Endodontics
What this domain tests
Endodontics tests diagnosis, access, working length, shaping, irrigation, obturation and management of complications. The exam expects a defensible sequence rather than a list of instruments.
Core rules
- Pulp diagnosis: reversible pulpitis causes provoked pain of short duration; irreversible pulpitis causes spontaneous or prolonged pain; necrotic pulp does not respond; apical periodontitis causes tenderness and often a periapical radiolucency.
- Cold testing and electric pulp testing assess pulp vitality; percussion and palpation assess apical status. A negative response does not always mean necrosis in calcified or traumatised teeth.
- Working length is established with an apex locator plus radiograph; keep the file short of the apical constriction.
- Shaping should maintain curvature, create a smooth taper, preserve pericervical dentin and establish a glide path before rotary instrumentation.
- Sodium hypochlorite dissolves organic tissue and is antimicrobial; EDTA removes the smear layer. Use side-vented needles and never bind a needle in the canal.
- Obturation requires a fitted master cone, sealer and warm or cold lateral compaction, followed by a coronal seal.
- Emergency care: pulpotomy or pulpectomy for irreversible pulpitis; incision and drainage for abscess; antibiotics only with systemic involvement.
Worked example
A patient has severe spontaneous pain in a mandibular molar, lingering pain to cold and deep distal caries. Percussion is mildly tender, and the radiograph shows caries approaching the pulp without a periapical radiolucency. Diagnosis: irreversible pulpitis. Treatment is complete caries removal, access, pulp extirpation and shaping in the same visit if possible; a sedative dressing and waiting is inappropriate for an irreversibly inflamed pulp.
Traps
- Sodium hypochlorite extrusion can cause severe pain, swelling and nerve injury; avoid high pressure.
- A radiograph may underestimate canal curvature; confirm with an apex locator.
- Do not obturate a canal that is bleeding or exudative.
- Antibiotics do not treat pulpitis and are not a substitute for access.