Phillips Dental Material Impression Materials Flashcards

1
Q

According to Phillips Dental Materials: What is agar/reversible hydrocolloid?

A

An aqueous impression material used for recording maximum detail

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2
Q

According to Phillips Dental Materials: What is alginatre/irriverasable hydrocolloid?

A

An aqueous impreesion material used for recording minimal detail

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3
Q

According to Phillips Dental Materials: What are characteristics of ZOE impression paste?

A

Cannot be removed past undercuts without distortion Impressions become rigid Inelastic Do not compress the tissue during seating Hard tissue structures of the mouth

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4
Q

According to Phillips Dental Materials: What are characteristics of elastic impression material?

A

Can be stretched or compressed slightly Can rebound without permanent deformation Accurately reproduce hard and soft tissue structures of the mouth

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5
Q

According to Phillips Dental Materials: What are characteristics of Elastomeric Impression Materials?

A

Rubbery polymers which are either chemically or physically cross-linked Cross-linked by either condenstaion or addition reaction

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6
Q

According to Phillips Dental Materials: What are the 4 sub -types of Elastomeric Impression Materials based on viscosity classes?

A

1 light body 2 medium body 3 heavy body 4 putty

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7
Q

According to Phillips Dental Materials: What are the 4 main types of Elastomeric Impression Material?

A

1 Polysulfide 2 Condensation Silicone 3 Addition Silicone 4 Polyether

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8
Q

According to Phillips Dental Materials: What type of impression material is VPS (vinyl polysiloxane)

A

Addition Silicone

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9
Q

According to Phillips Dental Materials: What characteristics does VPS have?

A

Addition reaction polymer is terminated with vinyl groups and is cross-linked with hydride groups activated by a platinum salt catalyst

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10
Q

According to Phillips Dental Materials: Does VPS reaction cause by-products?

A

No, it is addition polymerization NOT condensation

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11
Q

According to Phillips Dental Materials: During the VPS reaction what can occur during a secondary reaction between moisture and residual hydrides of the base polymer? What can be added to decrease this?

A

Development of hydrogen gas, this results in tiny bubbles to form in the stone if it is poured immediately A noble metal such as platinum or palladium can act as a scavanger for the released hydrogen gas

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12
Q

According to Phillips Dental Materials: Is VPS hydrophillic or hydrophobic? What is added to changes this?

A

Hydrophobic by nature A nonionic surfactant is added to render the surface of the impression hydrophilic

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13
Q

According to Phillips Dental Materials: What is the material in natural latex and some vinyl gloves to inhibit the setting of VPS impression material?

A

Sulfur contamination

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14
Q

According to Phillips Dental Materials: Working time is measured at what temperature? Setting time is measured at what temperature?

A

Working time= room temperature Setting time= mouth temperature

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15
Q

According to Phillips Dental Materials: As viscosity increases what do working and setting times do?

A

Decrease

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16
Q

According to Phillips Dental Materials: Which of the 4 types of elastomeric impression materials suffer the greatest and the least amount of linear contraction?

A

Condensation Silicone is the most Addition Silicone is the least

17
Q

According to Phillips Dental Materials: What is the chief active ingredient of alginate?

A

Soluble Aginates such as sodium, potassium or triethanolamine alginate

18
Q

According to Phillips Dental Materials: What is “dustless” alginate?

A

“Dustless” Alginate has incorporated glycerine on the alginate powder to prevent airborne fine silica poarticles that can pose a health hazard after long term exposure

19
Q

According to Phillips Dental Materials: What is the sol-gel reaction of alginate?

A

The reaction of soluble alginate with calcim sulfate and the formation of an insoluble calcium alginate gel

20
Q

According to Phillips Dental Materials: Why is a thrid water-soluble salt added to the solution for alginate?

A

To extend working time, the third salt is known as a retarder

21
Q

According to Philips Dental Materials: What are two factors that commonly influence setting time?

A

Temperature of the water Contaminates such as gypsum can acclerate the set

22
Q
A
23
Q

According to Phillips Dental Material:

What are the advantages and disadvantages of VPS?

A
24
Q

According to Phillips Dental Materials: What are the advantages and disadvantages of alginate?

A