Biomedical and Behavioral Science Foundations
Microbiology and host response
Dental caries is a biofilm-driven, sugar-modulated disease; mutans streptococci and lactobacilli are associated with initiation and progression, but the ecological shift of the whole plaque community matters more than a single pathogen. Periodontitis involves a dysbiotic subgingival biofilm with organisms such as Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Treponema denticola, coupled with a destructive host inflammatory response. This explains why risk, not just plaque quantity, predicts disease.
Pharmacology you will be tested on
Local anesthetics are weak bases that cross the nerve membrane only in the uncharged form, then block sodium channels from inside in the charged form. Inflamed, acidic tissue shifts more drug to the charged form, so injection into infection fails - use a block or a different site. Remember interactions: metronidazole with alcohol, azoles and macrolides potentiating warfarin, NSAIDs raising bleeding and renal risk, and epinephrine effects in patients on nonselective beta blockers.
Behavior and development
Know the stages of change (precontemplation through maintenance) and how motivational interviewing differs from advice-giving: it elicits the patient's own reasons for change. Fear management uses tell-show-do, distraction, and gradual exposure. Craniofacial development questions often test pharyngeal arch derivatives, neural crest contributions, and the timing of anomalies - earlier insults produce more severe defects.
Traps
Attributing caries to sugar alone. Assuming a drug interaction is harmless because the patient has taken both before. Confusing operant with classical conditioning.
Rule of thumb: inflamed tissue is acidic, so an infiltration near an infection will underperform - anesthetize proximal to the source with a block. Worked example: a patient on warfarin with an INR in range who needs metronidazole should prompt a physician consultation, because the combination predictably raises INR and bleeding risk.