What is a Periapical Radiograph? – Let’s Find Out

Dental x- rays are one of the greatest innovations in the field of dentistry. They provide a clear view of conditions that may affect the tooth, root, and surrounding bone. Moreover, they help to find problems that cannot be seen during an oral examination.

Typically, there is a wide range of dental x-rays used for several purposes. One among them is a periapical radiograph. Periapical x-rays are the most common diagnostic radiographs taken on a routine basis in the dental office. A periapical radiograph is an intraoral x-ray that provides a selective view of dental conditions such as tooth decay, root caries, progressive bone loss, and apical tooth infections.


It requires high precision and technique to take a periapical radiograph. Ideally, a perfect periapical view is formed when the x-ray beam meets the film at the right angle. Two main techniques help to reproduce this position – the bisecting angle technique and the paralleling technique. Let’s quickly dive into the article to take a closer look at the unique techniques of periapical radiography. Moreover, we will discuss the uses, frequency, and cost of taking a periapical radiograph.

What is a periapical radiograph?

A periapical radiograph is an intraoral x-ray that is used to detect any abnormalities of the tooth root and surrounding bone. It evaluates the periapical area of the tooth. Typically, a periapical x-ray captures a particular area of the jaw and shows the tooth of concern from the exposed crown to the tip of the root. Additionally, it also views one or two adjacent teeth and provides detailed information about the surrounding alveolar bone. (1)

What is the use of a periapical radiograph?

There are several indications for periapical radiography. Some of the primary uses include the following –

In adults,

  • To detect periapical infection or inflammation
  • Check for traumatic fractures of the teeth and surrounding alveolar bone (2)
  • Assess the periodontal status of a person
  • Assess the root morphology before extraction procedures
  • Diagnostic aid during endodontic procedures
  • Assessment of periapical area before and after an apical surgery
  • Evaluation of periapical abscess or cyst
  • Post-operative evaluation of an implant (3)

In children, a periapical x-ray may be used for the following reasons –

  • Document the presence and position of an unerupted tooth (4)
  • To monitor an early carious lesion
  • To monitor the developing wisdom teeth
  • Check for impacted teeth

What is the procedure for taking a periapical radiograph?

Ideally, to take a perfect periapical radiograph, few criteria must be taken into consideration –

  • The tooth of concern and the x-ray film should be placed in close contact with each other
  • It is crucial to put the film parallel to the tooth so that the x-ray beams can meet the film at right angles
  • For anterior teeth, the film can be placed vertically in contrast to the horizontal placement for posterior teeth

Two main techniques allow the dentist or the dental assistant to take an ideal periapical radiograph. These techniques are explained as follows –

Paralleling technique

In this technique, the film is placed parallel to the tooth under investigation. Paralleling technique uses a film holder to fix the film in the desired position and an x-ray beam aiming device. This device helps to aim the head of the x-ray tube at right angles to the film and the tooth. (5) Paralleling technique is most commonly used in dentistry because of the following benefits –

  • It allows reproducibility to maintain uniformity in the follow-up radiographs
  • It satisfies all of the ideal criteria as mentioned above

Bisecting angle technique

The bisecting angle technique uses a geometrical principle, which equates the length of the tooth in the mouth to the length of the tooth captured on the film. In this technique, the film is placed as close to the concerned tooth as possible without bending or modifying the shape of the x-ray film. The angle formed between the long axis of the tooth and the long axis of the film is assessed and bisected mentally. (6)

The head of the x-ray tube is positioned at right angles to the bisecting angle and aimed to meet the apical area of the tooth.

How often should you get a periapical radiograph?

During the first dental visit, the dentist may usually require a full mouth series of the periapical radiograph. This may sum up to a total of 14 – 21 x-ray films. After this, a periapical radiograph may be scheduled, depending on the risk and progression of the disease.

Periapical radiographs often play an essential part in documenting a child’s dental development. Periodic x-ray follows ups may be done every six months to one year to record the eruption pattern and development of the permanent teeth. (7) Periapical x-rays are safe even if they are taken periodically to monitor a condition. The amount of radiation exposure from periapical radiograph is minimal.

Frequent exposures do not pose a treat to the health of the patient. Additionally, every dental x-ray is taken under universal precautions, which include the use of lead apron and thyroid collar. Such type of protection further reduces the risk of radiation exposure.

How much does a periapical radiograph cost?

Usually, a single periapical x-ray may cost between $15 – $25. However, the cost of a full mouth series consisting of 14 – 18 radiographs may shoot up to $100 – $200. Most dental insurance covers the cost of diagnostic and follow – up x-rays.

Take away message

Periapical radiographs are one of the most commonly used x-rays in the field of dentistry. They mainly focus on viewing detailed information about dental conditions associated with a particular tooth. Moreover, it determines the progression of the infection and its effects on the surrounding bone. Periapical radiographs are also used to monitor the growth, development, and eruption rate of teeth in children and adolescents.


A periapical radiograph is unique in terms of the techniques used to take the x-ray. Typically, there are two techniques, namely paralleling and bisecting angle technique, that are used to accurately record the details of the tooth on an x-ray film.

An individual may require a single or series of periapical radiograph depending on the risk of disease, age, and disease progression. However, getting a periapical radiograph is safe as it has minimal radiation exposure, which may not affect the health of the patient. If you are looking to get a periapical radiograph, consult your nearest dentist to know more about this unique dental x-ray.


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