Standard Diagnostic Tools in Orthodontics

10.1055/b-0034-75525

Standard Diagnostic Tools in Orthodontics

Standard orthodontic records may consist of study models, radiographs (orthopantomogram and lateral cephalo-gram, where indicated), as well as photographic records. Most of these records are regarded as an orthodontic standard, as they are usually required for comprehensive diagnosis and treatment planning. Although intraoral photographic documentation is not compulsory in many countries, we find that it is often very helpful; magnification of photographic records may highlight issues that are difficult to detect in a visual intraoral examination or from analysis of the study models. It is often an examination of photographic records that highlights clinical issues (such as bracket positioning or achievement of three-dimensional tooth movements) that are not observed during routine clinical examinations.

NOTE

Further diagnostic imaging may involve additional radiographs, such as:

  • Periapical, upper and/or lower standard occlusal radiographs

  • Posteroanterior cephalometric analyses (PA cephs)

  • Cone beam computed tomography (CBCT)

  • Magnetic resonance imaging (MRI)

Cone-beam tomograms or dental CTs provide good modeling of the three-dimensional structure for analysis and exact positioning of the teeth ( Fig. 4.1 ). They can also be used for three-dimensional reconstructions of the facial skeleton ( Fig. 4.2 ). However, it is important to remember that radiation protection is paramount, and it is often possible to ascertain the exact positioning of teeth using clinical observations and/or conventional radiographs on two different spatial planes.1 , 5 , 6 , 7 , 8 MRI scanning in orthodontics is rare, but can be particularly useful in cases where conventional x-ray imaging fails, such as detailed imaging of soft-tissue structures. The present authors use magnetic resonance imaging (MRI) as an additional technique for precise diagnosis of temporomandibular joint disorders and occasionally for presurgical assessment and planning of potential treatments, particularly lower jaw surgery ( Fig. 4.3 ). Occasionally, interdisciplinary care may be necessary for patients affected by periodontal disease, for example. Further diagnosis of preexisting diseases or conditions may also be indicated. Other developments in optical three-dimensional imaging techniques can also be expected, such as FaceScan 3D (GF Messtechnik Ltd., Berlin, Germany, 3D-Shape Ltd., Erlangen, Germany), which do not expose the patient to ionising radiation and allow three-dimensional digital data analysis of the patient’s profile and soft tissues ( Fig. 4.4 ).

Fig. 4.1a–d Dental cone-beam computed tomography (CBCT) with three-dimensional reconstruction for diagnostic purposes. a, b A displaced tooth 11. c, d Impacted canines.
Fig. 4.2a, b Reconstruction of the posterior airway.
Fig. 4.3a–f Three-dimensional reconstruction of magnetic resonance images for improved visualization of articular disk displacement. The raw scan (a, b) was modified using Amira 4.0 (Mercury Computer Systems) to focus on the condyle (c, d) as well as allowing visualization of the articular disk and the surrounding muscles (e, f). The conventional tomographic images remain readily available for comparative purposes.2 4 The images were kindly provided by Prof. Kober and Prof. Kinzinger.
Fig. 4.4a, b Three-dimensional reconstruction of the facial soft tissues after optical scanning of the facial contours (FaceScan 3D).
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Jul 7, 2020 | Posted by in Orthodontics | Comments Off on Standard Diagnostic Tools in Orthodontics
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