Endodontics Flashcards

Which irrigant is considered the gold standard for root canal disinfection due to its ability to dissolve organic tissue?

Answer: Sodium hypochlorite 2.5–5.25%

Sodium hypochlorite is the gold standard root canal irrigant because it has broad antimicrobial activity and is the only irrigant capable of dissolving necrotic pulp tissue.

What is the primary reason for using a rubber dam during endodontic treatment?

Answer: To prevent instrument aspiration and maintain asepsis

The rubber dam isolates the tooth from oral flora to maintain asepsis and prevents potentially fatal aspiration of endodontic instruments.

Which feature best distinguishes symptomatic irreversible pulpitis from reversible pulpitis?

Answer: Spontaneous pain and lingering pain after stimulus removal

Symptomatic irreversible pulpitis is characterised by spontaneous pain and pain that lingers for 30 seconds or more after removal of the stimulus, indicating irreversible pulpal damage.

How does an electronic apex locator determine the working length of a root canal?

Answer: By measuring impedance between the file tip and oral mucosa

Electronic apex locators measure the electrical impedance between an instrument tip in the canal and an electrode placed on the oral mucosa, which changes predictably at the apical constriction.

What is the primary function of EDTA in root canal treatment?

Answer: To remove the smear layer by chelating calcium ions from dentine

EDTA is a chelating agent that removes the smear layer produced during instrumentation by binding calcium ions from the inorganic dentine component.

Which cells are responsible for producing reactionary (secondary) dentine in response to pulpal irritation?

Answer: Odontoblasts

Odontoblasts, which line the pulp-dentine junction, are responsible for continued dentine formation throughout life and produce reactionary dentine in response to injury.

What is the most appropriate immediate management for an acute apical abscess with spreading cellulitis and systemic signs of infection?

Answer: Drainage, systemic antibiotics, and definitive endodontic treatment or extraction

Spreading infection with systemic involvement requires both surgical drainage and systemic antibiotics; antibiotics alone are insufficient without addressing the source, and definitive treatment follows once acute symptoms resolve.