Restorative Dentistry and Endodontics
Restorative Dentistry and Endodontics tests conservative preparation, adhesion, pulp protection, endodontic diagnosis, cleaning and shaping, obturation and restoration of treated teeth.
Core concepts
- Cavity design removes infected and unsupported tissue while preserving sound enamel and dentin. Bevels increase enamel bond area but are not universal.
- Etch-and-rinse: phosphoric acid removes the smear layer, then primer and adhesive are applied. Self-etch: an acidic primer simultaneously etches and primes; it is less technique-sensitive but weaker on uncut enamel.
- Composite shrinkage creates stress at bonded interfaces. C-factor is the bonded-to-unbonded surface ratio; incremental placement, soft-start curing and liners reduce stress.
- Pulp diagnosis: reversible pulpitis is provoked and brief; irreversible pulpitis is spontaneous or lingering; apical periodontitis shows percussion sensitivity and often a periapical radiolucency.
- Working length is typically 0.5–1.0 mm short of the radiographic apex.
- Sodium hypochlorite dissolves organic tissue; EDTA removes the smear layer; chlorhexidine has substantivity. Sodium hypochlorite and chlorhexidine form a precipitate and should not be mixed.
Worked example
A molar has lingering cold pain and no periapical radiolucency. Diagnosis: irreversible pulpitis. Reasoning: a lingering response means the inflammation cannot resolve; treatment is pulpectomy or extraction, not a sedative filling alone.
Traps
Do not rely on a single radiograph for working length. Do not use sodium hypochlorite without isolation. Do not attempt to remove a separated instrument without magnification and a plan. Do not restore a cracked tooth without assessing crack depth.