There are many types of dental radiographs (x-rays) that your dentist can use in the course of treating your dental needs and keeping your mouth healthy and comfortable and your smile beautiful. I would like to discuss the four types that are used most frequently.
The simplest and most basic are called Bite-Wing radiographs. They are usually four in number (two on each side of the mouth), and they are generally taken once a year by your restorative (general) dentist during annual check-up visits. They are excellent for evaluating the enamel crowns of the teeth (the part we see above the gum line). They allow the dentist to check your back teeth for decay. They also allow your dentist to evaluate the condition of existing restorations (fillings and crowns) under the surface and to check the marginal fit of these restorations.
The problem with these bite-wing radiographs is they provide little or no information about the roots of the teeth and the surrounding bone. They also do not provide any information about the front teeth.
Periapical radiographs make up for these limitations of bite-wing radiographs. A “full set” provides a complete view of all of the teeth (front and back) including the roots and a picture of the surrounding bone that supports the roots and holds the teeth in place. They help show the height of bone around the roots, which helps confirm periodontal health or disease (along with periodontal probing). They can also show decay in the roots and other pathologies, most notably developing root canal infections that are not visible and are often without symptoms (pain and swelling).
A full set of periapical radiographs usually requires 14 films (assuming a full dentition). These are certainly taken by the Periodontist since our focus is the gums and the underlying bone. They are generally recommended once every three years. Single periapical films can be taken on an as needed basis as specific problems and questions arise.
Both of these types of films are taken intraorally. That is, the film or sensor is placed inside the mouth alongside the teeth. Today, a digital sensor has replaced actual film. It requires less radiation and can improve our diagnostic capabilities. In Part 2 we will discuss the two other types of dental radiographs that are commonly used.