Extraoral Radiographic Views

ORTHOPANTOGRAM

ORTHOPANTOGRAM gives a panoramic view of the mandible and teeth which is performed using a technique called “tomography”. Tomography the Greek word meaning “X-ray technique for making radiographs of layers of tissue in depth, without the interference of tissue above and below that level”

EXAMPLE OF IMAGES   

Figure 1: Anatomy structures that shown in OPG

 Figure 2: OPG of patient who has wisdom teeth

EXAMPLE OF OPG MACHINES

1) Vatech Flex 3D

     

2) Vatech PAX UNI3D

3) Bio- Meditex System

4) ORC-1A Panoramic X-ray Unit for Oral Examination (OPG)

REASONS FOR OPG REQUESTS: 

1) Dental Disease (eg: Caries)

                

2) Extraction of teeth (eg: wisdom teeth)

3) Teeth Abnormalities

4) Trauma to teeth and facial skeleton 

5) Transplant workup

ADVANTAGES AND DISADVANTAGES OF OPG 

BIL	ADVANTAGES	DISADVANTAGES
1	Low radiation dose	High Cost
2	Convenient, easy and fast	Tendency to produce overlapping teeth images
3	Broad anatomic region is imaged	Image quality :  show magnification, geometric distortion and poor definition
4	Can performed on patients who cannot open their mouth	Superimposition of the spinal column on the anterior portion of the OPG

HOW DOES IT WORK?

The x-ray tube moves around the head, the x-ray film moves in the opposite direction behind your head. This generates an image slice where the mandible and teeth are in focus, and the other structures are blurred

POSITIONING OF PATIENT

1. Remove any bulky clothing and radio-opaque objects from the region of interest

2. The equipment is set up and the explanation is given to the patient

3.  15x30 cm image receptor is used

4.  Ask the patient to hold the handles and adopting a ‘skiing’ position

5. Tilted the head downwards until the Frankfort plane is parallel with the floor

6. Adjust the machine height to allow the patient to bite block and the patient’s chin should be placed on the rest.

7. Ensure the patient is not rotated and close the head restraints.

8. The patient is asked to place their tongue on the roof of their mouth to reduce the air shadow and is asked to keep still for 20 seconds

9. Exposed and  observe the patent carefully.      

For further understanding, please kindly refer the following video clips :