Endodontics
Diagnosis and working length
Pulpal diagnosis (AAE): normal, reversible pulpitis (sharp, provoked, resolves in seconds), symptomatic irreversible pulpitis (spontaneous pain or lingering more than 30 seconds), asymptomatic irreversible, necrotic, previously treated. Periapical diagnosis includes symptomatic/asymptomatic apical periodontitis, acute and chronic apical abscess, and condensing osteitis. Working length is the apical constriction, 0.5–1.0 mm short of the radiographic apex. Electronic apex locators are reliable except with pus, blood or a very wide foramen, and should always be confirmed radiographically.
Irrigation and shaping
Shaping produces a continuously tapering canal with apical patency; NiTi rotary files reduce transportation. Sodium hypochlorite (0.5–5.25%) dissolves organic tissue and destroys biofilm but does not remove the smear layer - 17% EDTA does. Chlorhexidine 2% has substantivity but no tissue-dissolving ability, and it forms a precipitate with NaOCl, so flush between them with saline or EDTA. Calcium hydroxide is the standard inter-appointment medicament.
Obturation
Cold lateral or warm vertical compaction of gutta-percha with sealer; the master cone should show tug-back and reach working length. Warm vertical compaction gives a better three-dimensional fill in oval canals.
Worked example
A patient reports pain lasting two minutes after a cold test on a lower molar with a normal radiograph. Lingering pain indicates irreversible pulpitis, so pulpectomy and root canal treatment are correct; a sedative filling would be appropriate only if the pain had resolved within seconds.
Traps
- Sodium hypochlorite extrusion causes sudden pain, immediate swelling and ecchymosis - stop, irrigate with saline, allow drainage, give analgesia and review.
- Confusing a sinus tract (trace it with gutta-percha) with a periodontal pocket.
- A J-shaped radiolucency with a narrow deep pocket suggests vertical root fracture, not endodontic failure.
- Never force a file past the apical constriction.