Panoramic radiograph
Panoramic radiograph | |
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temporomandibular joint and other near by head and neck anatomy. | |
MeSH | D011862 |
A panoramic radiograph is a
are in the focal trough and the structures that are superficial and deep to the trough are blurred.Other nonproprietary names for a panoramic radiograph are dental panoramic radiograph and pantomogram; Abbreviations include PAN, DPR, OPT, and OPG (the latter, based on genericizing a trade name, are often avoided in medical editing).
Types
Dental
The manufacturers propose different solutions for moving the arm, trying to maintain constant distance between the teeth to the film and generator. Also those moving solutions try to project the teeth
Films
There are two kinds of film moving mechanisms, one using a sliding flat cassette which holds the film, and another using a rotating cylinder around which the film is wound. There are two standard sizes for dental panoramic films: 30 cm × 12 cm (12″ × 5″) and 30 cm x 15 cm (12″ × 6″). The smaller size film receives 8% less X-ray dosage on it compared to the bigger size.
Digital
Dental X-rays' radiology is moving from film technology (involving a chemical developing process) to
One particular type of digital system uses a
Also sometimes the term "digital X-rays" is used to designate the scanned film documents which further are handled by computers.
The other types of digital imaging technologies use electronic sensors. A majority of them first convert the X-rays in light (using a GdO2S or CsI layer) which is further captured using a CCD or a CMOS image sensor. Few of them use a hybrid analog-to-digital arrangement which first converts the X-ray into electricity (using a CdTe layer) and then this electricity is rendered as an image by a reading section based on CMOS technology.
In current state-of-the-art digital systems, the image quality is vastly superior to conventional film-based systems. The latest advancements have also seen the addition on Cone Beam 3D Technology to standard digital panoramic devices.
Indications
Orthopantomograms (OPTs) are used by health care professionals to provide information on:
- Impacted wisdom teethdiagnosis and treatment planning - the most common use is to determine the status of wisdom teeth and trauma to the jaws.
- Periodontal boneloss and periapical involvement.
- Finding the source of dental pain, and when carrying out tooth-by-tooth diagnosis.
- Assessment for the placement of dental implants
- Orthodonticassessment. pre and post operative
- Diagnosis of developmental anomalies such as cleido cranial dysplasia
- Carcinoma in relation to the jaws
- Temporomandibular joint dysfunctions and ankylosis.
- Diagnosis of osteosarcoma, ameloblastoma, renal osteodystrophy affecting jaws and hypophosphatemia.
- Diagnosis, and pre- and post-surgical assessment of maxillofacial trauma, e.g. dentoalveolar fractures and mandibular fractures.
- Salivary stones (Sialolithiasis).
- Other diagnostic and treatment applications.[2]
Mechanism
Normally, the person bites on a plastic spatula so that all the teeth, especially the crowns, can be viewed individually. The whole orthopantomogram process takes about one minute. The patient's actual radiation exposure time varies between 5.5 and 22 seconds for the machine's excursion around the skull.
The
The dental panoramic image suffers from important distortions because a vertical zoom and a horizontal zoom both vary differently along the image. The vertical and horizontal zooms are determined by the relative position of the recorded element versus film and generator. Features closer to the generator receive more vertical zoom. The horizontal zoom is also dependent on the relative position of the element to the focal path. Features inside the focal path arch receive more horizontal zoom and are blurred; features outside receive less horizontal zoom and are blurred.
The result is an image showing sharply the section along the mandible arch, and blurred elsewhere. For example, the more radio-opaque anatomical region, the cervical vertebrae (neck), shows as a wide and blurred vertical pillar overlapping the front teeth. The path where the anatomical elements are recorded sharply is called "focal path".
Principal advantage of panoramic images
- Broad coverage of facial bone and teeth
- Low patient radiation dose
- Convenience of examination for the patient (films need not be placed inside the mouth)
- Ability to be used in patients who cannot open the mouth or when the opening is restricted e.g.: due to trismus
- Short time required for making the image
- Patient's ready understandability of panoramic films, making them a useful visual aid in patient education and case presentation.
- Easy to store compared to the large set of intra oral x-rays which are typically used.[3]
Preparation
Persons who are to undergo panoramic radiography usually are required to remove any earrings, jewellery, hair pins, glasses,
Adverse effects
Like any medical imaging utilizing
History
Historical milestones for digital panoramic systems
1985–1991 – The first attempt to build a dental digital panoramic was of McDavid et al. at
1995 – DXIS, the first dental digital panoramic X-rays system available on the market, created by Catalin Stoichita at Signet (France). DXIS targeted to retrofit all the panoramic models.
1997 – SIDEXIS, of Siemens (currently Sirona Dental Systems, Germany) offered a digital option for Ortophos Plus panoramic unit, DigiPan of Trophy Radiology (France) offered a digital option for the OP100 panoramic made by Instrumentarium (Finland).
1998–2004 – many panoramic manufacturers offered their own digital systems.
Research
Panoramic radiographs have the capability to demonstrate a portion of the neck and display atheromas (calcifications in the carotid artery) which are an indication of both local and generalized (systemic) atherosclerosis. Atherosclerosis of the coronary arteries leading to myocardial infarction (heart attack), and atherosclerosis of the carotid artery leading to stroke are the number one and number three most common causes of death in the United States.[6]
There is interest to look at panoramic radiographs as a screening tool, however further data is needed with regards if it is able to make a meaningful difference in outcomes.[7]
Epidemiology: general public and high risk groups
Additional research projects have further determined the prevalence rate of these atheromas in the general population (3–5%)
Dental infection and atherosclerosis
Atherosclerosis is attributed to risk factors that include cigarette smoking,
See also
References
- ^ Langlais, Robert. "RECTANGULAR COLLIMATION No longer a matter of choice!".
- ^ Dental Radiographic Examinations: Recommendations For Patient Selection And Limiting Radiation Exposure. Am Dent Assoc, U.S. Dept of Health and Human Services, FDA. Revised: 2012
- ^ Stuart C. White, Micheal J Pharoh, Oral Radiology and Interpretation Mosby 2005
- ^ ISBN 978-0-443-10168-7.
- ^ "Apparatus and method for producing digital panoramic x-ray images".
- ^ American Heart Association’s Heart Disease and Stroke Statistics—2010 Update [1]
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