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BDS2 CLINICAL Dental Materials > Introduction to DMS > Flashcards

Flashcards in Introduction to DMS Deck (56)
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1

what does the behavior of dental materials affect

selection
preparation
placement
performance
patient expectations

2

what indicates that a material is safe

CE mark

3

what are the different types of restorative materials

amalgam
composites
glass ionomer cements
composers
porcelain

4

what are the different impression materials

impression compound
impression paste
hydrocolloids
elastomers

5

what is the hydrocolloid impression material

alginate

6

what are the elastomers

polysulphides
polyethers
silicones

7

what are the different metals/alloys

amalgam
cobalt chromium
titanium
gold
stainless steel

8

what is composite like initially and finally

initially flows out of a cartilage - low to high viscosities available
finally sets with margins and hardens

9

what is impression material (polyether) like initially

initially flows into a tray and low viscosity

finally undergoes a setting reaction to become firm and stable

10

where is stainless steel used

denture base
orthodontic appliances

11

when is cobalt chromium used

partial dentures

12

what are the different properties of materials

mechanical, chemical, physical

13

what may forces applied to materials cause it to do

stretch/compress
deform (temp or permanent)
fracture

14

what is the equation for force

F = mass (kg) x gravitational acceleration

15

what are the types of forces

compressive
tensile
shear

16

what is the equation for stress

force/unit area

17

what is the equation for strain

change in length/original length

18

what is the definition of stress

force per unit cross sectional area that is acting on a material

19

what is the definition of strain

fractional change in the dimension caused by the force

20

what happens if the stress and strain exceed the maximum value that the material can withstand

fracture is most likely

21

what is the proportional limit

it is up until the proportional limit that stress and strain are linearly related

22

what is youngs modulus

measure of stiffness/rigidness of a material

23

what are the different mechanical properties

hard/soft
brittle/ductile
strong/weak
rigid/flexible

24

what are the mechanical properties of enamel

brittle
rigid
strong
hard

25

what are materials subjected to

biting
grinding/chewing
removal

26

how does biting affect materials

compressive force applied to upper tooth when biting. Can the tooth withstand the force or will it fracture?

27

how does grinding/chewing affect materials

tooth slides along the surface of the other. Frictional forces are experienced. Will tooth surface be abraded resulting in the loss of layers of enamel?

28

what is the typical biting force

500 to 700N (50-70kg)

29

how can materials be subject to removal

the material needs to adhere to enamel or it will be removed by masticatory forces – the forces will overcome the bond between material and tooth structure. This is through shear force

30

how do the mechanical properties of enamel and dentine compare

Enamel is more rigid than dentine as it has a higher EM. The fracture stress of enamel is greater than dentine.