Cephalometry In Orthodontics: 2D And 3D

Cephalometry In Orthodontics: 2D And 3D

• Except for a few structures of interest which lie in the midsagittl plane it is diffilt to make accurate measurements using 2D cephalograms. Conventional facial photos too lose depth information by projecting images of structures at diffrent heights upon a single plane. Also the one true 3D representation of oral tissues, the dental cast must be integrated into facial images.
• In the late 1970s computerized axial tomography initially referred to as CAT and later CT become available. CT measures X-ray attnuation coeffients as they spatially vary across a section of the anatomy. They are ideal for the visualization of hard osseous structures as these structures attnuate X-rays more than the surrounding sof tissues.
• Upon introduction it was heralded that the CT and the MRI would replace conventional radiography. However, their use in conventional orthodontic treatment has been limited due to the following reasons:

“Importance of studying 2D and 3D cephalometry for better outcomes”

• • The dose of ionizing radiation has been high.
  • Economic costs are prohibitive.
  • Slices of relatively thick tissue detail in vertically oriented teeth is quite poor.
• Distortions are produced if CT scans are done with orthodontic appliances in place.
• All 3D imaging systems try to capture the Z-axis and this they achieve by counting the number of slices into which the images are divided.
• Calibration is particularly important when one tries to integrate 3D images and the 2D cephalogram.
• The problem with 3D imaging of face is that the face inherently contains litte detail and it is diffilt to obtain a set of discrete points which can then be used to superimpose and to construct a useful map.

“Steps to explain 2D and 3D cephalometric analysis in orthodontics”

• 3D cephalometric planning is ideal for orthognathic cases where the outcome can be visualized or simulated and executed on patient approval, it has yet to be implemented for routine use in orthodontics particularly when we have limitation like radiation dose.
• The CBCT is ideal tool for 3D diagnosis and treatment planning. We have to train ourselves towards concepts of 3D.
• But still these days practitioners may be talking about 3D and still tend to put 2D landmarks on skull as for years they are trained in 2D landmarks for teeth and jaws.
• 3D cephalometric analysis may be routinely used for 3D assessment of all orthodontic cases in the near future and become an essential part of treatment planning.