Radiology Chapter Recall Questions

What is the difference between a bitewing and a periapical image?

A bitewing shows only the crowns, alveolar ridge, and a small portion of the root. The periapical shows the entire length of the tooth, including the apex and surrounding areas.

What is the definition of a diagnostic-quality image?

A diagnostic-quality image is one that has been properly placed, exposed, and processed.

How does the use of film holders protect the patient from unnecessary radiation?

A film holder keeps the patient's hands and fingers from being exposed to x-radiation.

What is a focal trough?

A focal trough is an imaginary horseshoe-shaped area used for jaw placement during panoramic exposures.

Why are the reference radiograph and the stepwedge used?

A reference radiograph and the stepwedge are used to check radiographic densities and contrast.

What is a safelight?

A safelight is a low-intensity light composed of long wavelengths in the red-orange spectrum.

Which staff members have to be aware of the quality administration program?

All staff members have to be aware of the quality administration program.

What is an intensifying screen?

An intensifying screen converts radiographic energy into visible light.

Why is the exposure sequence especially important when one is taking x-rays on a patient with a severe gag reflex?

As patients are most likely to gag on posterior films, it is best to begin in the anterior areas.

What type of film or sensor holders can be used in the bisecting technique?

BAI, EeZee-Grip, and Stabe are film or sensor holders that can be used in the bisecting technique.

What is the purpose of a beam alignment device?

Beam alignment devices assist in the positioning of the position indicator device in relation to the tooth and film.

What types of film might be needed to supplement a panoramic image? Why?

Bitewing and selected periapicals are needed to supplement a panoramic image because of the lack of detail in a panoramic film.

What is the purpose of bitewing images?

Bitewing images are used to detect interproximal caries and evaluate crestal bone.

Who was the first person to make practical use of x-rays in dentistry?

C. Edmund Kells was the first person to make practical use of x-rays in dentistry.

What unique infection control problems occur in dental imaging?

Constant movement by the operator—from the oral cavity to the exposure controls outside the operatory, to the darkroom, and finally to film mounting—increases the risk for exposing others to infectious diseases.

Why is a CBCT image better than a periapical image?

Conventional images (such as periapical and bitewing) are only in two dimensions (2D).

What is meant by density on a dental radiograph?

Density is the overall darkness of a processed radiograph controlled by milliamperage and time.

What two errors occur when the vertical angulation is incorrect?

Elongation and foreshortening can occur when the vertical angulation is incorrect.

What changes must be made in exposure factors when one is exposing dental images on a pediatric patient?

Exposure factors (milliamperage, kilovoltage, exposure time) must be reduced because of the smaller size of the pedi atric patient.

When are extraoral radiographs needed?

Extraoral radiographs are taken when large areas of the skull or jaw must be examined.

What are the two types of extraoral film cassettes?

Film cassettes may be either rigid or flexible.

What are the five steps in processing dental radiographs?

Film processing involves (1) developing, (2) rinsing, (3) fixing, (4) washing, and (5) drying.

What is one of the most critical areas in a quality control program?

Film processing is one of the most critical areas in a quality control program and must be monitored daily.

What size of film is recommended for a pediatric patient with all primary dentition?

Film size #0 is recommended for a pediatric patient with all primary dentition.

For partially edentulous patients, how can you modify the technique for using a bite-block?

For partially edentulous patients, you can modify the technique by placing cotton rolls where the bite-block would be placed.

Which projection should be the first for posterior exposures?

For the patient's comfort, the premolar view is the first mandibular exposure.

What is meant by genetic effects of radiation?

Genetic effects of radiation are those that are passed on to future generations.

In digital radiography, what replaces the intraoral film?

In digital radiography the sensor replaces the intraoral film.

Which of the digital techniques requires scanning of image receptors?

In phosphor storage imaging (indirect digital imaging), a scanner is required to "read" the information stored on the phosphor storage plate (PSP).

In the bisecting technique, how is the film or sensor placed in relation to the teeth?

In the bisecting technique, the image receptor is placed close to the crowns of the teeth to be x-rayed and extends at an angle into the palate or the floor of the mouth. The image receptor should extend beyond the incisal or occlusal aspect of the teeth by about 1/8 inch.

What type of consent is necessary before a patient is exposed for dental images?

Informed consent is necessary before a patient is exposed for dental images.

What is the name of the process that results in the harmful effects of x-rays?

Ionization causes the harmful effects of x-rays.

What is ionization?

Ionization is the process by which electrons are removed from electrically stable atoms through collisions with x-ray photons.

Why is it important for the dental assistant to recognize anatomic landmarks?

It is important for the dental assistant to recognize anatomic landmarks because they are useful in mounting radiographs.

When might it be necessary to duplicate x-rays?

It might be necessary to duplicate radiographs for the insurance company or for referral of patients to a specialist or another dental office.

Which exposure factor controls contrast?

Kilovoltage controls contrast.

What precautions should be taken when one is handling the lead apron?

Lead aprons must not be folded when stored, as folding can eventually lead to cracks in the lead.

What is the major advantage of automatic film processing?

Less time required for processing is the major advantage of automatic film processing.

Are manual processing solutions and automatic processing solutions interchangeable?

Manual processing solutions and automatic processing solutions are not interchangeable.

Should you use a film cassette that has scratches?

No, you should not use a film cassette that has scratches.

What error occurs when the horizontal angulation is incorrect?

Overlapping of the contacts occurs when the horizontal angulation is incorrect.

What physical disabilities may affect dental patients?

Patients may have vision, hearing, and mobility disabilities.

How often should processing solutions be replenished?

Processing solutions should be replenished daily.

What is the purpose of a quality administration program?

Quality administration deals with the management of the quality assurance program.

What is meant by quality assurance?

Quality assurance is a way of ensuring that high-quality diagnostic radiographs are produced.

What are quality control tests?

Quality control tests are specific tests used to monitor dental radiographic equipment, supplies, and film processing.

What precautions should be taken when storing x-ray film?

Radiographic film should be stored away from light, heat, moisture, chemicals, and scatter radiation.

Describe the difference between radiopaque and radiolucent.

Radiopaque refers to a white or light appearance of a structure on a processed radiograph. Radiolucent refers to a dark appearance of a structure on a processed radiograph.

Why is it important to avoid retakes?

Retakes expose the patient to unnecessary radiation.

What number film is used for adult radiographs?

Size #2 film is used for adult radiographs.

What size film is used for adults in the occlusal technique?

Size #4 film is used for adults in the occlusal technique.

What size film is used for occlusal radiographs?

Size #4 film is used for occlusal radiographs.

Give examples of structures that appear radiolucent on a radiograph.

Structures that appear radiolucent on a radiograph are air spaces, soft tissues, abscesses, tooth decay, and dental pulp.

Give examples of structures that appear radiopaque on a radiograph.

Structures that appear radiopaque on a radiograph are tooth enamel, dense areas of bone, and metal restorations.

What surfaces must be covered with barriers?

Surfaces that are not easily cleaned and disinfected must be covered with barriers.

When mounting radiographs, what is the ADA's recommendation concerning placement of the raised dot?

The ADA recommends mounting radiographs with the dot facing up.

What federal act requires persons who take radiographs to be trained and certified?

The Consumer-Patient Radiation Health and Safety Act requires persons who take radiographs to be trained and certified.

What is the purpose of the aluminum filter?

The aluminum filter is used to remove the low-energy, long-wavelength rays.

Name the positive electrode inside the x-ray tube.

The anode is the positive electrode inside the x-ray tube.

Name the negative electrode inside the x-ray tube.

The cathode is the negative electrode inside the x-ray tube.

What is the purpose of the collimator?

The collimator is used to restrict the size of the primary beam.

What does the control panel contain?

The control panel of an x-ray unit contains the master switch and two indicator lights, exposure button, milliamperage (mA) selector, and kilovoltage peak (kVp) selector.

Who is the legal owner of a patient's dental images?

The dentist is the legal owner of a patient's dental images.

What precautions must be taken when films are transported to the darkroom?

The disposable container should never be touched with gloved hands. Only after your gloves have been removed, your hands washed and dried, the patient dismissed, and the area cleaned and disinfected should the container with contaminated films be carried to the darkroom.

How can you find the expiration date of a package?

The expiration date of a package of radiographic film is on the outside of the box.

What are the five components of intraoral film?

The five components of intraoral film are: (1) a film base made of clear cellulose acetate; (2) a thin adhesive layer that attaches the emulsion to the film base; (3) a gelatin that suspends the emulsion of microscopic silver crystals over the film base; (4) silver halide crystals that absorb radiation; (5) a thin transparent coating that protects the emulsion surface.

What horizontal angulation should be used for bitewing images?

The horizontal angulation should be +10 degrees for bitewing images.

What is a latent image?

The image on the film before processing is the latent image.

What is the name of the time period between x-ray exposure and the appearance of symptoms?

The latent period is the time between x-ray exposure and the appearance of symptoms.

How often should the levels of solution in the automatic processor be checked?

The levels of solution in the automatic processor are checked daily.

How does extraoral film react differently from intraoral film?

The light from the screen exposes the extraoral film; the intraoral film is exposed directly by radiation.

Which is the most widely used form of processing solution?

The liquid concentrate is the most widely used form of processing solution.

What is the maximum permissible dose of radiation for occupationally exposed persons?

The maximum permissible dose of radiation for occupationally exposed persons is 5.0 rem per year.

What is the minimum distance between the safelight and the working area?

The minimum distance between the safelight and the working area is 4 feet.

What personal protective equipment should the operator wear while exposing radiographs?

The minimum personal protective equipment that the operator should wear while exposing radiographs is a gown and gloves. Masks and eyewear are optional unless blood or other body fluids may spatter.

What is the most effective measure in reducing a patient's exposure to radiation?

The most effective measure in reducing patient exposure is the use of fast-speed film.

When are occlusal radiographs indicated?

The occlusal technique is used when large areas of the maxilla or mandible must be radiographed.

What is the optimum temperature for the water in the manual processing tanks?

The optimum temperature for the water in the manual processing tanks is 68º F.

When should the packages that contain positioning instruments be opened?

The packages that contain positioning instruments should be opened in front of the patient.

Why is it not recommended to have the patient hold the film or sensor during exposure?

The patient's hand and finger receives unnecessary radiation when holding the film or sensor during exposure.

What are the primary components of a dental x-ray machine?

The primary components of a dental x-ray machine are the tubehead, the extension arm, and the control panel.

What is the primary difference between a film holder and a digital sensor holder?

The primary difference between film holders and digital sensor holders is in the size and shape of the holder.

What is the purpose of the coin test?

The purpose of the coin test is to check the safelight.

What are the three characteristics of the x-ray beam?

The three characteristics of the x-ray beam are quality, quantity, and intensity.

Name the three types of radiation?

The three types of radiation are primary, secondary, and scatter.

Name the two systems of radiation measurement.

The traditional, or standard, system and the Systeme Internationale (SI) are used to measure radiation.

What are the two techniques that can be used for exposing images?

The two techniques for exposing images are the paralleling and bisecting techniques.

How can you tell which side of the film is placed toward the tube?

The white side of the film is placed toward the tube.

What are the two fundamental techniques for intraoral digital radiography?

Two fundamental techniques used for intraoral digital radiography are direct digital imaging and indirect digital imaging.

Under what circumstance would you hold a film sensor for a patient?

Under no circumstances should you hold a film sensor for a patient.

Under state laws, who is allowed to prescribe dental images?

Under state laws, a dentist is allowed to prescribe dental images.

Why is an exposure sequence important?

Using an exposure sequence is important so that areas of the mouth are not missed or repeated.

What type of gloves should be worn while one is disinfecting the radiography operatory?

Utility gloves should be worn while disinfecting the radiography operatory.

When exposing images on a pediatric patient, how can you best describe the tubehead for the patient?

When exposing images on a pediatric patient, you can describe the tubehead as a "camera."

When exposing images, in which area of the mouth should you begin?

When exposing images, you should begin in the maxillary anterior area.

How can you tell when the fixer loses its strength?

When films take longer to "clear," the fixer is losing its strength.

Who discovered x-rays?

Wilhelm Conrad Roentgen discovered x-rays.

What precautions should be taken when one is handling contaminated film or PSPs?

You should always wear gloves while handling contaminated film or PSPs. After the exposed receptor is removed from the patient's mouth, wipe saliva off using a dry 2 x 2-inch gauze sponge or paper towel. Once the film or PSP envelope is dry, place it into a disposable paper cup labeled with the patient's name. If the PSPs are not going to be immediately scanned, while gloved, remove from the sealed envelope, open the barrier envelopes, and place the PSPs into a black transfer box.

When should you check a box of film for freshness?

You should check the film for freshness each time you open a box of new film.