Background- Frankfort horizontal line and sella- nasion lines are the most widely accepted landmarks in cephalometric analysis. This study investigates the use of the orbito-condylion line extending from the orbitale to the condylion as a novel horizontal line of the skull for substituting the Frankfort horizontal line. Similarly, the evaluation of the orbito-basion line as an alternative to sella- nasion line in cephalometric analysis, is done.
Methods- This investigation is carried out as study on 30 individuals. The porion, orbitale, condylion, sella, nasion, and basion were identified and indicated. The angles between the orbito-meatal line (inferior orbital rim to porion; the Frankfort line) and the orbito-condylion line (inferior orbital rim to condylion) were measured. Likewise, the angles between the sella- nasion line (centre of sella tursica to nasion) and the orbito-basion line (inferior orbital rim to basion) were measured.
Results-There was no significant interobserver and intraobserver bias. The overall angle between the Frankfort line and orbito-condylion line was 0.5°±2.27° (mean±standard deviation) and the angle between the sella nasion line and orbito-basion line was 3.48°±3.11°.
Conclusion-This study demonstrated good reproducibility, reliability and good efficacy of the new lines. The orbito-condylion and orbito- basion lines are reliable, reproducible, and easily identifiable lines, and has potential as novel standard horizontal lines to replace or at least supplement the Frankfort line and sella- nasion lines in anthropological studies and clinical applications.