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Introduction to Basic Concepts in Dental Radiography (AGD 730)

Presenter: Jan DeBell, CDA, EFDA, MS, BS


Dental x-rays (radiographs) are images that a dentist uses to evaluate one's oral health, identify problems, and risk for disease. The radiograph should be of sufficient diagnostic quality, and keep the radiation dosage as low as reasonably achievable (ALARA).

The course provides a comprehensive overview of how to take and process high quality radiographs, both film based and digital; promote radiation safety; mount and label exposed radiographs; identify and correct errors related to dental x-ray procedures; apply infection control techniques to dental x-ray procedures; expose and evaluate dental radiographs; and implement quality assurance procedures in dental radiology 


This completely revised edition has been authored by: 

Jan DeBell, CDA, EFDA, MS, BS
Jan DeBell has been in the dental assisting profession for 45 years. She has worked both as a clinical assistant and as an educator for the last 33 years. She taught Radiology for over 25 years and is recently retired from Front Range Community College as the Program Director for Dental Assisting. Ms. DeBell has a bachelor degree in career technological education and a master's in educational leadership from Colorado State University.


• Define ionizing and non-ionizing radiation and demonstrate an understanding of the types of radiation in the electromagnetic spectrum.
• Describe the components of matter, including atoms and their parts: electrons, protons, neutrons and nuclei.
• Demonstrate understanding of the properties and actions of matter: atom stability, bonding of atoms, ionization of atoms.
• Demonstrate an understanding of the difference between “traditional units of measurement” and Standard International Units (SIU) when measuring radiation.
• Define the concepts of density and contrast as they are used in dental radiography.
• Demonstrate understanding of the characteristics and actions of electricity, including: current (definitions and types), amperage (definition and types), milliamperage-second (definition), and voltage (definition and types), including kilovoltage.
• Describe the process of generating the radiation beam, from the time the machine is turned on to the emergence of the beam from the tubehead.
• Describe the generation of primary x-radiation.
• Describe interactions of x-radiation with matter to produce secondary radiation, and why this requires us to protect operator and patient during exposure to ionizing radiation.
• Demonstrate understanding of the following effects of radiation on cells and tissues: somatic and genetic effects and long- and short-term effects.
• Demonstrate understanding of how to control the x-ray beam, including: concepts of filtration, shielding, collimation, and distance.


• Define the risk/benefit ratio as applied to the prescription of radiographic images.
• Define and demonstrate an understanding of the ALADA concept.
• Demonstrate an understanding of the machine factors that influence radiation safety, including filtration, collimation and exposure technique. 
• Describe methods taken to protect the patient from excessive exposure to ionizing radiation, including the use of a protective apron/thyroid collar, different film speeds, use of receptor holders, film packet construction, and the importance of correct operator technique in exposing and processing radiographic images. 
• Describe methods taken to protect the operator from excessive exposure to ionizing radiation, including correct position, use of barriers, and radiation monitoring devices. 
• Identify the limits of radiation exposure (Maximum Permissible Dose or MPD) for the operator and the patient. 
• Describe methods taken to protect the community from excessive exposure to ionizing radiation, including licensing of facilities, restriction of who can prescribe radiographic images, training and certification of operators, and machine inspection and calibration.


• Identify and implement appropriate disinfection and set-up techniques during dental radiography procedures.
• Describe the technique of handwashing that should be used during dental radiography procedures.
• List infection control barriers to be used during dental radiography procedures, including gloves, masks, protective eyewear, gowns and equipment covers.
• Identify appropriate sterilization equipment, solutions and techniques used during dental radiography procedures.
• Discuss disposable equipment that can be used to enhance infection control during dental radiography procedures.
• Explain proper techniques for disposal of contaminated waste generated during dental radiography procedures.


• Evaluate the clinical record of the patient’s past radiation exposure.
• Evaluate the shape, position and condition of the patient’s oral structures.
• Describe methods to eliminate or reduce gagging during placement of intraoral image receptors.
• Assess the patient’s ability to cooperate with the requirements of the exposure technique.
• Evaluate the patient in terms of physical characteristics that may require a change in exposure time, such as age, weight and presence or absence of teeth.
• When exposing intraoral images, select appropriate film or receptor size depending on patient characteristics and the exposure technique indicated.
• Identify the diagnostic tasks for which the radiographic image will assist diagnosis.
• Assess whether the exposure technique conforms to the dentist’s policy.
• Identify and apply the five principles of ideal projection.
• Describe and indicate the usual uses of the following intraoral techniques of radiographic exposure: bisecting angle (BAT) and paralleling techniques (PT).
• Compare BAT and PT relative to their ability to fulfill the principles of ideal projection (shadow casting).
• Describe the process of exposure for each imaging technique, to include proper positioning of the loaded receptor holder, positioning of the patient, and alignment of the tubehead.
• Define the terms radiopaque and radiolucent, and give examples of structures and materials in each category.
• Describe which teeth and surrounding anatomical structures should be observed on each exposed radiograph in a full mouth radiographic survey. (FMX, FMS or CMS)
• Select and assemble accessories for radiographic techniques, including: XCP®, bitewing tabs, Stabe® bite block, cassettes, intensifying screens, and receptor holders, including Snap-A-Ray®, hemostats, and Uni-Bite®. 
• Select intra- or extraoral receptors on the radiographic exposure technique indicated. 
• Select appropriate film speed. 
• When exposing intraoral images, select the correct long axis (and convexity) orientation. 
• When exposing intraoral images, place the appropriate side of the receptor toward the source of radiation.
• When acquiring intraoral images, correctly place the imaging receptor into the holder. 
• When exposing extraoral radiographic images, select film size 8 x 10, 6 x 12, or 5 x 12 inches, depending on the technique indicated and the machine used. 
• When exposing extraoral radiographic images, load the film in the correct location. 
• When exposing conventional film-based extraoral images, affix the appropriate patient identification information. 
• When exposing conventional film-based extraoral images, assure that the film and screens are in continual contact.
• When exposing conventional film-based extraoral radiographs, position the cassette in a manner that permits total film exposure. 
• Describe proper methods of handling exposed and unexposed dental  film.


• Describe the preparation of radiographic solutions for manual, automatic and rapid processing.
• Describe how to process exposed intra- and extraoral radiographs using manual, automatic and rapid techniques.
• Describe how to clean and maintain processing equipment for manual, automatic and rapid techniques.


• Describe the types of mounts, including bitewing and full mouth (FMX).
• Identify the patient’s side, based on the identification bump on the radiograph.
• Match specific tooth views to specified mount windows.
• Identify information that should be placed on the radiographic mount.
• Describe the process for duplicating film-based radiographic images.
• Describe methods of filing and storing exposed and mounted radiographic images.


• Identify and correct errors related to improperly storing exposed and unexposed radiographic film.
• Identify and correct errors related to exposing intraoral radiographic images, including elongation, foreshortening, horizontal overlap, cone cutting, light image, dark image, film bending, herringbone effect, blank (clear) image, blurred image, superimposed image, double exposure, and saliva leak.
• Identify and correct errors related to exposing panoramic radiographic images, including incorrect patient positioning.
• Identify and correct errors related to radiographic processing, including spots on the film, fogging, light image, clear film, “cut-off” film, stains, discoloration, reticulation and air bubbles.
• Identify and correct errors due to improper film handling, including scratches and white or black lines, and static electricity artifacts.


• Describe how to implement quality assurance (QA) procedures in dental radiographic facilities, including the daily recording of solution temperatures, dates of solution changes, how and when to perform test film runs, how and when to clean and maintain equipment, knowledge of annual inspections, the importance of overseeing monitoring systems and the importance of the continuing education of operators.


• Identify the date that digital imaging was introduced to dentistry. • Describe the differences of analog radiography to digital imaging.
• Identify where the digital comes from in digital imaging.
• Identify the amount of reduction of absorbed radiation compared to both “D” and “F” film.
• Describe the principles of digital imaging.
• List the advantages and disadvantages of digital imaging.
• Describe the equipment needed for digital imaging.
• Describe the possible usage of image transmission of digital imaging and how the images are to be stored.


• List the more common applications for CBCT (cone beam computed tomography).
• Describe the difference in image capture between conventional CT (medical) and CBCT.
• Describe the differences in x-ray dose between conventional CT and CBCT.
• Describe the attributes of CBCT that make it more precise than conventional dental x-ray imaging modalities.


The ADAA has an obligation to disseminate knowledge in the field of dentistry.  Sponsorship of a continuing education program by the ADAA does not necessarily imply endorsement of a particular philosophy, product or technique.

The ADAA cautions participants taking this course on the hazards of using limited knowledge when integrating new techniques into their practices.

Credits earned upon completion of the course may be used to meet DANB’s Recertification Requirements.


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