How does dental X-ray work
During the dental examination, the X-rays emitted by the dental X-ray machine will pass through your mouth. Before the X-ray hits the X-ray film, most of it will be absorbed by the dense tissues in the oral cavity (such as teeth and bones), and a small amount will be absorbed by the soft tissues of the oral cavity (such as cheeks and gums). The X-ray film is thus produced. In the X-ray film, the teeth will appear very bright, because only a small amount of X-rays pass through the teeth and hit the X-ray film. In the same way, signs of tooth decay, infection and gum disease, including changes in bones and ligaments that keep teeth stable, will be reflected in X-rays. These areas will be relatively dark because more X-rays pass through them. The brightness of dental restorations (fillings, crowns) in X-ray films depends on the restoration materials used. Dentists can find the lesion safely and accurately by analyzing X-ray films.
Next, let's take a look at the precautions for dental X-rays.
Preventive measures for dental X-ray
According to the "Provisions on Health Protection of Medical Diagnostic X-rays", X-ray machines should be placed in a separate X-ray room. And the area of the computer room should be large enough. Generally, the X-ray machine room below 100mA should be no smaller than 24 square meters. This standard applies to oral X-ray machines. Dental X-ray machines must be placed in a separate computer room with protective equipment, and X-ray machines are not allowed to be placed in the examination and diagnosis room. The setting of the X-ray machine room must fully consider the safety of the surrounding environment.
Filming process: Radiologists must perform exposure in a shielded room, and general lead screens are unsafe for protection. After testing, at the operator behind the lead screen 1m away from the dental X-ray handpiece, the amount of scattered radiation is 26mR/hour. Therefore, lead screens cannot be used for protection. It is best to use the compartment operation method for fluoroscopy.
Dental X-ray machine: The X-ray tube head should have a protective layer of sufficient lead equivalent, and the X-ray tube head window should be equipped with an aluminum filter plate. In modern dental X-ray machines, the tip of the tube head is changed to a cylindrical light-collecting tube, which has a better effect of absorbing scattered rays than the tip of the tube head in the past.
Reduced exposure method: Under the principle of ensuring the quality of X-ray photos, small exposure fields with "high voltage, low current, and thick filter" should be used as much as possible. The best method to reduce exposure is to use a combination of intensifying screen and high-sensitivity X-ray film. When using the "dental intensifying screen" when shooting dental films, the exposure is much reduced, such as adding thick aluminum filter to reduce more. This can greatly reduce the amount of scattered radiation in the workplace and at the same time reduce the amount of X-rays received by the patient.
Time protection: The human body receives X-ray doses in proportion to the exposure time, which is cumulative. The longer the exposure time, the more X-rays received. Therefore, the exposure time should be minimized and avoided without affecting the work. Unnecessary exposure, reduce re-illumination rate.
Protection of the patient: The most effective method for filming is to reduce the exposure field and minimize the number and frequency of photos. If repeated filming or fluoroscopy is required, the interval between two examinations should be extended. Since fetuses, infants and children are very sensitive to X-rays, X-ray examinations should be done as little as possible or not.
