Dental Materials

Question 1

Pit and Fissure Sealants

Answer 1

*Success depends on technique of operator

1. clean by air polish/pumice
2. etch
3. wash and dry etched area
4. apply sealant and polymerize
5. check hardness and occlusion

Question 2

Removable Partial Denture

Answer 2

• can lose supporting teeth due to rocking
• contraindications ⇒ no supporting teeth, rampant caries, severe perio

Question 3

Casting Alloys

Answer 3

used to fabricate inlays, onlays, crowns, bridges

• precious alloys contain noble metals (gold, platinum, palladium)
• non-precious alloys contain base metals (silver, copper, nickle, tin, zinc)
• porcelain fused to metal has low thermal expansion

Question 4

Caries Classifications

Answer 4

Incipient: up to 50% of enamel

Moderate: up to DEJ

Advanced: up to 50% of dentin

Severe: past 50% of dentin

Question 5

Dental Implants

Answer 5

titanium alloys

• contraindications: bisphosphonates, AFP, immunocompromised

Pontic: Crown

Abutment: support

Screw: implant

Question 6

Transosteal Implants

Answer 6

metal framework placed through mandible

Most invasive, rarely used

Question 7

Subperiosteal Implants

Answer 7

metal framework placed over bone and under periosteum

• used when width/depth of bone in insufficient for endosseous implants

Question 8

Endosseous Implants

Answer 8

Most Common

• placed in bone
• dont probe/polish - risks breaking biological seal

Question 9

Cement Liners

(3)

Answer 9

Calcium Hydroxide: stimulates odontoblasts to lay down secondary dentin

ZOE: pulp soother; avoid saliva/oils

Resin-Modified Glass Ionomer: fluoride released, seals tubules

Question 10

Zinc Oxide Eugenol Cement

Answer 10

resin and alumina added for strength

Question 11

Zinc Phosphate Cement

Answer 11

exothermic mixing, can kill nerve/pulp

Question 12

Polycarboxylate Cement

Answer 12

temporary restoration

Question 13

Glass Ionomer Cement

Answer 13

releases fluoride

Question 14

Resin Cements

Answer 14

used for orthodontic brackets

Question 15

Hybrid Cements

Answer 15

strength and fluoride release

Question 16

Bases

Answer 16

thermal/mechanical protection to pulp

• thick to protect against thermal conductivity

Question 17

Dental Composites

Answer 17

Cosmetic

• 27-75% filler (silicates, glass, quartz)
  
  • less filler = more aesthetic
• wear resistant
• permits micromechanical retention

Question 18

Gypsum Types

(5)

Answer 18

Type 1: mounting impression plaster

Type 2: model plaster

Type 3: dental stone

Type 4: high strength, low expansion dental stone (crowns)

Type 5: high strength, high expansion dental stone

Question 19

Rigid Impression Materials

Answer 19

Used in edentulous areas

Hardens quickly, stuck if not removed in time

plaster, compound, ZOE

Question 20

Water Insoluble Impression Materials

(4)

Answer 20

Flexible

polysulfide rubber

polyether rubber

silicone rubber

polyvinyl siloxane

Question 21

Water Soluble Impression Materials

(2)

Answer 21

Flexible

agar-agar

alginate

Question 22

Amalgam Alloys

Answer 22

• usually silver
• amalgamator used for mixing
• high thermal conductivity (causes sensitivity)
• tin oxide used to polish *

Question 23

Dental Amalgam

Answer 23

Class 1 and 2 restorations

• high compressive strength
• tarnish, corrode, creep due to excessive force
• polish with tin oxide after 24hrs*

Question 24

Bonding Agents

Answer 24

Fail due to saliva or oil contamination

• etching - 37% phosphoric acid
  
  • mechanical attachment to tooth
  • chemical attachment to agents
• amalgam bonding increases retention and decreases microleakage

Question 25

Periodontal Dressings

Answer 25

cast-like material to maintain contouring

protection for 10-15 days

white patches due to eugenol is common

Question 26

compressive strength

Answer 26

capacity of a material to withstand force

Question 27

cohesion

Answer 27

internal strength of an adhesive due to interactions within the

adhesive that bind the mass together