Apd

Front 1

Access prep need to be:

Back 1

no undercuts

smooth axial walls

all canals visible

funnel shaped

straight line access

safe irrigation

straighten out curves

Front 2

disadvantages of traditional files

Back 2

produce narrow canals

increasingly inflexible as they increase in size

canals are rarely an 02 taper

use a lot of instruments,

if continually rotated they will fracture

can easily create ledges

can push debris into the canal and cause blockages

very time consuming

Front 3

NiTi File properties

Back 3

super elastic metal

used in a continuous motion

have modified cutting edges to prevent binding in the canal

non cutting tips which allow the files to remain centred in the canal

have radial lands which prevents locking in the dentine

rake angle is usually negative or neutral

the grooves allows removal of debris

however do produce a thick smear layer

used for canal enlargement not negotiation

Front 4

protaper file properties

Back 4

triangular cross section, active cutting blades, blunt tip

shaper x file = 3.5-19% taper up to 9mm then 2% taper 10-14mm

shaper 1 file = 2-11% taper up to 14mm

shaper 2 file = 4-11.5% taper up to 14mm

Front 5

contraindication for using rotary files

Back 5

tight or sclerosed files,

very curved canals

s-shaped canals

apical hooks

canals with sharp elbows

if a glide path cannot be formed

Front 6

advantages of NiTi files

Back 6

less canal transportation

flexible

good deep shape

less debris extrusion

faster

fewer files used

more predictable results

Front 7

disadvantages of NiTi files

Back 7

torsional and flexural failures and fractures

Front 8

methods for determining working length

Back 8

tactile feedback

paperpoint technique

radiographic

electronic apex locator

Front 9

Types of Apex

Back 9

anatomical

radiographical

major apical constriction

minor apical constriction

CDJ

Front 10

problems with electronic apex locators

Back 10

metallic restorations short circuit the system

perforation trigger a response

large canals can cause misreading

Front 11

most common pathways for bacterial entry into the canal

Back 11

caries

cracks

exposed dentine

broken down restorations

Front 12

reasons for placing an interim restoration

Back 12

structural integrity

support for weakened cusps

coronal seal

rubber dam easy to apply

ideal cavity can be cut

no risk of leaking irrigants

a temp restoration will be better retained

more comfortable and functional for the patient

can be used as a core for an indirect restoration

Front 13

why would you remove a crown before endo?

Back 13

can thoroughly asses the underlying tissue

identify hidden pathology

better orientation

better coronal seal

Front 14

main requirements of a temporary restoration

Back 14

good coronal sela

easily removable

obvious difference between this and tooth tissue/interim restoration

inexpensive

Front 15

why protect posterior teeth undergoing endo?

Back 15

reduced tooth structure

access cavity

loss of marginal ridges

axial forces can flex cusps

non-axial forces are even more damaging

Front 16

options for protecting posterior teeth

Back 16

occlusal adjustment

cusp reduction and overlay

onlay/overlay indirect restoration

full crown

Front 17

properties of irrigants

Back 17

kills and removes bacteria

removes debris/nectrotic/inflamed tissue

removes dentine debris and smear layer

provides lubrication

Front 18

obstacles in the way of irrigation

Back 18

anatomical complexities

smear layer

fluid dynamics

biofilm

resistant microbiota

Front 19

smear layer consists of...

Back 19

inorganic and organic substances,

odontoblast processes,

bacteria

necrotic debris

it provides protection for bacteria

Front 20

what kind of needle used to irrigate and why?

Back 20

side venting size 27/30 gauge needle and luer lok syringe

stop locking into the canal and stops apical pressure

Front 21

ideal characteristics of an endo irrigant

Back 21

effective microbial action

non-irrigating to the periapical tissue

stable in solution

prolonged antimicrobial action

active in the presence of blood/proteins/serum

low surface tension

not interfere with periapical healing

not stain tooth tissue

not cause allergic reaction

completely remove smear layer

non toxic, non-antigenic, non-carcinogenic

no reaction with filling materials

easy to use

inexpensive

Front 22

types of irrigant and strengths

Back 22

NaOCl - 1.25%

EDTA - 17%

Chlorhexidine - 0.2-2%

Iodine potassium iodide - 2% iodine in 4% potassium iodide

hydrogen peroxide 3-5%

MTAD - 3% doxycycline, 4.25% citric acid

Photo activated disinfection

electronically activated water

Front 23

NaOCl advantages and disadvantages

Back 23

advantages:

dissolves organic matter and biofilm, antimicrobial, affordable

Disadvantages:

minimally removes smear layer, reduces flexural strength of dentine, can cause allergies, toxic to vita tissues, corrodes metal instruments

Front 24

EDTA Advantages and disadvantages

Back 24

advantages: removes smear layer (use as penultimate rinse), non-toxic, eventually kills bacteria by starvation of metal ions

disadvantages: not bactericidal, overuse causes excessive removal of dentine

Front 25

Chlorhexadine advantages and disadvantages

Back 25

advantages: broad spectrum, cationic bibiguanide antiseptic, persistant activity, less toxic than NaOCl, no harmful effects to dentine

disadvantages: forms brown precipitate with NaOCl, no tissue dissolving effects, cannot remove smear layer, potential for allergic reaction

Front 26

iodine potassium iodide advantages and disadvantages

Back 26

advantages: broad antimicrobial spectrum, low toxicity, used in re-treatment

disadvantages: can stain dentine, not stable in presence of organic material, no tissue dissolving properties, unable to remove smear layer

Front 27

hydrogen peroxide advantages and disadvantages

Back 27

advantages: free radicals (OH*) destroy proteins, active against bacteria, yeasts, viruses

disadvantages : antimicrobial and tissue dissolving less than NaOCl, can release bubbles and cause emphysema, nolonger used as routine

Front 28

MTAD advantages and disadvantages

Back 28

Mixture of tetracycline, acid and detergent

advantages: borad spectrum antimicrobial, acid removed smear layer, no adverse effects on the tooth

disadvantages: less efficient on biofilm, more toxic than NaOCl, expensive, risk of bacterial resistance and tetracycline staining

Front 29

reversible pulpitis signs and treatment

Back 29

pain form hot, cold, sweet, short duration, doesn't linger, difficult to localise, no pa radiolucency, exaggerated response to vitality testing

treat the causative factor, tell them to take analgesics and pain will reduce

Front 30

irreversible pulpitis signs and treatment

Back 30

spontaneous pain that lasts for hours, triggered by heat, reliveed by cold, kept awake at night, ttp, pain radiates and can get worse

treatment: try and complete RCT

Front 31

Hot pulps - alternatives to normal LA

Back 31

regional anaesthesia, lignocaine and articaine, intraligamentary, intra pulpal, intraosseous, sedation

Front 32

periapical periodontitis - signs and treatment

Back 32

tender to percuss and palpate, swelling and reddening of the mucosa, to response to vitality testing, pain severe in function, can be constant or worsening, can be present for hours

treat by placing CaOH and bacteria tight seal and re-visiting

Front 33

acute apical abscess - signs and treatment

Back 33

swelling, pain on pressure, feeling of the tooth being elevated in the socket, mobility, lymphadenopathy, fever, malaise,

treat by drainage though incision, extraction or rct, give antibiotics at signs of spreading infection

Front 34

cracked tooth - causes, signs, treatment

Back 34

caused by mastication, bruxism, thermal cycling

signs - pain on chewing, sensitivity to hot and cold, difficult to locate pain, fracture line mesial to distal

treat with ortho band, replace restoration, rct if needed.

Front 35

complicated crown fracture in permanent teeth treatment

Back 35

pulp capping

partial pulpotomy

rct

Front 36

primary teeth pulp treatment

Back 36

extraction
vital pulp = indirect pulp cap

no-vital tooth = pulpectomy

Front 37

principles of electronic apex locators

Back 37

2 or more currents are varying frequency are emitted, the impedence of the tissues surrounding the file is compared to the impedence of the buccal mucosa. when the values match then the file is deemed to be at the apex

Front 38

why can it be difficult to anaesthetise in pulpitic cases

Back 38

afferent nerve fibres from inflamed tissues have changing resting potentials, lowered excitability thresholds, difficult for la to prevent total nerve transmission, patients under stress have lowered pain threshold, accessory innervation