Gamma CADIAX compact Series, Operating Instructions Manual

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Background information
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7 Background information
In this chapter you will find explanations regarding the terminology and backgrounds of the GAMMA
concept.
7.1 The reference coordinate system
In order to aggregate CADIAX condylography data and CADIAS cephalometry tracings, all GAMMA
products use the hinge-axis-orbital coordinate system as reference. This allows the reproducible and
standardized transfer of recorded data in the analog or virtual articulator.
The basis for the axis-orbital coordinate system is the
axis-orbital-plane (AOP), which is defined by the left and
right hinge axis points and the left orbital point (lowest
point of the orbit's anterior margin). Before a lateral ra-
diography, usually lead markers are placed on these
three points to indicate their location in the x-ray image.
The axis-orbital-plane on the cranium and in the articu-
lator. The visible axis point and the orbital point are
marked red.
The origin of the coordinate system is located centrally
on the hinge axis between right and left condyle. From
this origin, the positive X axis extends anterior towards
the orbital point, the positive Z axis downwards, and the
positive Y axis to the right, from the patient's point of
view. The median-sagittal plane coincides with the X and
Z axis, the transversal plane with the X and Y axis, and
the frontal plane with the Y and Z axis.
The origin of the axis-orbital coordinate system in the
articulator.