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Dental Radiology
| Question | Answer |
|---|---|
| The radiographic density of silver restorations is? | metal substances such as amalgam restorations stop all x-rays that hit them, and become none of those rays reach the film , the film appears white. |
| Examples of substances in the oral cavity that are "radiolucent" are? | Substances that are much less dense than metal, such as muscle, blood, or other soft tissue, do not stop the passage of x-rays, and when radiographed, they result in blackened areas on the film. |
| Why is pulp tissue "radiolucent" on the film? | Pulp tissue is called radiolucent because the radiographed object allows the x-rays to pass through, or is lucent to the rays. |
| Caries is "radiolucent" on a radiograph because? | the most common dental conditions seen are dental caries, periodontal and periapical disease. These conditions destroy a portion of the normal tooth or jaw structure and therefore result in a more radiolucent shadow than is expected. |
| Destruction of the alveolar bone around the apex of a tooth is characteristic of what disease? | Periapical disease such as abscesses |
| Why is it an important asset and valuable to the dentist to develop high- quality radiographs and to process and mount films? | Radiographs should be free from distortion, have the correct density and contrast, and can be used for the detection of dental disease. Taking care in film placement, exposure, and processing. |
| Name 3 characteristics of the cathode | Negative (-) electrode consists of a tungsten filament in a focusing cup made of molybdenum ( a very hard silver metallic element. The purpose is to supply the electrons to generate x-rays. The hotter the filament, the more electrons are produced. The foc |
| Name 3 characteristics of the anode positive | (+) electrode is the target for electrons. Is a tungsten target in the larger copper stem. Copper conducts heat away from the target. Tungsten converts bombaring electrons into x-rays photons. 99% is absorbed, 1% exists as central ray. |
| Name the components of an atom | A central nucleus and orbiting electrons |
| What are atoms and molecules? | Atoms have outer shells that are filled with electrons. Molecules are formed by the combinations of 2 or more atoms. |
| What is energy ? | ability to do work |
| What is matter? | anything that occupies space and has form or shape |
| What is a photon and name 3 things that they do? | Bundless of pure energy . Strike the nucleus of an atom and the atom will be destroyed and release energy. The energy is released and transferred to the electrons. That is called a photo-electron and will have energy to ionize or strike other electrons. T |
| What is Ionization? what is an ion? | Ions are atoms that gain or lose an electron and become unstable. In the process called ionization electrons are removed from orbital shells of the electrically stable atoms through collisions with x-ray photons. |
| Name 3 characteristics of electromagnetic radiation? | Moves in straight lines at the speed of light (186,000 miles/sec.) They consist of energy only. They travel through space in the form of transverse waves. |
| List the steps involved in x-ray generation in a modern dental x-ray tube. | current travel from the control panel to the tubehead through electric wires in extension arm. Current travels through the step-down transformer is to decrease the voltage from 110 or 220 volts to 3 to 5 volts. 3 to 5 volts heat the tungsten filament in t |
| what is bremsstrahlen? | braking radiation |
| what is the purpose of the aluminium filter? | to remove the low-energy, long wavelength, least penetrating x-rays from the beam. |
| what is the purpose of the collimater? | it is made of lead and it restricts the size and shape of the x-ray beam and is constructed of 1/16inch lead |
| why is ionization important in radiation biology? | because you need to know that it is harmful and produces biologic changes in living tissues |
| what is genetic effects? | Genetic make-up all the reproductive cells such as the ova and sperm |
| what is the somatic effect | somatic make up all the cells except the reproductive cells |
| what is milliamperage and name 3 factors of mA. | is a measure of electric current that passes through the tungsten filament. it controls the amount or quantity of electrons that are produced. the higher the mA the greater the amount of radiation. The mA is set at 10 or 15 mA. |
| the higher the milliamperage the greater the blank of radiation | amount |
| what is kilovoltage and name 3 factors of kVp. | is used to control the quality or penetrating power of the x-ray beam. the greater the penetration power the less exposure time is required, therefore less radiation to the patient. the quicker the radiation goes through the tissues, the greater the quali |
| the higher the kilovoltage, the greater the blank power of the x-ray beam. | penetration |
| what is density and name 5 things that control density? | density is the overall blackness or darkness of a film. 1. distance from the x-ray tube to the patient 2. mA milliamperage setting 3. developing time 4. body size of the patient 5. kVp kilovoltage |
| describe contrast. | shades from black to white with multiple shades of gray (gray scales) |
| what would you do if you wanted more contrast on a film? | lower the kVp |
| what would you do if you wanted less contrast on a film? | higher the kVp |
| name the 3 characteristics of a radiograph beam | quality, quantity, and intensity of the x-ray beam. |
| what is radiolucent? | light or white areas on a radiograph |
| what is sharpness? | how well the radiograph reproduces the fine details pr distinct outlines of an object. and is influenced by 1 focal spot=small focal results in a sharper image 2 film composition= fast film speed results in less sharp detail because of large crystals size |
| what is distortion? | refers to the disproportional change in the size of images on radiograph that is caused by excessive or insufficient vertical angulations elongated or foreshortened |
| what is magnification? | refers to the proportional enlargement pf a radiographic image scissors |
| periapical= | shows the entire tooth from occlusal surface or incisal edge to about 2 to 3mm beyond the apex to show the peroapical bone. |
| horizontal bitewing= | used for detecting interproximal decay, peridontal disease, recurrent decay, and the fit of metallic fillings or crowns. |
| panoramic = | radiogrpah that shows the upper and lower jaw on one film |
| occlusal= | radiograph that shows the upper or lower jaw on one film |
| cephalometric= | a radiograph that shows the bony and soft tissue areas of the facial profile that shows the bony and soft tissue areas of the facial profile. |
| name the different sizes of film and what are the 5 basic rules? | also known as the extension cone parelleling (XCP) right angle, or long cone technique. 1. film placement= needs to cover all the teeth 2. film position=film to be parallel to the long axis of the tooth 3. vertical angulations= central ray must be perp |
| what is the recommended PID for the parellelling technique? | 16inch |
| what is the bisecting technique and name 5 reasons why it is different than the paralleling technique? | based on the geometric principle of equally dividing a triangle. parallel you move film away from teeth. bisecting angle is formed by the long axis of the teeth and bisected into 2 parts. Disadvantage is distortion. Used on pt's. when you cant do parallel |
| know the difference between radiolucent and radiopaque. | Radiolucent is dark areas and radiopaque is light or white areas on a film. |
| know the difference between shorter and longer wavelengths. | short wavelengths with high frequency=more energy long wave length with low frequency=less energy |
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Dgalin985
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