ABE Endodontics flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Reversible pulpitis

Vital pulp inflammation causing sharp, brief pain provoked by cold that stops promptly after the stimulus is removed; no spontaneous pain occurs, and the pulp recovers if the irritant is eliminated.

A-delta and C fibers

Myelinated A-delta fibers at the pulp-dentin border mediate sharp, well-localized pain, whereas unmyelinated C fibers deeper in the pulp produce dull, poorly localized, lingering pain.

Reactionary versus reparative dentin

Reactionary dentin is secreted by surviving primary odontoblasts after mild irritation; reparative dentin is produced by newly recruited odontoblast-like cells after the original odontoblasts die.

Radicular cyst

An epithelium-lined cavity at the apex derived from epithelial rests of Malassez; radiographs cannot reliably separate it from a periapical granuloma, so histopathologic examination is required.

Cold test interpretation

A brief response that disappears with stimulus removal indicates vital pulp; lingering pain suggests irreversible pulpitis; no response suggests pulp necrosis or previous root canal treatment.

Electric pulp test limitation

The electric pulp test measures nerve conduction, not blood flow; calcific obliteration, immature apices, trauma, and full-coverage crowns can cause false-negative results that must be weighed with other findings.

Percussion tenderness

Pain on percussion reflects inflammation of the periodontal ligament, usually apical periodontitis; the finding does not indicate by itself whether the pulp is vital or necrotic.

Cone beam computed tomography

CBCT reveals periapical bone loss, untreated canals, root fractures, and resorption earlier than periapical films, but its higher radiation dose limits it to selected diagnostic problems.

Enterococcus faecalis

A gram-positive facultative coccus linked to persistent and secondary endodontic infections; it forms biofilms, resists alkaline medicaments such as calcium hydroxide, and survives in instrumented canals.

Endotoxin lipopolysaccharide

A gram-negative cell wall component that activates Toll-like receptor 4 on host cells, prompting cytokine release, neutrophil recruitment, and periapical bone resorption.

RANKL and osteoprotegerin

RANKL stimulates osteoclast differentiation and activation, while osteoprotegerin acts as a decoy receptor; a high RANKL-to-OPG ratio in periapical lesions favors bone resorption.

Apical constriction

The narrowest canal point near the cementodentinal junction, usually 0.5 to 1.0 mm short of the apical foramen; working length is established close to this reference.

Sodium hypochlorite actions

Dissolves necrotic tissue and is broadly antimicrobial; concentrations from 0.5 to 5.25 percent are used, with tissue dissolution and cytotoxicity increasing as concentration rises.

EDTA irrigation

A 17 percent chelating solution used as a final rinse for about one minute to remove the smear layer, open dentinal tubules, and improve penetration of irrigants and sealers.

Calcium hydroxide medicament

A strongly alkaline paste near pH 12.5 left in the canal for one to two weeks to kill residual bacteria; alone it is unreliable against Enterococcus faecalis.

Chlorhexidine substantivity

A 2 percent solution binds to dentin and provides prolonged antimicrobial action but does not dissolve tissue; direct mixing with sodium hypochlorite creates a harmful precipitate.

Coronal seal

Prevention of bacterial leakage from the oral cavity into the obturated canal; restoration quality significantly influences healing of apical periodontitis after root canal treatment.

Ferrule effect

A 1.5 to 2 mm circumferential band of dentin above the restoration margin that resists lateral forces and reduces fracture of endodontically treated teeth.

Calcium silicate sealers

Bioceramic materials that set in moisture, release calcium hydroxide, bond to dentin, and are biocompatible; they are used with single-cone or warm vertical obturation techniques.

Sodium hypochlorite accident

Extrusion of irrigant beyond the apex causes severe pain, rapid swelling, and ecchymosis; treatment is reassurance, cold compresses, analgesia, and monitoring for tissue necrosis and nerve injury.

Bypassing a separated instrument

Passing a fine file around a fragment to reestablish the glide path, permitting apical cleaning; if the canal can be disinfected, the retained fragment may be left.

Instrument separation mechanisms

Torsional fracture occurs when a file binds and exceeds its elastic limit; flexural fatigue results from repeated bending in curved canals and is reduced by limited reuse.

Root end resection

Microsurgical removal of about 3 mm of the apex with minimal bevel to eliminate the apical delta and expose canal anatomy for ultrasonic preparation and retrograde filling.

Intentional replantation

Deliberate extraction, extraoral endodontic treatment, and replacement of the tooth when other access is impractical; extraoral time must be minimized to limit ankylosis and root resorption.

Operating microscope benefit

Provides illumination and magnification that reduce osteotomy size, improve identification of fractures and untreated canals, and aid precise ultrasonic retropreparation and retrofilling.

Avulsion replantation timing

The tooth should be replanted as soon as possible; dry time under 60 minutes improves prognosis, and storage in milk or saline preserves periodontal ligament cell viability.

External inflammatory resorption

Resorption driven by infected dentinal tubules communicating with a necrotic pulp; managed by pulp extirpation, calcium hydroxide medication, and radiographic follow-up until the lesion arrests.

Regenerative endodontic procedure

For immature necrotic teeth with open apices: gentle instrumentation, low-concentration sodium hypochlorite, EDTA rinse, induced blood clot, and coronal seal, allowing continued root development.

Cervical invasive resorption

A resorptive defect in a vital tooth located below the epithelial attachment, appearing as an irregular cervical radiolucency; treated by curettage, trichloroacetic acid application, and restoration.

Articaine buccal infiltration

A 4 percent anesthetic with greater lipid solubility and bone diffusion than lidocaine; a buccal infiltration can supplement an inadequate inferior alveolar block in mandibular irreversible pulpitis.

Maximum lidocaine dose

For a healthy adult, 4.4 mg/kg to a maximum of 300 mg; epinephrine should not exceed 0.2 mg, with lower limits applied for cardiac disease.

Antibiotics for pulpitis

Not indicated for irreversible pulpitis or localized abscess without systemic signs; reserved for fever, cellulitis, spreading infection, or immunocompromise, alongside urgent dental treatment.