A vital part of the patient’s orthodontic record is the images of the craniofacial area. The criterion that orthodontic records try to attain is the precise replication of the “anatomic truth”. The anatomic truth is defined as the accurate three-dimensional anatomy, static and in function, as it exists in vivo.
Imaging is one of the most common tools that orthodontists use to measure and record the size and form of craniofacial structures. Even though there are many image acquisition technologies currently available, the types of imaging used in clinics are decided based on the consideration of the anticipated benefits with associated costs and risks to patient. Because of these factors, orthodontists usually utilise two-dimensional static imaging techniques (e.g. periapical radiographs and photographs for teeth, homographs and magnetic resonance imaging for temporomandibular joints and cephalometric radiographs for the facial skeleton) to record the three dimensional anatomy of the craniofacial region. However, it segments anatomy by creating a patchwork of separate images to represent an entire structure. This parsing results in related anatomic structures being differentiated arbitrarily based on the point of view selected and the associated imaging geometry of that view. The segmenting of the anatomic structures places a difficult responsibility on the orthodontist to reconstruct the true anatomy mentally. Because of the limitations of this method, standardised analysis methodologies have been developed to describe the anatomic information contained in the images.
Although the use of imaging in orthodontics has been adequate throughout the years, the ideal goal to replicate the anatomic truth in image has been bounded by the technology available, database quality, and by legacy systems. Because of repetitive use, a legacy system becomes the status quo. Therefore, when a more accurate method comes, it is difficult to replace.
To make an accurate interactive multidimensional patient-specific model that represents craniofacial structures and tissues, multiple image sets of a patient would be entered into a common three-dimensional database. This “smart model” will be very helpful to the orthodontist as it would provide time-dependent, three dimensional location and interrelationships of its structural objects, like the jaws, TMJ disks, teeth, lips and other landmarks. This ideal imaging approach will give an accurate representation of the anatomic truth and more accuracy in the diagnosis and treatment plan of orthodontic patients.
