Endodontics Flashcards

What is considered the most common biological cause of post-treatment endodontic failure?

Answer: Residual bacteria persisting within the root canal system

Residual bacteria surviving within the complex root canal anatomy after treatment is the primary biological cause of persistent periapical pathology and endodontic failure.

Which obturation material remains the gold standard for filling root canals in conventional endodontic treatment?

Answer: Gutta-percha with a root canal sealer

Gutta-percha combined with a root canal sealer is the gold standard obturation material due to its biocompatibility, dimensional stability, radiopacity, and ease of removal if retreatment is required.

What is a 'ledge' as a complication in endodontic treatment?

Answer: An artificial step created in the canal wall preventing further instrument progress

A ledge is an iatrogenic shelf or false pathway created on the canal wall, most often in curved canals, which prevents instruments from reaching the established working length.

If a sodium hypochlorite injection accident occurs with extrusion beyond the apex, what is the most appropriate immediate management?

Answer: Stop irrigation immediately and manage pain and swelling conservatively

Immediate management involves stopping irrigation, providing pain relief, applying ice to reduce swelling, and monitoring; most cases resolve with conservative management, with hospital referral reserved for severe or progressive cases.

What is the principle behind the step-back technique in root canal preparation?

Answer: Preparing the apex first then using progressively larger files coronally to create a taper

The step-back technique involves establishing the working length and preparing the apical third first, then 'stepping back' with successively larger files coronally to develop a funnel-shaped taper.

Which microorganism is most strongly associated with persistent and treatment-resistant endodontic infections?

Answer: Enterococcus faecalis

Enterococcus faecalis is associated with persistent endodontic infections because it resists calcium hydroxide medicaments, survives in nutrient-poor environments, and adheres strongly to dentinal walls.

Which radiographic appearance is most characteristic of a chronic apical periodontitis lesion?

Answer: Well-defined radiolucency at the root apex

Chronic apical periodontitis presents as a well-defined (or sometimes ill-defined) periapical radiolucency representing bone destruction secondary to chronic infection from a necrotic pulp.