Endodontics Flashcards
Pulpal Inflammation (not infection)
- 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
Vital vs non-vital pulp and bacteria
- 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
CaOH pH
pH = 12.5
- leads to necrosis. This necrosis is meant to cause hard tissue repair with odontoblasts laying down reparative dentin.
Chronic apical abscess vs cyst or granuloma
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
Thermal test
Lingering if over 15 sec
COLD
- cold water bath
- ice or CO2 sticks
- ENDO ice = DDM (dichlorodifluoromethane)
- Ethyl Chloride
HOT
- Gutta percha
- hot water bath
- 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.
Internal vs External resorption
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.
Types of resorption
- 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
- Surface = Acute (not progressive) injury to PDL.
- Self limiting to cementum
- Reversible
- Not seen radiographically
Pulp cells, fibers and layers
Type 1 > Type 3 collagen»_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!)
- 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.
- free NERVE ENDING = pain (thus, regardless of pressure, hot or cold, response is always pain)
- Reticular fibers = decrease with age
- 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)
Dentin types
- Mantle = first formed before odontoblast layer is organized
- Circumpulpal = most dentin
- Secondary = Forms after tooth eruption and throughout life –> asymmetric, irregular reduction in pulp size as a person ages
- Tertiary = reparative = irregular, disorganized due to stimuli
- 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.
Pulp Stone
Chronic result of stimulus (decay or large restoration)
Tx of perforations
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.
Vertical root fracture
- 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.
Problem with endodontic implants?
no apical seal
What is root submersion used for?
maintain bone height (RCT roots are submerged and full thickness flap laid over top)
When does the apex of a tooth close?
2-3 years post eruption
What is the sequela of PA infection?
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
Retrofill materials (places an apical seal, post apicoectomy, used in calcified canals that cannot be shaped)
- MTA (mineral trioxide aggregate)
- Ca + P
- High pH –> hard tissue induction
- PRO: Biocompatible, good seal
- CON: difficult to manipulate, sets too long - zinc free amalgam
Most common cause of reverse fill/retrograde fill endo?
Current post in a tooth that needs re-treatment.
Periodontal abscess
will respond (+) with pulp vitality (unlike an apical abscess) (+) percussion, (+) palpation
Canal shapes with files
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
Obturation should end where (be the narrowest)?
Dentin-cementum junction which is 0.5 - 1.0 mm from apical foramen
Endo Sealer Types:
- ZOE = biocompatible with soft tissue. But causes staining, slow setting, non-adhesive and is soluble.
Most common cause of RCT failure?
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.
Chelators
- 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 - EDTAC (Cetavlon)
- Has greater anti-microbial potential, but is more inflammatory than EDTA
- NaOCl is the inactivator - RC-Prep
- EDTA + Urea Peroxide (Irrigation)
chloroform in Endo
dissolve gutta percha during re-treatment and on solvent-softened custom cones
Irrigants
- 5.25% NaOCl = toxic to vital tissue
- 3% H2O2 = effervescent effect
- Urea Peroxide = tolerated by ST more than NaOCl, and greater solvent/germicidal action than H2O2.
Internal bleaching
- 30% H2O2 in alkaline medium
- 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.
- 30% Superoxol = potent oxidized of stain-producers
- 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
What are the only 2 health contraindications for RCT?
- Uncontrolled diabetes
2. Very recent MI (6 months)
Best prognosis for root fractures
Horizontal > Vertical
Apical root > midroot > coronal root
Oblique > Transverse
Why are endo teeth weak?
Not because they are brittle (actually stay moist up to 10 years), but bc of loss of tooth structure
Pulp chamber retained amalgam requires ___ mm of amalgam in each canal for retention.
3 mm in each canal
Patient recently received on inlay and has pain on biting. Occlusion is good, but painful.
Fractured cusp.
Pulpal involvement is confirmed, but x-rays do not show an offender. Deep pockets noted.
Vertical root fracture
What does 25.02 K file mean?
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)
Zones of Carious Dentin
- Normal Dentin
- Subtransparent Dentin: demineralized from acid, but not infected with bacteria and is capable of remineralization
- Transparent Dentin: softer, but otherwise exactly the same as sub transparent dentin. No need to remove.
- Turbid Dentin: bacterial invasion, not capable of remineralization
- Infected Dentin: outermost zone that is decomposed dentin.
Zones of Incipient lesions
- Surface: unafected
- Body: largest portion. Demineralized
- Dark: no polarized light. Demineralized + Mineralized area
- Translucent: Deepest zone, advancing front of decay
