Figure 1.

Schematic diagram of 3D measurement method. (A) A three-dimensional model constructed from micro-CT data showing selected landmarks: the centre of each canal orifice (O) at the level of cemento enamel-junction (CEJ), the centre of the canal primary curve (PC) in the maximum curvature view and the intersection point of the middle axis of the coronal part of the root canal and the occlusal surface (IO). (B) View from the occlusal aspect of a mandibular first molar with a 32 × 32-grid (C) Three-dimensional model of CBCT data showing the determination of the maximum angle of curvature in the maximum coronal root canal curvature in the axial direction.