What is an orthopantomography?
Orthopantomography is an extraoral radiographic technique in which the ray source and the receiving plate are external to the oral cavity or mouth, performing a synchronous movement around the patient’s head.
It is a panoramic X-ray on a single film, a single general image of the mouth showing the jaws, jaw and teeth. Therefore, it is of primary use in the mandibular dentus maxillo area.
It is a radiographic examination that allows you to accurately plan a large number of dental or dental treatments.
It allows obtaining radiographic data on the masticated apparatus (teeth and bone) and the adjacent structures, allowing the evaluation of the normal anatomy or most of the pathological or disease conditions.
What is it for?
Orthopantomography is a radiographic technique that allows to obtain panoramic radiographs capable of showing complex anatomical structures, like the entire oral cavity.
What can be seen on an orthopantomography?
It includes both dental arches (upper jaw and mandible), maxillary sinuses, temporomandibular joints (TMJ) and less sharp soft tissue structures. The goal of orthopantomography is to translate all these anatomical structures into a two-dimensional (two-dimensional) radiographic image.
Orthopantomography is very sensitive to the way it is made since it is a modified (curved) type of linear tomography, or radiography of a certain layer, which aims to blur the structures not contained in that corridor or layer.
In orthopantomography and with the patient well positioned, the arcades are clearly visualized because they are located within the cutting corridor and the other structures are blurred more the further away they are from it. The cutting aisle has a variable thickness depending on the manufacturer. It is usually narrower in the anterior segment (from canine to canine) than in the posterior, because the teeth are narrower than the molars.
Given the importance of the correct positioning of the patient’s head, all orthopantomographs have mechanisms for proper positioning, as the arches must coincide with the cutting corridor of the device. Since this can be quite narrow, it is vital to follow the manufacturer’s instructions for the correct positioning of the patient in order to obtain a quality X-ray.
What does the orthopantomography detect?
With orthopantomography we manage to study in detail the entire dental structure, allowing:
- Detect the presence of tooth decay.
- The extent of tooth decay and whether there is contact with the dental nerve.
- The presence of widespread infectious processes.
- Teeth that have not yet erupted.
- The amount of bone structure remaining to be able to put dental implants.
- Pathological bone lesions.
How does it work?
The synchronous movement of the tube and plate or receiver determines that a specific area of the head, the focal aisle, is projected clearly onto the plate and what is outside it appears blurred.
How long does the orthopantomography last?
The test is about 5 minutes long. It is perfect for small children due to the simplicity of the exam and its speed.
Facts to keep in mind
In a good panoramic X-ray, the jaw is U-shaped, the condyles of the temporomandibular joint are located about 2.5 cm from the lateral edges of the film and one third of the upper edge of the film.
The occlusal or chewing plane shows a slight curve or “smile line” upwards.
The roots of the anterior maxillary and mandibular teeth are well identified with little distortion, and the magnification is symmetrical and equal on both sides of the midline.
Differences with other X-Rays
The image receiver in extraoral radiography is a combination of two intensifier screens with an interspersed film, which are enclosed in a light-tight container, called a cassette. A cassette can be soft or stiff.
Each intensifying screen contains a phosphoric layer that fluoresces when activated by X radiation that has penetrated the patient and cassette. This fluorescence is what the film exposes.
This method of exposure differs from conventional intraorally x-rays, where X-rays expose the film directly. The films used in panoramic images are 10-60 times more sensitive to fluorescence than X-rays; therefore, the amount of radiation needed to produce a high-quality film is lower when using screens.
When the radiation beam and the image receiver surround the patient, the image is recorded on the film in vertical increments, limited by the same narrowness of the beam.
Most devices have some type of position control, such as lights or plastic guides, to place the patient properly with respect to the three main axes: anterior-posterior, vertical and mediaagital alignment.
In order to determine in an orthopantomography which parameters have gone wrong, the standard parameters of normality must be known and evaluate what type of error has been made (patient positioning, inadequate exposure values …).
Orthopantomography: essential tool for dentists
Today, orthopantomography is an essential tool for dentists that allows them to diagnose many of the pathologies or diseases that the patient may suffer and plan treatment properly.
In a first quality visit, the examination of the mouth, with the teeth and soft tissues, is usually combined, along with the radiological examination that includes an orthopantomography and two x-rays of bite fins.
In short, it is one of the best ways of oral inspection to be able to see from the jaws, the jaw to all the teeth.
