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
