Dental radiography

Dental radiographs are commonly called X-rays. Dentists use radiographs for many reasons: to find hidden dental structures, malignant or benign masses, bone loss, and cavities. Dental radiographs are commonly called X-rays. Dentists use radiographs for many reasons: to find hidden dental structures, malignant or benign masses, bone loss, and cavities. A radiographic image is formed by a controlled burst of X-ray radiation which penetrates oral structures at different levels, depending on varying anatomical densities, before striking the film or sensor. Teeth appear lighter because less radiation penetrates them to reach the film. Dental caries, infections and other changes in the bone density, and the periodontal ligament, appear darker because X-rays readily penetrate these less dense structures. Dental restorations (fillings, crowns) may appear lighter or darker, depending on the density of the material. The dosage of X-ray radiation received by a dental patient is typically small (around 0.150 mSv for a full mouth series, according to the American Dental Association website), equivalent to a few days' worth of background environmental radiation exposure, or similar to the dose received during a cross-country airplane flight (concentrated into one short burst aimed at a small area). Incidental exposure is further reduced by the use of a lead shield, lead apron, sometimes with a lead thyroid collar. Technician exposure is reduced by stepping out of the room, or behind adequate shielding material, when the X-ray source is activated. Once photographic film has been exposed to X-ray radiation, it needs to be developed, traditionally using a process where the film is exposed to a series of chemicals in a dark room, as the films are sensitive to normal light. This can be a time-consuming process, and incorrect exposures or mistakes in the development process can necessitate retakes, exposing the patient to additional radiation. Digital X-rays, which replace the film with an electronic sensor, address some of these issues, and are becoming widely used in dentistry as the technology evolves. They may require less radiation and are processed much more quickly than conventional radiographic films, often instantly viewable on a computer. However digital sensors are extremely costly and have historically had poor resolution, though this is much improved in modern sensors. It is possible for both tooth decay and periodontal disease to be missed during a clinical exam, and radiographic evaluation of the dental and periodontal tissues is a critical segment of the comprehensive oral examination. The photographic montage at right depicts a situation in which extensive decay had been overlooked by a number of dentists prior to radiographic evaluation. There are numerous risks associated with the taking of dental radiographs, even though the dose to the patient is minimal, the collective dose needs to be considered in this context as well. Therefore, it is incumbent on the operator and prescriber to be aware of their responsibilities when it comes to exposing a patient to ionizing radiation. The United Kingdom has 2 sets of regulations related to the taking of x-rays. These are the Ionizing Radiations Regulations 2017 and IRMER (Ionizing Radiations Medical Exposures Regulations) 2018. IRR17 principally relates to the protection of workers and the public, along with the equipment standards. IRMER18 is specific for patient protection. These regulations replace the previous versions which were being followed for many years (IRR99 and IRMER2000). This change has come primarily due to Basic Safety Standards Directive 2013 (BSSD; also known as European Council Directive 2013/59/Euratom), which all European Union member states are legally required to transpose into their national laws by 2018. The above regulations are specific to the United Kingdom. Whereas the EU and USA are principally governed by the directive 2013/59/Eurotam and The Federal Guidance For Radiation Protection respectively. The goal of all these standards, including others governing other countries, is primarily to protect the patient, operators, maintain safe equipment and ensure quality assurance. The UK’s Health and Safety Executive (HSE) has also published an accompanying Approved Code of Practice (ACoP) and associated guidance, which gives practical advise on how to comply with the law. Following the ACoP is not obligatory. However, compliance with it can prove very beneficial for the legal person if they were to face any negligence or lack of compliance to the law issues, as it will confirm that the said legal person has been implementing good practice. With IRR17 and IRMER18, there are certain key roles and responsibilities that need to be carried out by a designated person. One person may carry out more than one role. The person or body corporate with the legal responsibility in respect to every dental X-ray and every item of auxiliary equipment associated with radiation safety is known as The Legal Person.