Panoramic radiograph

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.

Dental X-rays' radiology is moving from film technology (involving a chemical developing process) to digital X-ray technology, which is based on electronic sensors and computers. One of the principal advantages compared to film based systems is the much greater exposure latitude. This means many fewer repeated scans, which reduces costs and also reduces patient exposure to radiation. Lost X-rays can also be reprinted if the digital file is saved. Other significant advantages include instantly viewable images, the ability to enhance images, the ability to email images to practitioners and clients (without needing to digitize them first), easy and reliable document handling, reduced X-ray exposure, that no darkroom is required, and that no chemicals are used.

One particular type of digital system uses a photostimulable phosphor plate (aka PSP - Phosphor Plate) in place of the film. After X-ray exposure the plate (sheet) is placed in a special scanner where the latent formed image is retrieved point by point and digitized, using a laser light scanning. The digitized images are stored and displayed on the computer screen. This method is in between old film based technology and the current direct digital imaging technology. It is similar to the film process because it involves the same image support handling and differs because the chemical development process is replaced by the scanning process. This is not much faster than film processing and the resolution and sensitivity performances are contested. However it has the clear advantage of being able to fit with any existing equipment without any modification because it replaces just the existing film.

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.

• 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]

1985–1991 – The first attempt to build a dental digital panoramic was of McDavid et al. at UTHSCSA.[5] Their idea was based on a linear pixel array(single pixel column) sensor which was not appropriate for such an application because: a) there is no tomographic effect; b) huge difficulties to collimate the X-rays beam and to control the X-ray dose delivered to the patient; c) poor generator efficiency.

DXIS - real time display

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.

Additional research projects have further determined the prevalence rate of these atheromas in the general population (3–5%)[8][9] and among high-risk groups (over 25% in: recent stroke victims,[10] individuals with obstructive sleep apnea syndrome,[11][12][13] postmenopausal women,[14] type 2 diabetics,[15][13][16] individuals with dilated cardiomyopathy,[17][13] and among individuals who have received radiotherapy directed at the neck,[18][19]). These findings have been corroborated by other several other researchers.[20][21][22][23][13]

Atherosclerosis is attributed to risk factors that include cigarette smoking, hyperlipidemia, obesity, diabetes mellitus, and hypertension (high blood pressure). These factors, however, do not fully account for the risk of disease. Atherosclerosis has been conceptualized as a chronic inflammatory response to endothelial cell injury[24] and dysfunction possibly arising from chronic dental infection. In 2010, using the previously validated Mattila panoramic radiographic index to quantify the totality of dental infection (i.e., periapical and furcal lesions, pericoronitis sites, carious tooth roots, teeth with pulpal caries, and vertical bony defects), Friedlander’s group determined that individuals with carotid artery atheromas on their panoramic radiographs had significantly greater amounts of dental infection/inflammation than atherogenic risk-matched controls devoid of radiographic atheromas.[25][26] While the Mattila index had been previously used to relate the extent of dental infection to coronary artery disease, this research is the first to link the full range of dental disease that it measures to panoramic radiographs evidencing calcified carotid artery atherosclerosis.