AGD Endodontics and Pulpal Therapy 2 — Questions and Answers
Question 1: Which irrigant is most effective at dissolving necrotic pulp tissue during root canal treatment?
- Chlorhexidine 2%
- Sodium hypochlorite 5.25% (Correct answer)
- EDTA 17%
- Hydrogen peroxide 3%
Correct answer: Sodium hypochlorite 5.25%
Sodium hypochlorite is the gold standard irrigant due to its ability to dissolve organic tissue and antimicrobial properties.
Question 2: What is the primary purpose of EDTA in root canal irrigation?
- Dissolve organic tissue
- Remove the smear layer by chelating calcium (Correct answer)
- Kill anaerobic bacteria
- Lubricate hand files
Correct answer: Remove the smear layer by chelating calcium
EDTA chelates calcium ions in dentin, effectively removing the inorganic smear layer created during instrumentation.
Question 3: A patient presents with spontaneous, lingering pain that worsens with heat but is relieved by cold. What is the most likely diagnosis?
- Reversible pulpitis
- Irreversible pulpitis (Correct answer)
- Acute apical abscess
- Symptomatic apical periodontitis
Correct answer: Irreversible pulpitis
Pain that lingers after stimulus removal and relief with cold indicates irreversible pulpitis with hyperemia.
Question 4: Which obturation technique uses thermoplasticized gutta-percha injected into the canal?
- Lateral condensation
- Single cone technique
- Thermafil (Correct answer)
- Warm vertical compaction
Correct answer: Thermafil
Thermafil uses a plastic carrier coated with alpha-phase gutta-percha that is heated and inserted into the canal.
Question 5: The electronic apex locator measures which property to determine the apical constriction?
- Electrical resistance only
- Impedance using multiple frequencies (Correct answer)
- Capacitance of the periapical tissues
- Temperature gradient near the apex
Correct answer: Impedance using multiple frequencies
Modern apex locators use multi-frequency impedance measurement to accurately locate the apical constriction.
Question 6: Which condition is a contraindication to vital pulp therapy in a permanent tooth?
- Deep carious exposure with bleeding controlled in 5 minutes
- Reversible pulpitis with small mechanical exposure
- Spontaneous pain prior to treatment (Correct answer)
- Mature apex with normal periapical tissues
Correct answer: Spontaneous pain prior to treatment
Spontaneous pain indicates irreversible pulpitis or pulp necrosis, making vital pulp therapy inappropriate.
Question 7: What is the minimum recommended apical preparation size to ensure adequate disinfection in most canals?
- ISO size 15
- ISO size 25
- ISO size 35 (Correct answer)
- ISO size 45
Correct answer: ISO size 35
Research supports apical preparation to at least ISO size 35 to allow effective irrigant penetration and debridement.
AGD Endodontics and Pulpal Therapy 2
Which irrigant is most effective at dissolving necrotic pulp tissue during root canal treatment?