Fig. 1From: Influence of Invisalign treatment with interproximal enamel reduction (IER) on bone volume for adult crowding: a retrospective three-dimensional cone beam computed tomography studya+b Two-dimensional illustration of the maxillary and mandibular reference plane. a Two-dimensional illustration of the maxillary reference plane, with the reference points “Emartrechts” and “Nasion” and the parallel measurement planes at the level of the apex and center of the root, for tooth 11. b Two-dimensional illustration of the mandibular reference plane, with the reference points “MandPlre” and “MandPlvorne” and the measurement planes at the level of the apex and center of the root, for tooth 41Back to article page