Cariology and Restorative Dentistry (Operative Dentistry)
What the exam tests
Caries detection and risk-based prevention, minimal-intervention cavity design, and the material science behind a restoration that seals and lasts.
Core rules
- Diagnose before you drill: ICDAS scores 0-6 separate initial lesions from cavitation. White-spot lesions on smooth surfaces are reversible with fluoride varnish, plaque control and dietary change.
- Caries management is risk-based: recall interval and preventive intensity follow caries risk, not a fixed six-month rule.
- Enamel bonding relies on acid etching creating microporosity; dentin bonding must additionally handle the smear layer and its water content. Total-etch removes the smear layer; self-etch modifies it.
- Over-drying etched dentin collapses the collagen mesh and reduces bond strength; ethanol wet bonding and gentle air drying preserve it.
- Polymerisation shrinkage is highest under a high C-factor (confined cavity). Place composite in increments no thicker than 2 mm, use a flowable liner or bulk-fill base, and cure from more than one direction.
- Rubber dam isolation, a matrix and wedge (for proximal contacts) and careful contouring are part of the procedure, not extras. Cusps weakened by undermining should be covered.
Worked example
A 46-year-old has a deep occlusal lesion with softened dentin close to the pulp, no spontaneous pain, and a normal cold response. Reasoning: this is active dentin caries at risk of pulp exposure. Remove peripheral infected dentin, leave leathery affected dentin over the pulp (selective removal to soft dentin), seal with a resin-modified glass ionomer or adhesive and restore with composite. Re-entry is not needed if the tooth stays asymptomatic.
Traps that cost marks
- Etching dentin for the same time as enamel, then overdrying it.
- Restoring a 4 mm deep cavity with a single composite increment.
- Choosing amalgam or composite by habit rather than by moisture control, cavity extent and patient factors.