Pulp Therapy and Dental Trauma
What the exam tests
Pulp therapy questions test diagnosis first; trauma questions test the injury type, the tooth's maturity, and the time-critical step.
Core rules
- Pulpotomy: vital tooth, no radicular pathology, no swelling or sinus tract; agents include MTA, ferric sulfate 15.5%, and formocresol 1:5 for 5 minutes.
- Pulpectomy in primary teeth uses resorbable ZOE or iodoform paste, never gutta-percha.
- Direct pulp cap in primary teeth has a poor prognosis; indirect pulp cap is acceptable without irreversible signs.
- Avulsion: handle by the crown, store in milk, HBSS or saline, replant if within 60 minutes; flexible splint for 2 weeks; antibiotics and tetanus check; closed apex needs RCT at 7-10 days; open apex needs revascularization.
- Intrusion: a primary tooth may be left to re-erupt unless it threatens the permanent bud; a permanent tooth with a closed apex often needs orthodontic extrusion or RCT.
- Splint duration: luxation 2 weeks, root fracture 4 weeks (cervical 4 months), avulsion 2 weeks.
Worked example
A 9-year-old falls and the maxillary central incisor is avulsed and dry for 45 minutes. Reasoning: closed apex, extraoral time under 60 minutes, so replant after gentle saline rinse, flexible splint for 2 weeks, systemic antibiotics, tetanus check, and RCT at 7-10 days because revascularization is unlikely.
Traps
Replanting a primary tooth; scrubbing the root; rigid splinting for 6 weeks; delaying RCT in a closed-apex avulsion; missing a root fracture on a single radiograph.