Extraoral X-ray photographs are made with the film outside the mouth. These are not familiar as intraoral X-rays. They are considered as the big picture X-rays. These X-rays provide the picture of jaw and skull along with the teeth. X-rays examination help in tracking the growth and development of the teeth, shows the status of the impacted teeth, examines the relation between teeth and jaw, and helps in examining the bones of the face, etc.
Extraoral X-rays do not show up as detailed as intraoral X-rays. So, they are not used for detecting the cavities or flaws in the individual teeth. There are many types of extraoral X-rays and they are detailed below.
Panoramic X-ray
These X-ray images are useful in identifying the position of fully emerged, and also the emerging teeth, which helps in detecting the impacted teeth, and assist in diagnosing the tumors. In a single X-ray, it shows the entire mouth area i.e., the teeth of both upper and lower jaws. For taking these X-rays, they require a special machine. It uses less radiation as compared to the intraoral X-rays, when capturing the image of your mouth in the film.
Tomograms
This X-ray image shows you a particular area or structure of the mouth, blurring all other layers of the mouth. Tomograms are useful in identifying the structures that are difficult to observe; because, the other structures are very close to the structure or the layer to be viewed.
Cephalometric projections
These X-rays are taken of full side of the mouth. These X-rays are used to look the teeth and its relation with the jaw. This type of X-rays are used by the dentists for developing the treatment plans.
Cone-beam and standard computed tomography (CT)
The cone-beam CT is used for dental implant selection and placement; whereas, the standard CT is used for determining the size and placement location for implants. Cone-beam CT gives the 3-dimensional images and uses less radiation when compared to the standard CT scan.
Sialography
Sialography is used for testing the problems with salivary glands such as blockages. These X-rays involve the visualization of the salivary glands and also the injection of radiopaque contrast agent called a dye, through which glands are visible on the X-ray film.
These are the various types of extraoral or big-picture X-rays, which help in detecting various dental problems. So, before taking the X-ray, diagnose which type of X-ray will be suitable for your dental problem with the help of dentist.