Endodontic materials

Question 1

2 materials used for endo instruments

Answer 1

nickel titanium
stainless steel

Question 2

what does the size of a hand instrument represent

Answer 2

the diameter of the tip

Question 3

what size is the tip on a size 10 hand file

Answer 3

0.1mm

Question 4

how much bigger is D16 to D0

Answer 4

0.32mm greater

Question 5

what is the tip angle on a hand instrument

Answer 5

75 degrees

Question 6

what is the taper on a SS hand instrument

Answer 6

0.02
2%

Question 7

what does a taper of 0.02 mean

Answer 7

every 1mm towards the shank, the diameter increases by 0.02

Question 8

what are the available lengths of SS files

Answer 8

21, 25 or 31mm

Question 9

what is the consistent working length of SS hand file

Answer 9

16mm

Question 10

what is the increase in diameter from file to file, from sizes 10-60

Answer 10

0.05mm

Question 11

what is the size increase from file to file, from sizes 60 - 140

Answer 11

0.1mm

Question 12

SS hand file metal composition

Answer 12

10.5% chromium

Question 13

disadvantages of SS hand files

Answer 13

poor flex

Question 14

advantages of SS hand files

Answer 14

dont corrode rust or stain

Question 15

types of SS files

Answer 15

K file
flexofile
hedstrom file

Question 16

what are barbed broaches used for

Answer 16

removing pulpal tissue - not suitable for narrow, curved canals

Question 17

flexofile use

Answer 17

preparation of glide path
apical gauging
negotiating ledges

Question 18

tip on a flexofile

Answer 18

nonaggressive (batt)

Question 19

what motion are hedstroem files used in

Answer 19

up and down motion due to stiffness

Question 20

when are hedstroem files used

Answer 20

only in retreatment to remove GP or an overfilling of root canal

as the file cuts when moved in the coronal direction

Question 21

what do NiTi files require

Answer 21

torque control motor

Question 22

metal composition of NiTi

Answer 22

56% nickel
44% titanium

Question 23

what are the new NiTi files made of

Answer 23

M wire

Question 24

what are the 3 crystalline phases of M wire

Answer 24

deformed and microtwinned martensite
premartensitic R-phase
austenite

Question 25

advantanges of M wire

Answer 25

greater flex increased safety

Question 26

by how much is cyclic fatigue improved with M wire

Answer 26

400%

Question 27

rotation speed and torque of proglider

Answer 27

300 rpm torque 2

Question 28

what lengths are protaper gold instruments available in

Answer 28

21mm 25mm 31mm

Question 29

what is used as an interappointment medicament

Answer 29

non-setting calcium hydroxide paste

Question 30

pH of calcium hydroxide

Answer 30

12.5-12.8

Question 31

commercial names of CaOH

Answer 31

hypocal ultracal

Question 32

symptoms of a canal with exudate

Answer 32

TTP and tender to percussion discharge present at each canal opening

Question 33

apexification

Answer 33

open apex tooth is filled with calcium hydroxide to stimulate the formation of a hard tissue barrier at the apical portion of the root

Question 34

indications for apexification

Answer 34

vital radicular pulp in an immature tooth pulpotomy if vital pulp tissue is present apically pulpless immature tooth with or without periapical radiolucency horizontal root fracture (80% success)

Question 35

what is used for apexification

Answer 35

mineral trioxide aggregate

Question 36

what would be used to induce hard tissue formation in the presence of iatrogenic perforation

Answer 36

CaOH

Question 37

Internal resorption tx

Answer 37

if not perforated - extripate pulp, dress CaOH, obturate with warm GP if perforated - defect sealed, surgically or with MTA

Question 38

what does internal resorption present as

Answer 38

pink spot

Question 39

types of external resorption

Answer 39

surface resorption inflammatory resorption replacement resorption pressure resorption systemic resorption idiopathic

Question 40

tx for non vital immature permanent incisors

Answer 40

apexification apical barrier revascularisation

Question 41

GP composition

Answer 41

19-22% gutta percha 59-75% zinc oxide waxes, coloring, antioxidants and metallic salts

Question 42

what is GP

Answer 42

trans isomer of polyisoprene (rubber)

Question 43

what are the 2 forms of GP

Answer 43

beta phase - solid alpha phase - heated, becomes soft

Question 44

GP disadvantages

Answer 44

shrinkage on cooling poor adhesion to dentine cant be heat sterilized

Question 45

types of sealers

Answer 45

zinc oxide eugenol calcium hydroxide GI epoxy resin

Question 46

Types of calcium silicate cements

Answer 46

1st gen - MTA 2nd gen - biodentine, bioaggregate