15. Appendices
Green Smart User Manual 183
ENGLISH
Superior-Inferior (Up-Down) Positioning Error
Positioning the dental arches within the superior-inferior (up-down) dimension of the focal
trough can be difficult to achieve, especially with children whose smaller size reduces the
distance between the shoulders and the inferior border of the chin. When the arches are
positioned incorrectly in the superior-inferior direction, the image exhibits multiple
distortions, including increased overlapping in the premolar regions. When the arches are
positioned too far up or down, the teeth will simultaneously move into a position that is too
far back or too far forward, respectively, out of the focal trough.
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Positioning the arches too far superiorly produces a characteristic "frown" or flat,
downward- turned appearance to the occlusal plane (Figure 5). The condyles flare out
and off the edges of the image, and the palate appears as a widened, thick, dense
radiopacity. This positioning error results in a widened appearance of the palate and
obliterates the apical regions of the maxillary teeth, compromising the images of the
unerupted developing dentition. As the maxillary arch tips upward, the anterior teeth tilt
backward producing the same widened appearance that results from an incorrect anterior-
posterior position. Positioning the arches too far inferior produces a characteristic "smile"
appearance or upward curve of the occlusal plane, with the condyles tilting inward toward
the center of the image (Figure 6). Depending on the severity of the downward position,
the vertebrae may also curve inward and appear superimposed over the condyles, and
the hyoid bone may be superimposed over the mandible blocking a clear view of the
erupted and unerupted mandibular teeth.
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