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The aFCR (adapted Flexicurve Ruler), with the spirit level parallel to the pre-drawn 30 cm horizontal line. The horizontal line is split into intervals of 5 cm (5 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm). The distance between horizontal line, at these marked intervals, and the trace of the sagittal profile was measured in millimetres.
