Roentgenology

• Bitewing radiography

  Interproximal radiographs that include crowns of the maxillary and mandibular teeth, and the alveolar crest, on the same receptor
• Bitewing radiography

  • Long axis usually oriented horizontally
  • Beam directed through the interproximal spaces and parallel with the occlusal plane
  • Receptor placed parallel to the buccal and lingual surfaces of teeth being examined; perpendicular to x-ray beam
• Patient positioning for bitewing radiography

  • Seated upright in the dental chair
  • Sagittal plane is vertical, occlusal plane is horizontal
• Horizontal bitewing receptor placement

  1. Parallel to the buccal surfaces of the teeth being radiographed

  2. Have the patient bite gently on the bite block

  3. Mandibular canine used as guide for premolar bitewing receptor placement

  4. Molar receptor placed 1-2 mm beyond the most distally erupted molar
• Vertical bitewing receptor placement

  1. Used when patient has moderate-severe alveolar bone loss

  2. Same principles for positioning the receptor and orienting the X-ray beam as for horizontal projections
• Tube head angulation

  • Horizontal: X-ray beam directed through the contacts
  • Vertical: aiming cylinder positioned about +10 degrees
• Premolar bitewing image field

  • Should include the distal portion of the mandibular canine anteriorly and show equally the crowns of the maxillary and mandibular premolar teeth
• Premolar bitewing receptor placement


  1. Between the tongue and teeth

  2. Parallel to the long axis of the tooth
• Premolar bitewing central ray projection

  1. To the center of the receptor through the premolar contact areas

  2. Vertical angulation should be about +5 degrees
• Molar bitewing image field

  • Should show the distal surface of the most posterior erupted molar and equally the crowns of the maxillary and mandibular molars
• Occlusal radiography

  • Used to localize objects and pathologic conditions in the buccolingual dimension
  • To visualize areas that would not be seen on periapical and bitewing projections because of insufficient field size
• Right-angle occlusal projection

  1. 90-degree/cross-sectional projection

  2. Central ray directed at 90 degrees to the receptor
• Topographic occlusal projection

  1. Angulation varies from 35-75 degrees

  2. Extreme vertical angulations necessary to compensate for the lack of parallelism between the object and the receptor
• Occlusal receptor

  • Size #4 (2.5 x 3 inch)
  • Single- or double-packet films
  • Various speeds
  • #2 size receptor can be used for pediatric projections
  • Processing of these film packets is the same as for other intraoral films
  • Exposure time setting is equivalent to that used for the maxillary molar periapical projection
• Mandibular occlusal technique

  1. Receptor placed on the occlusal surfaces of the lower teeth

  2. White side of the packet should face the mandible on the occlusal surfaces of the lower teeth

  3. Film placed horizontally and as far posterior on the mandible, as possible

  4. Direct the patient to bite gently on the receptor

  5. Central ray directed from under the mandible

  6. Back of the chair is lowered, patient's chin is tilted up

  7. Topographic: central ray directed at a point just above the mental eminence at a vertical angulation of 35-45 degrees
• Maxillary occlusal technique


  1. Topographic: receptor placed in the patient's mouth on the occlusal surfaces of the maxillary teeth

  2. Front of the film packet facing the palate and the long dimension of the packet running across the mouth

  3. Positioned as far as possible so that the posterior edge of the film packet touches the ascending ramus of the mandible

  4. Position the patient's head so that the receptor plane is parallel to the floor

  5. Direct the central ray at a 65-75 degree vertical angulation aimed at the bridge of the nose

  6. Right-angle: same position as topographic projection, but central ray is directed perpendicular to the center of the film packet

  7. PID positioned above the patient's head at about the hairline

  8. Vertical angulation: 90 degrees

  9. Posterior topographic view can be considered a view of the maxillary sinus and surrounding structures

  10. Receptor positioned on the left/ right side of the patient's mouth, from the midline, laterally with the long side running anteroposteriorly

  11. Central ray directed to a point just above the apices of the premolars

  12. Vertical angulation approximately 65 degrees