Operative Dentistry and Direct Restorations
Operative Dentistry and Direct Restorations tests whether you can remove caries and restore contour, contact and occlusion without destroying sound tissue or creating sensitivity. Questions emphasise adhesion, isolation, matrix techniques, deep-lesion management and material selection.
Core rules
- Remove peripheral caries to sound enamel at the cavosurface, but in deep lesions use selective removal to soft dentine or stepwise excavation to reduce pulp exposure; leave no soft caries at the margin.
- Rubber dam is the standard for adhesive and endodontic work; saliva contamination of etched dentine sharply reduces bond strength.
- Etch-and-rinse: 30 s enamel, 15 s dentine, rinse, then leave dentine visibly moist. Self-etch does not require rinsing, but its enamel bond is weaker, so many clinicians selectively etch enamel margins.
- Keep increments to 2 mm or less, or use a bulk-fill material within its validated depth (often 4 mm) to limit shrinkage stress and ensure cure.
- Restore contacts with a sectional matrix and ring; check occlusion in maximum intercuspation and in excursions.
Worked example
Tooth 46 has a deep occlusal lesion with no spontaneous pain, normal cold response and no percussion tenderness. Diagnosis is active dentinal caries with reversible pulpitis. Plan: rubber dam, caries removal with slow-speed and hand excavators, selective removal over the pulp, a calcium hydroxide or resin-modified glass ionomer base only if needed, adhesive composite in increments, sectional matrix, occlusal check, and a warning about transient post-operative sensitivity.
Traps
- Cavosurface margins left in caries, causing early marginal failure.
- Failing to verify occlusion in lateral excursions, producing a heavy contact and fracture.
- Using composite where moisture cannot be controlled instead of a glass ionomer or a different sequencing.