Figure 2. Measurements of periodontal parameters on the superimposed image. A–B: perpendicular line from the most coronal position of marginal gingiva to the long axis of the tooth; C–D: perpendicular line from the cementoenamel junction to the long axis of the tooth; E–F: parallel line with the C–D line positioned 4 mm apically from the C–D line; G–H: gingival thickness; H–I: alveolar bone thickness.