What is Radiovisiography?

July 03, 2021

The oral cavity is an area of the face that houses vital structures responsible for basic functions of the human body like chewing, speaking, facial expressions, etc. The wheels of these intricate mechanisms are in a smooth motion only because of the dense network of blood supply and nerves in those regions. Supporting hard tissues like ligaments, cartilages and bones further add to the integrity of these structures.

A visit to the dentist is most often due to a feeling of discomfort in the teeth or the gums. Upon inspection, the naked eye of the dentist can check for any abnormal discolorations, fractured teeth, improper bite or any other visibly abnormal findings in the oral cavity. A dentist uses an explorer or a probe, and a mouth mirror to check for the depth of cavities, consistency of soft tissue masses or the health of the tissue complex surrounding each tooth (periodontium).

Diagnosis with dental x-rays

In most cases, a dental diagnosis requires an x-ray. Since each tooth's roots serve as a passage for their blood and nervous supply, it is important to evaluate the changes surrounding that region. The part of the tooth that consists of blood vessels and nerves is called the pulp. When a cavity is deep, the infection can reach the pulp, thereby causing pain. The extent of this carious lesion can be assessed by examining its depth with respect to the pulp.

Intraoral periapical radiograph (IOPAR)

The tooth and its surrounding structures in a dental x-ray [intra oral peri-apical radiograph (IOPAR)] can be viewed as black and white structures just like in any other x-ray. The pulp is viewed in black whereas the hard tissues covering it (enamel and dentin) are seen in white. The dental decay is seen as a blackish patch that evades the enamel and dentin. The depth of this lesion if deep, can be appreciated as approaching or involving the pulp. Based on this the needed diagnosis is made and the treatment plan is made.

What is radiovisiography (RVG)?

The IOPAR can certainly be helpful clinically and is even used routinely today. However, the image on the x-ray develops after the film is dipped in certain chemicals for specific period of time. A major disadvantage of the IOPAR is the increased exposure time to radiations and the chances of failure that may occur if the film is not positioned properly in the oral cavity. It was in 1987, when Dr. Francis Mouyen brought digital technology to the world of radiography. Termed as digital imaging, the radiovisiography (RVG) soon became a popular choice.

The RVG utilizes a sensor, a vital component of the system that was developed by Paul Suni. This sensor is placed in the patient's mouth. When an external source of radiation is angled in line with the sensor that is placed inside the mouth, a push of a button can show up the x-ray image on the computer. RVG uses a very less exposure time and is obviously faster than the conventional IOPAR.

The upgradation of various softwares has now made it possible for dentists to edit the digital image (produced by RVG) in order to get a better understanding of the underlying conditions. These edits include changing the contrast resolution, brightness, heat mapping, etc. Moreover, RVG has made it possible for dentists to save the progress of the treatment as image storage has now become easier through digital means.

Radiovisiography (RVG) advantages

RVG has proven to reduce the radiation exposure to patients by 80%. Talking about numbers, a conventional IOPAR gives us an X-ray image that has 16 to 25 shades of grey. But in a RVG, the image clarity is such, that it utilizes 256 shades of grey to give us a distinct idea of the patient's dental condition.

The RVG can be an expensive investment to begin with for a dentist. But it gives three major advantages to balance the scale. Firstly, if you are using a conventional IOPAR, you need to have chemicals stored at specific temperatures in specific environments that help in the developing of image on the film. This requires high maintenance and can be tedious. Secondly, a RVG makes the patient realize that his or her dentist is highly equipped with modern technology that instantly produces the x-ray. Thirdly, data (images) on the RVG can be mailed or sent to the patient by any digital means, making it easier to maintain the records.

RVG is now used in most dental clinics. It has proven to be an effective source of diagnosing dental decay, fractures of the tooth or underlying bones, identifying the presence of abscess or tumours or cyst, tracking the development of permanent teeth in children, etc. All this eventually has led to better formulation of treatment plans and visualising the effects before and faster the treatment in a much better way.

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