GENDEX Oralix AC Manuel De L'utilisateur page 12

GENDEX
Rotate the tubehead in its trunnion, by holding the cone and the handgrip, to proper angle
depending on the radiograph to be made. The tubehead angle can be read on the graduated
scale on the side of the tubehead.
Please note that the tubehead can be rotated continuously around the horizontal axis (the
vertical pivoting shaft), and for 270° vertically (around the horizontal axis of the trunnion).
Make sure that you are using the proper (that is middle) part of the 270° range.
Position the film into the patient's mouth in the proper position, either by using a holder or a by
free hand (in the latter case the film must be hold in position by the patient's index finger, not
the operator's!).
Paralleling Technique
Paralleling technique produces the most accurate image of the teeth as it follows the principles of accurate shadow
casting (more closely than the bisecting technique does). An accurate shadow casting is obtained when the long
axis of the tooth is placed parallel to the film. The undesirable enlargement of the object can be avoided by using a
"parallel" x-ray beam. With the Oralix AC an SSD of 20 cm is used. At this distance, conditions are suitable for
applying the paralleling technique. In order to escape the restrictions of the oral anatomy, the film must be
positioned further away from the tooth. The radiographic enlargement will be approx. 15%. In order to place the
film parallel to the tooth axis, film holders can be used.
The Oralix AC is thus positioned in relation to the film holder. As a consequence of the technique applied, a
smaller tubehead angle is used than with the bisecting technique.
Bisecting Technique
With the bisecting technique, the radiographic enlargement is selected so that of the tooth axis equals the length
on the radiograph. This is obtained by placing the central ray perpendicular to the bisector of tooth axis and film.
The radiographic enlargement due to the different film-object distance along the length of the tooth is acceptable.
Grab the tubehead from behind, and move it close to the patient's head. Direct the tubehead
and gently bring it to the patient's head until the cone tip touches the patient skin at the area
to be examined. Finally check the angle again.
Please note that, in order to ensure the required mechanical stability, the folding arm needs to
be open at least 10°. Smaller angles may cause the arm to drift to zero, i.e. completely folded,
thus impairing stability and position of the x-ray source.
Make an exposure by keeping the exposure handswitch firmly pressed.
During an exposure all personnel must stay away from path of the primary x-ray beam, preferably behind
the tubehead and at least 2.5 m from the patient's head, in order to ensure that the potential exposure to
direct and scattered radiation be less than the limit indicated in the applicable international standards.
The value of a radiograph depends not only on the amount of details it reveals but also on the
accuracy with which the film and object have been positioned, in relation to the x-ray beam.
Therefore, the use of positioning devices is encouraged, in order to properly position and
align the detector in relation with the radiographic object (e.g. the tooth to be radio graphed)
and the cone.
8 Oralix AC
Printed on: 22 Mär 2012, 09:22:12 am; Printed by: TOBIAS BAUER