Radiography is an essential diagnostic tool in dentistry without it. 60% of the cavities in the mouth would not be diagnosed in time. This is why your dentists will suggest that you have x-rays taken regularly. X-rays are inevitably in no way beneficial for health. However, it is essential to know that with today’s technology. The doses of radiation are not what they used to be. For example, we know that a dose of radiation used for two x-rays with the protection of the lead apron is equivalent to 0.5 REM. This amount represents what a human being absorbs during a day spent in the Sun or when a cigarette is smoked, or a glass of wine is drunk. All these bad habits put you in the presence of the same dose of REM. Several kinds of dental x-ray exist. First, there are twin radiographs. This procedure allows the diagnosis of cavities between the teeth. Periodical radiography is another kind of dental radiography. It is used to detect specific lesions such as an abscessed assist or any disorder located at the tip of the root. The panoramic radiograph is often used for good follow-up of the jaw structures. This type of x-ray provides a full view of the tissues that make up the lower part of the cranium. A panoramic x-ray every three to five years is recommended unless a particular disorder exists. The must be monitored more closely cephalometric radiography can be used to evaluate the growth of the jaw scanners can also be necessary for the laying of implants or for certain surgeries that require the knowledge of the location of all the tissues bordering the region concerned the last x-ray which we sometimes turn to is transcranial radiograph this type of x-ray is used to study the jaw joint finally when a dentist recommends one of these x-rays it is important to remember that it has been proposed for reasons of safety without these many disorders could not be diagnosed in time.
We will be looking at the most common types of radiographs or x-rays that we take in dentistry. Let’s look at the types of x-rays that we take in dentistry. They can broadly be divided into two categories – we have intra-oral radiographs, i.e. where the film is placed inside the mouth. We also have extra-oral radiographs where the film is outside the mouth.
Types of Dental X-rays You NEED to Know
Let’s first look at intra-oral radiographs, as these will form the basis for most of the work you do in practice. So firstly we have bitewing radiographs. Bitewing radiographs are routinely done for patients as part of their caries assessment – we do one for the left side and one for the right side. Typically they’re done horizontally; however, they can be done vertically if necessary.
There are two main reasons bitewings are very helpful. The first one is to diagnose caries – this may be interproximal caries or caries underneath restorations. Additionally, bitewings are very helpful in assessing bone levels. This includes healthy bone levels and a very early bone loss seen in periodontal disease. Next, we have periapical radiographs or around the apex.
A periapical radiograph aims to show you more detail surrounding the apices of teeth. There are many reasons we may do periapical radiographs. We often do them to diagnose periapical pathology surrounding a tooth and then embark upon endodontic treatment. We often use peripheral radiographs to assess our endodontic treatment. Aside from endodontic treatment, periapical radiographs are helpful in a number of other areas. In patients with periodontal disease, peripheral radiographs help us assess the bone levels in more moderate to severe bone loss cases.
Additionally, we can use peripheral radiographs to localize ectopic teeth, which would be done using a parallax technique. Finally, periapical radiographs can also be very helpful if we look at the root morphology before extracting a tooth – this is particularly useful with third molar teeth.
Occlusal Radiographs
Next, we have occlusal radiographs, in which case we can have a maxillary or an upper occlusal, or we can have a mandibular or a lower occlusal. For an occlusal radiograph, the patient will usually have the film between their teeth, so they will bite down on the film in a horizontal place. Because the patient places the film between their teeth, occlusal can be pretty helpful in patients who have trismus. We can use occlusal views for a range of reasons. Some of these include localizing ectopic teeth or impacted teeth identifying salivary calculi; for example, we may do a lower occlusal in the submandibular gland. They can also be helpful to locate foreign bodies or other pathology within the jaw, for example, cysts. So there, we’ve looked at the intra-oral radiographs that include bitewing radiographs, periapical radiographs and occlusal radiographs.
Extra-Oral Radiographs
Let’s now look at the extra-oral radiographs. The most common extra-oral radiograph that you’re likely to encounter is a panoramic film or an OPT, DPT or OPG. Panoramic films involve the patient standing with their teeth on a bite fork and a machine rotating around their head, giving us a complete overview of their dentition and surrounding anatomy, including the jaws.
An OPT can often provide sufficient detail to carry out the treatment. They don’t necessarily give the detail that an intra-oral film would provide. However, they give an overall view of the patient’s dentition, for example, patients who may not tolerate intra-oral radiographs due to the size of the film or they’ve got a bad gag reflex. However, OPTs are particularly useful in assessing third molars before extraction to look at the interaction between the wisdom tooth and the inferior alveolar nerve. OPT is also beneficial to determine fractures of the mandible and other pathologies such as cysts. An advantage with OPT is a lot of the new machines will allow you to use sectional OPTs so you could do a left, you could do a correct view, you could just get the TMJs, or you could cut the TMJs off. This is helpful when considering the radiation dose being exposed to the patients. The impact on the parotid glands is more significant than other surrounding structures, and therefore if you can avoid exposing them to radiation, this is beneficial to the patient.
Oblique Lateral Films
Oblique lateral films can be helpful, particularly in children, to help with a diagnosis where they can’t tolerate an intra-oral film. An oblique lateral would usually involve the child sitting at 90 degrees on their chair with their face put against a sensor. Then we have the beam coming at an angle obliquely to their jaw. This will then ideally capture both sides in terms of the posterior teeth. Along with assessing things like caries, oblique laterals can be used to identify other jaw pathology and unerupted teeth. Next, we have posteroanterior films or PA films.
These can either be of the skull or the mandible. We can use the PA skull to assess fractures of the skull vault or other pathology such as bone abnormalities like Paget’s disease.
For this type of imaging, the patient sits facing the x-ray film, they tip their head slightly, and their forehead and the tip of the nose should be touching the film. The x-ray tube is then placed behind the patient horizontally in line with the skull base. This then captures the image, which will let us look at things like the sinuses, head, any of the fractures. For a PA mandible, the patient sits in the same way; however, we lower the level of the x-ray tube, keeping it in the horizontal to the story of the mandibular rami. This will provide us with more information relating to the mandible. We typically get PA mandibles when we’re assessing fractures of the mandible. Generally, in any fracture case, we want to be getting two views from different directions, which will allow us to determine the displacement of a fracture. For example, suppose you consider an OPT, as we may say to patients. In that case, x-rays are two-dimensional images of a 3D structure, so on an OPT, the mandible may look fine, but when you take a PA mandible, you can see it’s displaced in a direction you couldn’t see on the OPT. Next, we have the occipitomental view, and again, we typically take this view to assess fractures of the mid-face or any pathology associated with the sinuses.
So because we tend to assess fractures with this view, we tend to take two different views at different angles. The patient will face the image receptor to take the occipitomental view.
Rather than having their head tilted forwards, they’ll be listed backwards such that their chin touches the image receptor. We then line up the x-ray tube horizontally to the occiput behind them. This will then capture the OM zero degrees view. Then to take another view, we would simply move the x-ray beam to a certain angle, typically something like 30 degrees to the horizontal, and so the beam would be coming at a higher greatly different view. We can then look at these two views, and this will help us identify any fractures and any displacement. And finally, we have cephalometric imaging or lateral Ceph. These are taken using a particular machine called the Cephalotus. Lateral Cephs are mainly used in orthodontic treatment planning and treatment progression. You could take lateral Cephs along the patient’s journey and compare their initial imaging to their final imaging to see the change.
How We Help You With Dental X-Rays
Some people dislike dental x-rays because gagging the sensor can be uncomfortable and elicit a gag reflex, but there are many ways to prevent this. X-rays can be a pleasant experience if you communicate and tell your concerns to the person taking your x-rays. If you’re nervous about gagging, tell them so they can help you through the process.
