Restorative Dentistry and Endodontics
Core concepts
Restorative questions test principles rather than brand names. Understand cavity design (resistance and retention form, extension for prevention), choice of material by location and load, and the adhesion hierarchy: enamel bonding is reliable, dentine bonding is moisture-sensitive and technique-dependent. Know the properties that drive selection - amalgam's compressive strength but poor aesthetics and mercury handling requirements; composite's aesthetics and enamel bond but polymerisation shrinkage and wear in high-load areas; glass ionomer's fluoride release and chemical bond to tooth but low fracture toughness.
Endodontics
Master the biological aim: eliminate infection and prevent recontamination. Learn working length determination (apex locator plus radiograph), canal preparation principles (patency, coronal flare, apical stop), irrigation (sodium hypochlorite dissolves tissue and is antimicrobial; EDTA removes smear layer; chlorhexidine is an alternative but must not be mixed with hypochlorite as a precipitate forms), and obturation. Recognise the classic complications: hypochlorite extrusion causing sudden severe pain and swelling, sodium hypochlorite accident management (stop, irrigate with saline, reassure, analgesia), instrument separation, and perforation.
Traps
- Assuming a radiolucency always means failure; healing can take 12-24 months and is judged clinically first.
- Confusing reversible and irreversible pulpitis: sharp, stimulus-provoked, resolving pain suggests reversible; spontaneous, lingering, nocturnal pain suggests irreversible.
- Forgetting rubber dam is a standard of care for root canal treatment.
Worked example
A patient reports severe lingering pain after a cold drink, lasting minutes, with no tenderness to percussion. Rule of thumb: lingering pain = irreversible pulpitis, so the answer is root canal treatment or extraction, not a sedative dressing and review. A sedative dressing belongs to reversible pulpitis, where pain resolves quickly once the stimulus is removed.