Oral Anatomy, Histology, and Physiology
Core concepts
Master tooth morphology by arch and type: permanent maxillary first molar (cusp of Carabelli, three roots, rhomboid outline), mandibular first molar (five cusps, two roots, mesial groove), and the distinguishing features of premolars and incisors. Know root canal numbers and shapes, the chronology of eruption (primary and permanent), and the histology of enamel, dentin, cementum, and pulp. Understand amelogenesis and dentinogenesis, the dentinoenamel junction, and the incremental lines (striae of Retzius, lines of Owen). Periodontal histology (gingival epithelium, junctional epithelium, principal fibers) and oral mucosa types (masticatory, lining, specialized) are frequently tested. Physiology includes saliva composition and flow, taste, mastication, and the physiology of the pulp-dentin complex.
Traps
Questions often swap primary and permanent tooth features, or confuse the number of roots/canals (e.g., mandibular first molar usually two roots but three canals). Eruption dates are commonly shifted by a year or two. Histology traps include confusing enamel (ameloblasts, no regeneration) with dentin (odontoblasts, continues forming). Be careful with the direction of enamel rod orientation and the location of the reduced enamel epithelium.
Worked example
Rule of thumb: "First molars are the largest and most variable; the maxillary first molar has the cusp of Carabelli and three roots, the mandibular first molar has five cusps and two roots." If a stem describes a rhomboid occlusal outline with an oblique ridge, the answer is the maxillary first molar.