Dental Materials and Applied Basic Sciences (Anatomy, Physiology, Microbiology, Pharmacology)
What this domain tests
Dental materials and applied basic sciences test the chemistry and handling of materials, and the anatomy, physiology, microbiology, and pharmacology that underlie safe clinical decisions.
Core rules
- Composites polymerise with shrinkage; shrinkage stress rises with cavity configuration factor (C-factor) and poor bonding; place in increments in deep boxes.
- Glass ionomer bonds chemically to tooth, releases fluoride, and is moisture-sensitive while setting; resin-modified glass ionomer is less sensitive and is useful for margins and paediatric work.
- Amalgam has good compressive strength but can creep and corrode; avoid it in patients with impaired renal function only when there is a clear indication, not routinely.
- Ceramics: lithium disilicate is etchable and bondable; zirconia needs airborne-particle abrasion and a phosphate monomer.
- Addition silicone is dimensionally stable and hydrophobic; polyether is hydrophilic and rigid.
- Local anaesthetic maximum dose: lidocaine 4.4 mg/kg (absolute 300 mg), articaine 7 mg/kg, mepivacaine 6.6 mg/kg; epinephrine limit about 0.2 mg in cardiac patients.
- Antibiotic prophylaxis before dental procedures is limited to specific cardiac conditions, not prosthetic joints.
Worked example
A 60-kg patient needs 2% lidocaine with 1:100,000 epinephrine. Reasoning: 4.4 mg/kg x 60 kg = 264 mg; 2% = 20 mg/mL; 264/20 = 13.2 mL, about seven 1.8-mL cartridges, well above usual clinical need but the ceiling matters in children and in repeated injections.
Traps
Exceeding weight-based local anaesthetic limits; not aspirating; confusing the setting reaction of zinc phosphate with that of glass ionomer.