In today's article, I will discuss the panoramic radiograph, one of the remaining two other types of dental radiographs that are in common use. This is one of the types of radiographs that are classified as an extra-oral film, the film is positioned outside the mouth. The two types of radiographs that were described in Part 1 are called intraoral films. This means the actual film or sensor is placed inside the mouth alongside the teeth that are being evaluated.
In the case of the panoramic film, the film or sensor travels entirely around the outside of the head, 360 degrees. This is particularly good for people that tend to gag or find the intraoral films uncomfortable.
The other advantage of the panoramic film is that it shows parts of the upper and lower jaws that cannot be reached with the intraoral films. This includes the full extent of the lower jaw bone and the position of the nerve and blood vessel that runs through this bone from back to front. This is valuable information since we want to avoid damage to these structures during surgery, including implant placement.
In the upper jaw, we can see the sinus spaces above the upper back teeth. Again, this is valuable information during surgery such as sinus grafts and placement of implants to replace the upper back teeth.
It should be noted that it is also possible, in this type of film, to visualize wisdom teeth (third molars) that are buried under the gum and even some other structures in the head such as the carotid arteries. These are the two main arteries that bring blood to the head and brain. Like arteries in the heart and elsewhere in the body, they can become blocked with plaques which often contain calcium. These calcium filled plaques can be seen in the panoramic film.
One disadvantage of the panoramic film is that it does not provide great clarity or detail about the individual teeth. Therefore, it is not a great tool to check for decay or the fit of restorations like fillings and crowns, so the two types of intraoral films mentioned in part 1 are still very necessary.
We will discuss the other extraoral film that is commonly used in Part 3.