Lateral Cephalogram Requirements

 

1. Conform to requirements discussed under Overall Requirements for Radiographs.

2. Lateral cephalograms must show as much anatomy as possible, especially in vital landmark areas, for each level of evaluation.

3. The soft tissue profile should be visible on lateral cephalograms.

4. Posterior-Anterior (PA) or sub-mental vertex cephalograms should be included in the case presentation when diagnostically appropriate.

5. All records should be properly standardized, oriented and processed.

6. If presentation is by electronic case submission (ECS):

The lateral cephalogram must have a calibration mechanism (e.g. a ruler, wire, or image of specified length) visible on the image.

This is essential to prepare the cephalometric tracing. A calibration ruler of 100mm is typical for scanned images, and most direct digital x-ray systems include a scale somewhere in the system. Alternatively, a 100mm length of wire can be affixed to the cephalometric head stabilizer so that it appears in the image and yet does not interfere with the anatomy.

ABO Policy Statement Regarding Lateral Cephalometric Radiographs and Superimposition of Tracings

With the advent of three dimensional technologies, the inherent inaccuracies of traditional radiographs have come into question. While no person has ever believed that cephalometric data collection was an exact science, orthodontics has continuously placed a high degree of importance on superimpositions as an accurate way of:

1. Determining changes in growth and development and treatment.
2. Ascertaining the amount and direction of tooth movement.

Three dimensional volumetric assessments produce exact measurements.1. 2.  When this type of data is compared to traditional cephalometric information (analogue and digital technology), indiscriminant errors in the actual location of vital landmarks necessary to establish superimpositions are found.


In spite of this problem, the Board encourages the continued use of "like" cephalograms (i.e. cephalograms produced on the same machine), and expects examinees to produce high quality cephalometric radiographs using the ABO measurements to determine diagnostic approaches for patient care and to reveal the final treatment results. Use of these accurately traced cephalograms will give the examinee very valuable information about tooth movement, amount and direction of growth, or lack thereof.


While the Board recognizes that magnification errors will always be present unless three dimensional volumetric radiographs are utilized, it does not dismiss the examinee's responsibility to:

A. inform the Board the conditions under which the initial, progress, and final cephalometric radiographs were obtained.
B. create radiographic superimpositions demonstrating the highest degree of accuracy possible.

 

When the examinee indicates that pre and post-treatment lateral cephalograms were not taken on the same machine:

  • Cephalometric tracings are still required, but superimposition(s) are not required.
  • The examinee must explain the reason for the absence of superimposition(s)..
  • The examinee must be able to explain the changes that occurred during the treatment of their patient.
  • The examinee will be sent a board case(s) with pre- and post-treatment cephalograms which require tracings and superimpositions to be presented with their case reports. Interpretation of the board cephalograms should not be included in the written case report.
  • Notate this with a checkmark in the appropriate box of the Written Case Report, Results Achieved section.
  • You are representing that the lateral cephalograms were not exposed on the same machine and disproportionate magnification occurred. In this situation, superimpositions are preferred but are not required.
  • You are responsible for knowing and explaining the superimposition requirements and the changes that occurred as a result of treatment and growth.
  • ABO Policy Statement Regarding Lateral Cephalometric Radiographs and Superimposition of Tracings 

1.  Adams GL, Miller AJ, Harrell Jr. WE, and Hatcher DC. Comparison between traditional 2-dimensional cephalometry and a 3-dimensional approach on human dry skulls. Am J Orthod Dentofacial Orthop 2004; 126:397-409
2.  Harrell WE, Jr., Hatcher DC, Bolt RL. In search of anatomic truth: 3-dimensional digital modeling and the future of orthodontics. Am J Orthod Dentofacial Orthop 2002; 122:325-330.