Operative/Restorative Dentistry
Operative dentistry: preserve tooth structure, control the field
Operative questions test principles more than brand names. Understand caries as a biofilm-driven disease: restore cavitation, but also address risk with fluoride, diet, and hygiene. Minimally invasive preparation removes infected and unsupported tissue while preserving sound enamel and dentin. Know the difference between enamel and dentin bonding: enamel is highly mineralized and benefits from phosphoric acid etching; dentin is wet, tubular, and requires primer and adhesive. Total-etch and self-etch systems handle moisture differently.
For direct restoratives, compare amalgam and composite honestly. Amalgam is strong, moisture-tolerant, and durable but nonesthetic; composite bonds, conserves tooth structure, and is esthetic but technique-sensitive and polymerizes with shrinkage. Shrinkage stress rises with cavity configuration (C-factor), so place composite in increments no thicker than about 2 mm and cure from the direction that reaches the material. Use a matrix and wedge to restore proximal contour and contact. Rubber dam isolation improves visibility and moisture control, especially for adhesive work.
Traps: assuming every radiolucency needs drilling; using composite in a field contaminated by blood or saliva; forgetting that dentin etching is shorter than enamel etching; and ignoring occlusion after a large restoration. A high spot can cause sensitivity, fracture, or periodontal symptoms.
Rule of thumb: if you cannot keep the field dry, choose a material that tolerates moisture or improve isolation before bonding. Example: a cervical class V lesion near the gingival margin often needs retraction cord, hemostasis, and a self-etch or selective-etch approach rather than a rushed total-etch bond.