Operative Dentistry and Endodontics
What this domain tests
This domain tests caries management, cavity preparation, adhesive dentistry, pulp diagnosis, root canal treatment, and dental trauma. Questions often ask for the next clinical step or the reason a technique fails.
Core rules and concepts
- Caries is a dynamic demineralization and remineralization process. Fluoride, plaque control, and dietary change shift the balance toward remineralization; cavitation requires restoration.
- Resistance and retention form differ. Amalgam needs mechanical retention; composites rely on enamel and dentin bonding. Enamel margins and moisture control strongly affect composite longevity.
- Pulp diagnosis uses history, cold test, electric pulp test, percussion, palpation, and radiographs. Lingering cold pain suggests irreversible pulpitis; a necrotic pulp may not respond to cold or EPT.
- Endodontic access should be straight-line to canal orifices. Working length is confirmed with an apex locator and radiograph. Sodium hypochlorite dissolves tissue and disinfects; EDTA removes smear layer; do not mix sodium hypochlorite and chlorhexidine because a precipitate can form.
- Obturation requires a three-dimensional fill and a coronal seal. Gutta-percha with sealer is standard.
- Avulsed permanent teeth should be replanted promptly, stored in milk or balanced salt solution, and splinted; do not scrub the root.
Worked example
A mature tooth has deep caries, lingering cold pain, and no periapical radiolucency. The reasoning is irreversible pulpitis. Root canal treatment is indicated; a sedative filling alone is unlikely to resolve spontaneous or lingering pain. If the tooth were immature, apexogenesis or pulpotomy might be considered to preserve root development.
Traps that cost marks
Do not diagnose pulp necrosis from a single cold test. Do not overinstrument curved canals. Never mix sodium hypochlorite and chlorhexidine. Do not scrub an avulsed tooth or delay replantation unnecessarily. Also remember that a coronal seal matters as much as the obturation itself.