Oral Radiology – Extraoral Radiograph


What is radiography? Radiography is defined as the technique of examining the body by directing X-rays through it to produce various radiographic images on a photographic film or a fluoroscope. Radiography has been widely used in medical as well as dental healthcare for various purposes.

In continuation with our previous post on Oral Radiology where we discussed about Intra-oral Radiographs, in this post we will find out about the other type - Extra-oral Radiography. The most common type of Extra-Oral Radiograph consists of Orthopantomogram (OPG).

Orthopantomogram (OPG), also known as an “orthopantogram” or “Panorex”, is a single tomographic image of the facial structures that include both upper and lower dental arches and their supporting structures.


OPGs are indicated for the following conditions:

  • Evaluation of teeth development in children

  • Assessment for orthodontic therapy

  • Establishment of the size & site of oral lesions

  • Diagnosis of oral lesions

  • Detection of bone fractures

  • Assessment of third molars

  • Investigation of TMJ dysfunction

  • Assessment of jaw bones

  • Evaluation of developmental anomalies

What are the advantages of this radiographic technique?

  • Being a simple radiographic technique

  • Convenient radiographic technique

  • Having lower radiation dose

  • Useful for mass screening

  • Helping in object/lesion localization in human body

What are the disadvantages of orthopantomogram?

  • Geometric distortion of the radiographic image

  • Radiographic image magnification

  • Overlapping of teeth in the radiographic images

  • High cost

In a nutshell, the advancements in technology have made dental practise more comfortable, effective and time saving for the patients. Radiography does play a very essential role in the practise of dentistry by helping in the diagnosis, evaluation, management, and treatment planning of various dental conditions/diseases.



Tommy Wong

by Tommy Wong

A full-time Dental Student passionate to make a dent in the World of Dentistry. All through my dentistry journey, I have realised that there is still a lack of Oral Health Education to the public globally. This leads to high prevalence of Oral Diseases among the human population. With this mission, we have established GlobalDentalPro – Your Oral Health Educator with the mission to promote Oral Health globally to enable people to increase control over, and to improve their Oral Health & thus General Health. View all articles by Tommy Wong.


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