasted of polysulfied rubber are mixed together?

Answer 39

Polymerization rxn occurs

Question 40

How do you know polysulfied rubber is set and why? How soon to pour?

Answer 40

paste has tunred to dark brown rubber, due to prescence of lead oxide; **pour within 1 hour** **stinks**

Question 41

Characteristics of polysulfied rubber

Answer 41

* great detail * long working time * good flexibility * high tear strength * hydropphobic so dry tissues prior * mess, smells bad.

Question 42

Polysulfied rubber to record the soft tissues for edentulous patients under ____ _____

Answer 42

minimum compression

Question 43

# What impression mateiral * Highly accurate * High dimensional stability * Multiple casts * Easy to mix * Pleasant odor disadvantage: 1. Expensive 2. sulfur inhibit set; no latex gloves 3. short working time

Answer 43

Polyvinylsiloxanes (PVS/VPS)