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NBDE Part II > Endodontics > Flashcards

Flashcards in Endodontics Deck (36)
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1
Q

Pulpal Inflammation (not infection)

A
  • Insidious process
  • No direct insult to pulp, thus chronic infection (no PMN, only plasma cells, lymph, MO)
  • Most common and earliest symptom: thermal sensitivity (NOT percussion, throb, or persistent discomfort) due to dentin involvement!

If pulp was exposed, then an acute run occurs

2
Q

Vital vs non-vital pulp and bacteria

A
  • Vital pulp can withstand bacteria invasion during an exposure (in 2 weeks, only 2 mm of coronal pulp is infected)
  • Non-vital pulp is a fertile ground
3
Q

CaOH pH

A

pH = 12.5

- leads to necrosis. This necrosis is meant to cause hard tissue repair with odontoblasts laying down reparative dentin.

4
Q

Chronic apical abscess vs cyst or granuloma

A

cyst or granuloma have a defined radiolucent border
All are asymptomatic

NOTE: Tx for Acute Abscess is I&D first, then return for RCT to provide patient comfort. In Chronic Abscess, no need to I&D b/c patient is asymptomatic.

Apical Trephination = taking a 15 file and making a fistula through he soft tissue via the canals and extend past the apex

Surgical Trephination = perforating the bone with a round bur to make a fistula

5
Q

Thermal test

A

Lingering if over 15 sec

COLD

  1. cold water bath
  2. ice or CO2 sticks
  3. ENDO ice = DDM (dichlorodifluoromethane)
  4. Ethyl Chloride

HOT

  1. Gutta percha
  2. hot water bath
  3. rubber wheel with a hand piece

NOTE: trauma teeth may develop PA radiolucencies later on, but can still be vital!

EPT

  • contraindicated with pacemakers
  • False (+) = pus, nervous patient, moisture
  • False (-) = trauma, open apex, restorations which insulate, analgesic Rx.
  • A low reading will be seen with reversible pulpitis

An EPT only determines that some A delta fibers are still active, not about vasculature. Some necrotic pulps will have firing A delta fibers.

6
Q

Internal vs External resorption

A

Internal (PINK TOOTH)

  • Asymptomatic, incidental finding
  • From inflammation due to infected pulp from trauma
  • Pulp must be vital for this to occur, however, pulp test may be negative.
  • CAUSES: Trauma (pulpal), decay, CaOH direct pulp cap, cracked tooth
  • NOTE: an x-ray may show an external (cervical) reposition as an internal one, so take a different angle x-ray

External = cervical resorption (if located at CEJ)

  • CAUSES: Trauma (PDL), PA inflammation, excessive ortho forces, tooth impaction, internal bleaching
  • Seen as Bowl-shaped areas of resorption involving cementum and dentin
  • Tx: RCT. Obtruded with CaOH and replaced every 3 months for 1 year. May continue with permanent gutta percha if resorption has stopped.
7
Q

Types of resorption

A
  1. Replacement = progressive ankylosis due to excessive trauma to the PDL apparatus (no PDL or commute layer is present between dentin and bone)

SIGNS: No mobility, metallic sound to percussion, infra-occlsuion in a developing dentition.

MOST common in unsuccessful replant cases

  1. Surface = Acute (not progressive) injury to PDL.
    - Self limiting to cementum
    - Reversible
    - Not seen radiographically
8
Q

Pulp cells, fibers and layers

A

Type 1 > Type 3 collagen&raquo_space; Type 5 collagen

  • Dentin has [Type 1]
  • Odontoblast make Type 1
  • [Fibroblasts] make both Type 1 and 3
  • Histiocytes (MO), ymphocytes

FIBERS:
1. myelinated = sensory = A delta (enter at apex then forms the plexus of Raschkow. In the plexus, it becomes unmyelinated) = quick, sharp, monetary pain that does not linger. A delta fibers + odontoblast layer = pulpodentinal complex. A-delta fibers are tested with EPT tests (no cardiac pacemaker!)

  1. unmyelinated = motor (vasodilation) = C-fibers = enter with the A-delta fibers at apex and are though out the pulp = burning, ache, throb = high threshold = noci-ceptive fibers (pain to prevent injury) = excitable even in necrotic tissue = stimulated by HEAT = shows irreversible local damage.
  2. free NERVE ENDING = pain (thus, regardless of pressure, hot or cold, response is always pain)
  3. Reticular fibers = decrease with age
  4. Collagen fibers = increase with aged to calcifications

ZONES: inner to outer
1. central zone = pulp proper (Large BV, nerves)
2. cell rich (fibroblasts)
3. cell free = zone of weil (capillaries and Raschkow nerve plexus)
4. Odontoblastic layer
(next layer is predentin which is unmineralized and predisposes denin to internal resorption)

  • Primary pulp function is formation of dentin via induction (forms dentin which forms enamel) and nutrition.
  • Pulp lacks collateral circulation (thus is prone to necrosis)
9
Q

Dentin types

A
  1. Mantle = first formed before odontoblast layer is organized
  2. Circumpulpal = most dentin
  3. Secondary = Forms after tooth eruption and throughout life –> asymmetric, irregular reduction in pulp size as a person ages
  4. Tertiary = reparative = irregular, disorganized due to stimuli
  5. Pre-dentin = not mineralized, 47 microns right near the pulp

Primary dentin = forms prior to apex closure
secondary = after closure
Junction between the two shows a sharp change in direction of the dentinal tubles.

10
Q

Pulp Stone

A

Chronic result of stimulus (decay or large restoration)

11
Q

Tx of perforations

A

control heme (NOT with formecresol) –> temporarily seal (Cavit, ZOE, decal = if its so large) –> continue with RCT –> Restore later

If sub-crestal, seal first to prevent leakage into tooth.

12
Q

Vertical root fracture

A
  • x-rays show a radiolucent halo uniformly surrounding the entire root
  • Clinical exam will show a persistent periodontal defect
  • Most are due to iatrogenic causes

NOTE: Horizontal fractures do not automatically require RCT is asymptomatic and no pulp necrosis.

13
Q

Problem with endodontic implants?

A

no apical seal

14
Q

What is root submersion used for?

A

maintain bone height (RCT roots are submerged and full thickness flap laid over top)

15
Q

When does the apex of a tooth close?

A

2-3 years post eruption

16
Q

What is the sequela of PA infection?

A

osteomyelitis (rare)

  • Tends to be more diffuse in the mandible than the maxilla
  • Acute onset with pain, fever
  • X-ray shows “moth eaten” pattern
  • Tx: I&D, Antibiotics
17
Q

Retrofill materials (places an apical seal, post apicoectomy, used in calcified canals that cannot be shaped)

A
  1. MTA (mineral trioxide aggregate)
    - Ca + P
    - High pH –> hard tissue induction
    - PRO: Biocompatible, good seal
    - CON: difficult to manipulate, sets too long
  2. zinc free amalgam
18
Q

Most common cause of reverse fill/retrograde fill endo?

A

Current post in a tooth that needs re-treatment.

19
Q

Periodontal abscess

A
will respond (+) with pulp vitality (unlike an apical abscess)
(+) percussion, (+) palpation
20
Q

Canal shapes with files

A

reaming (repeated rotation) action

  • makes a rounded canal shape
  • engine driven files only use this motion
  • silver fill cones

filing (push and pull, scrape walls) action

  • irregular shape
  • removes dentin
  • Gutta percha

circumferential filing = best way to prevent ledges

21
Q

Obturation should end where (be the narrowest)?

A

Dentin-cementum junction which is 0.5 - 1.0 mm from apical foramen

22
Q

Endo Sealer Types:

A
  1. ZOE = biocompatible with soft tissue. But causes staining, slow setting, non-adhesive and is soluble.
23
Q

Most common cause of RCT failure?

A

incomplete disinfection of the canals

2nd cause: leakage in an incompletely obturated canal

NOTE: Most teeth with RCT are lost due to restorative failure, not the RCT itself

If you see a PA region grow after removal of the granuloma/cyst and RCT, its due to leakage.

24
Q

Chelators

A
  1. 17% EDTA
    - remove mineralized portion of smear layer (calcified tissue only, thus safe for ST)
    - opens dentinal tubules
    - works for 5 days until the chelator is used up, thus must be irrigated when canal shaping is done
    - Replaced Ca with Na to make softer canals for proper enlargement
  2. EDTAC (Cetavlon)
    - Has greater anti-microbial potential, but is more inflammatory than EDTA
    - NaOCl is the inactivator
  3. RC-Prep
    - EDTA + Urea Peroxide (Irrigation)
25
Q

chloroform in Endo

A

dissolve gutta percha during re-treatment and on solvent-softened custom cones

26
Q

Irrigants

A
  1. 5.25% NaOCl = toxic to vital tissue
  2. 3% H2O2 = effervescent effect
  3. Urea Peroxide = tolerated by ST more than NaOCl, and greater solvent/germicidal action than H2O2.
27
Q

Internal bleaching

A
  1. 30% H2O2 in alkaline medium
  2. Walking black = sodium perborate with water = kept in patient’s tooth for 4-5 days with a temporary restoration, removed and process repeats. Safer than Superoxol.
  3. 30% Superoxol = potent oxidized of stain-producers
  4. Chairside: Heat + Superoxol = Heat liberates the oxygen

Bleach changes enamel and dentin color

RISK:
External = Cervical root resorption. Recalls are a must to monitor after bleaching.
Acute apical periodontist if canals are not fully obturated

Other tooth whitening:
Chair-side: 35% H2O2 light-activated in 4-10 minute cycles
Rx: 10% Carbamide Peroxide
OTC: H2O2

  • Can go into dentin
  • Worst response Grey (tetracycline → use composite)
  • Extrinsic Stains = Chromogenic bacteria in plaque , tea, tobacco, amalgam
  • Intrinsic Stains = tetracycline, fluoride, dentogenesis imperfect
  • WATER PICKS remove non-adherent bacteria better than brushing
28
Q

What are the only 2 health contraindications for RCT?

A
  1. Uncontrolled diabetes

2. Very recent MI (6 months)

29
Q

Best prognosis for root fractures

A

Horizontal > Vertical
Apical root > midroot > coronal root
Oblique > Transverse

30
Q

Why are endo teeth weak?

A

Not because they are brittle (actually stay moist up to 10 years), but bc of loss of tooth structure

31
Q

Pulp chamber retained amalgam requires ___ mm of amalgam in each canal for retention.

A

3 mm in each canal

32
Q

Patient recently received on inlay and has pain on biting. Occlusion is good, but painful.

A

Fractured cusp.

33
Q

Pulpal involvement is confirmed, but x-rays do not show an offender. Deep pockets noted.

A

Vertical root fracture

34
Q

What does 25.02 K file mean?

A
D1 = where cutting blades begin
D2 = where the flutes that extend up the shaft for 16 mm come to a stop (Length of cutting edges are always 16 mm)

A 0.02 taper file increases in diameter by 0.02 mm every millimeter up from the tip

Ex: 25.02 file means

  • 0.25mm at the tip (D1)
  • 0.27mm for 1 mm up from the tip, 0.29mm for 2 mm up from the tip, etc.
  • Total cutting length is 16 mm
  • 15-White
  • 20-Yellow
  • 25-Red
  • 30-Blue
  • 35-Green
  • 40-Black
  • 45-White (color sequence repeats as you increase in size)
35
Q

Zones of Carious Dentin

A
  1. Normal Dentin
  2. Subtransparent Dentin: demineralized from acid, but not infected with bacteria and is capable of remineralization
  3. Transparent Dentin: softer, but otherwise exactly the same as sub transparent dentin. No need to remove.
  4. Turbid Dentin: bacterial invasion, not capable of remineralization
  5. Infected Dentin: outermost zone that is decomposed dentin.
36
Q

Zones of Incipient lesions

A
  1. Surface: unafected
  2. Body: largest portion. Demineralized
  3. Dark: no polarized light. Demineralized + Mineralized area
  4. Translucent: Deepest zone, advancing front of decay