Dental radiography (part 1)

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.

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 quicker 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.

There are intraoral radiographic views (periapical view; bitewing view; occlusal view; full mouth series), extraoral radiographic views; panoramic films; computed tomography.

The periapical view is taken of both anterior and posterior teeth. The objective of this type of view is to capture the tip of the root on the film. This is often helpful in determining the cause of pain in a specific tooth, because it allows a dentist to visualize the tooth as well as the surrounding bone in their entirety. This view is often used to determine the need for endodontic therapy as well as to visualize the successful progression of endodontic therapy once it is initiated. It can be used in case of detection hyperdontia (supernumerary teeth) and impacted teeth.

The bitewing view is taken to visualize the crowns of the posterior teeth and the height of the alveolar bone in relation to the cementoenamel junctions, which are the demarcation lines on the teeth which separate tooth crown from tooth root. Routine bitewing radiographs are commonly used to examine for interdental caries and recurrent caries under existing restorations. When there is extensive bone loss, the films may be situated with their longer dimension in the vertical axis so as to better visualize their levels in relation to the teeth. Because bitewing views are taken from a more or less perpendicular angle to the buccal surface of the teeth, they more accurately exhibit the bone levels than do periapical views. Bitewings of the anterior teeth are not routinely taken. The name bitewing refers to a little tab of paper or plastic situated in the center of the X-ray film, which when bitten on, allows the film to hover so that it captures an even amount of maxillary and mandibular information.

Occlusal view

The occlusal view is indicated when there is a desire to reveal the skeletal or pathologic anatomy of either the floor of the mouth or the palate. The occlusal film, which is about three to four times the size of the film used to take a periapical or bitewing, is inserted into the mouth so as to entirely separate the maxillary and mandibular teeth, and the film is exposed either from under the chin or angled down from the top of the nose. Sometimes, it is placed in the inside of the cheek to confirm the presence of a sialolith in Stenson's duct, which carries saliva from the parotid gland. The occlusal view is not included in the standard full mouth series.

NOTES:

Bitewing view – довгофокусна рентгенографія (зйомка паралельними променями)

Ex.9. Translate the text " Dental radiography (part 1)" into your native language.

Ex. 10. Translate the following words and word-combinations into English:

Рентген; виявляти; стандартний; комплексний; прихований; злоякісний; доброякісний; оцінювання; проникати; зв’язки; зуби; м’яка тканина; інфекція; прикус; щічний; кістка; оточуючий; передній; плівка; піднебіння.

Ex. 11. Answer the following questions:

1.What is X-Ray? 2. How are dental radiographs commonly called? 3. Why do dentists use radiographs?.4. What is a radiographic image formed by? 4. What types of radiographic views have you learned from the previous text? 5.Why is periapical view taken? 6. Why is the occlusal view indicated? 7. How can you explaine the term “bitewing”? 8. Why is the bitewing view taken?

Ex. 12. Write out key sentences of the text " Dental radiography (part 1)".

Ex. 13. Compose the plan to the text " Dental radiography (part 1)".

Ex. 14. Speak on:

Intraoral radiographic view;

Periapical view;

Bitewing view;

Oclussal view;

Extraoral radiographic view.

Ex. 15. Translate the following sentences into English:

1.Періапікальні знімки роблять на передніх і задніх зубах. 2. Мета цього типу знімку - дістати корень на плівці. 3. Такий знімок часто використовується для визначення необхідності ендодонтичного лікування. 4. Він також може бути використаний у разі виявлення гіпердонтії. 5. Оклюзійні знімки роблять для виявлення патологій анатомії порожнини рота або піднебіння. 6. Оклюзійну плівку накладають таким чином, щоб повністю відокремити зуби верхньої і нижньої щелепи. 7. Назву «рентгеночуттєва плівка» відносять до маленької вкладки з паперу або пластику, розташованої у ротовій порожнині, за допомогою якої можна повністю бачити верхню та нижню щелепу.

Ex. 16. Read and memorize new words:

adjacent – прилеглий

mandibular - нижньощелепний

molar – моляр

premolar - примоляр

maxillary - верхньощелепний

canine – ікло

lateral incisor – бічний різець

malocclusion – малоклюзія (неправильний прикус)