Table 1 Cephalometric landmarks, measurements and reference lines used in the study
Landmarks/Measurements/ Reference lines | Abbreviation | Descriptions |
|---|---|---|
Sella | S | Centre the sella turcica |
Nasion | N | The most receding point of the anterior surface of the frontonasal suture |
Rhinion | R | The most prominent and inferior point on the nasal bone |
Apex of incisor | Ia | Apex of maxillary central incisor |
Incision superius | Is | Incisal edge of the most protruded maxillary central incisor |
True vertical reference line | TrH | A line was traced overlapping the plumb line on the lateral cephalometric radiographs |
Sella vertical reference line | STrH | A line was drawn through the Sella point parallel to the TrH |
Distance from incision superius to STrH | U1-S-STrH (D) | The horizontal distance between the vertical line tangent to the incision superius and the STrH. |
Distance from the rhinion to STrH | N-R-STrH (D) | The horizontal distance between the vertical line tangent to the rhinion and the STrH. |
Distance from the apex of incisor to STrH | U1-A-STrH (D) | The horizontal distance between the vertical line tangent to the apex of maxillary central incisors and the STrH. |
Distance from nasion to STrH | N–N-STrH (D) | The horizontal distance between the vertical line tangent to the nasion and the STrH. |
Angle of nasal bone and SN | ∠ N-SN | The angle between the axis of the nasal bone (the line from the rhinion point to the midpoint of the base of the nasal bone) and the SN line. |
Angle of incisor and SN | ∠ U1-SN | The angle between the axis of the maxillary central incisor and the SN line. |
SN-7° line | SN-7° | A line drawn with 7° down from the SN line. |
Angle of nasal bone and SN-7° | ∠ N-SN-7° | The angle between the axis of the nasal bone and the SN-7° line. |
Angle of incisor and SN-7° | ∠ U1-SN-7° | The angle between the axis of maxillary central incisor and the SN-7°line. |
Length of the incisor | U1 (L) | The length from maxillary central incisor, from incisal edge to its apical point of the root. |
Length of nasal bone | N (L) | The length from the anterior point of the nasal bone to the midpoint of the base of the nasal bone. |
Ratio of angles | A (r) | Angle of nasal bone and SN / Angle of maxillary central incisor and the SN line. |
Ratio of angle- SN-7° | A (7°) (r) | Angle of nasal bone and SN-7°/ Angle of maxillary central incisor and the SN-7° line. |
Ratio of distance | D (r) | Distance from the tip of the nasal bone to the STrH / Distance from incision superius to the STrH line. |
Ratio of length | L (r) | Length of nasal bone / Length of maxillary central incisor. |