To make a correct diagnosis it is extremely important to carry out a thorough inspection and examination. Certain findings are not revealed by mere inspection like those findings that are within a tooth or jaw bone. In such cases we need diagnostic tools like X-rays. There are various types of X-rays used in dentistry. Each of them has got its own set of uses.

We can classify them broadly as

Intra-Oral X-Rays- This type of X-ray is taken with the films kept within the mouth like periapical (PA) X-ray or bitewing. We get a detailed view of the teeth and the surrounding alveolar bone so it is extremely useful in detecting dental caries.

Extra-Oral X-Rays- This type of X-ray is recorded with the film outside the mouth like panoramic X-rays. These X-rays mainly focus on the jaws and skull. The minute details of teeth cannot be determined with extra-oral X-rays so these are used for detecting TMJ (Temporomandibular Joint) problems or detecting impacted teeth.

Intraoral X-Rays

One Film Periapical

Periapical X-rays, as the name suggests, are meant to shows the tooth with the area around the apex of the tooth (peri= around; apical= tooth apex).  Basically, periapical X-rays show one whole tooth and parts of adjacent teeth right from the crown portion till the root tip with the jaw bone around the tips of the roots.

Uses of One Film Periapical

1.    Detection of periapical lesions like cyst, abscess or granuloma
2.    Detection of root abnormalities which is extremely important prior to extraction or root canal treatment.
3.    Surrounding bone abnormalities can be made out

Two Film Periapical

Two films come together as a packet. With one exposure, two identical periapical X-rays can be obtained. One of them can be kept with the dentist for record purposes and other can be handed over to the patient for further consultation. The uses are similar to the one fil periapical itself.


This type of X-ray show upper and lower teeth of a particular area. Generally, bitewing is recorded for posterior teeth.

The significance of bitewings are

1.    Detection of interdental caries
2.    Detection of overhanging margins of fillings
3.    To ensure the proper fit of a crown or cat restoration
4.    Detect any problems related to bone density due to periodontal disease.


This type of X-ray is larger compared to the other intraoral X-rays. It shows either upper or lower jaw with teeth. The entire arch of teeth is shown. This X-ray is used to detect the abnormalities related to anatomic structures like palate or floor of the mouth. Sialoliths (salivary gland stones) can also be detected by occlusal X-rays.

Full Mouth Series

This involves the complete set of intraoral X-rays of an individual. The complete set has

1.    Four bitewings
2.    Eight periapical X-rays of posterior teeth
3.    Six periapical X-rays of anterior teeth

Nowadays, dentist try to avoid full mouth series due to risk of radiation hazard involved behind exposing the patient for so many times for recording X-rays.

Extraoral X-Rays

Panorex X-Rays

They are also called as panoramic radiograph. This X-ray gives the full view of upper and the lower jaw with the complete set of teeth.

Uses of Panorex X-Rays

1.    Detection of TMJ abnormalities
2.    Detection of oral cancer
3.    Detection of impacted teeth especially wisdom teeth
4.    For orthodontic assessments

Ceph X-Rays

They are also called as cephalometric X-rays. They give the complete picture of the side of the head showing the relation of the jaw to the skull and the profile of the patient. They are mainly used in the beginning of orthodontic treatment and during other stages of the treatment for the purpose of comparison and for obtaining a better understanding of the changes brought about by the treatment.

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