Hygiene Atlas

Atlas · Plate IX · Dental Radiography · 06

Intraoral technique

The paralleling technique places the receptor parallel to the tooth's long axis with the central ray perpendicular to both, giving the most accurate image. The bisecting technique aims at the line that bisects the tooth and receptor and distorts more. Bitewings use about +5 to +10 degrees of vertical angulation, and the buccal object rule (SLOB) locates objects buccolingually.

High-yield facts · 11

  1. Paralleling technique: receptor parallel to the long axis of the tooth, central ray perpendicular to both; uses a long (16 in) or 12 in PID and a holder. It gives the most accurate image.T7
  2. Bisecting angle technique: central ray perpendicular to the imaginary line bisecting the angle between the tooth's long axis and the receptor; more distortion.T7
  3. Bisecting vertical angles (approx.): maxillary incisors +40 to +50, canines +45 to +55, premolars +30 to +40, molars +20 to +30 degrees.T7
  4. Bisecting vertical angles (approx.): mandibular incisors -15 to -25, canines -20 to -30, premolars -10 to -15, molars -5 to 0 degrees.T7
  5. Bitewings use about +5 to +10 degrees vertical angulation; horizontal angulation goes through the contacts.T7
  6. A standard adult FMX usually has about 18-20 images (for example 14-16 periapicals plus 4 bitewings).T7
  7. Vertical bitewings are used to show more crestal bone in periodontal patients.T7
  8. Buccal object rule (SLOB): when the tube shifts, a lingual object moves the Same way; a buccal object moves Opposite.T7
  9. Image sharpness improves with a smaller focal spot, a longer source-object distance and a shorter object-receptor distance.T7
  10. Occlusal images: maxillary topographic at about +65 degrees; mandibular cross-sectional with the beam at 90 degrees to the receptor.T7
  11. Gag reflex control: work quickly, place receptors posteriorly last, have the patient breathe through the nose, and use topical anesthetic if needed.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.