Hygiene Atlas

Atlas · Plate IX · Dental Radiography · 09

Normal radiographic anatomy

Radiolucent structures such as the pulp, PDL space, sinus and foramina appear dark; enamel, dentin, bone and metal appear light. Board items test landmarks by region: the incisive foramen and nasal fossa in the maxillary anterior, the sinus and zygomatic process in the posterior, and the genial tubercles, mental foramen and mandibular canal in the mandible.

High-yield facts · 7

  1. Radiolucent (dark): pulp, PDL space, sinus, nasal fossa, foramina, canals, air spaces. Radiopaque (light): enamel, dentin, bone, metal restorations.T7
  2. Maxillary anterior landmarks: incisive foramen (RL, between central roots), median palatine suture (RL line), nasal septum (RO), anterior nasal spine (RO V shape).T7
  3. Maxillary posterior landmarks: maxillary sinus (RL) and its septa, zygomatic process (RO "U" or "J"), maxillary tuberosity, hamulus, coronoid process of the mandible (RO triangle).T7
  4. The inverted "Y" is where the floor of the nasal cavity meets the anterior wall of the maxillary sinus, near the canine.T7
  5. Mandibular anterior landmarks: genial tubercles (RO ring) around the lingual foramen (RL dot), mental ridge (RO), mental fossa (RL).T7
  6. Mandibular posterior landmarks: mental foramen (RL, may mimic a periapical lesion of a premolar), mylohyoid ridge (RO), external and internal oblique ridges (RO), mandibular canal (RL band with RO borders), submandibular fossa (RL).T7
  7. Normal crestal bone sits about 1.5-2 mm below the CEJ, with a smooth, intact lamina dura.T7

Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.