For each description of a radiograph’s appearance listed, select the most closely linked error. Each answer will only be used once. Appearance Error 1. Clear A. Film was developed in weak developer 2. Light B. Film was exposed to white light 3. Light film with “tire tracks” C. Film was placed backward 4. Fogged D. Film was developed in a dark room with a crack in the safelight cover 5. Black E. Film was not exposed to x-rays

1. Clear E. Film was not exposed to x-rays 2. Light A. Film was developed in weak developer 3. Light film with “tire tracks” C. Film was placed backward 4. Fogged D. Film was developed in a dark room with a crack in the safelight cover 5. Black B. Film was exposed to white light

Final Flashcards by Big Red

The smaller the silver halide crystals in the emulsion of an intraoral film, the faster the film speed.

Faster film speed reduces radiation exposure to the patient.

A. Both statements are true.

B Both statements are false.

C The first statement is true, and the second statement is false.

D The first statement is false, and the second statement is true.

D. The first statement is false, and the second statement is true.

How well did you know this?

Not at all

Perfectly

Which of the following statements BEST describes the anomaly in the image shown below?

A Foreshortening of the root, vertical angle too great

B Foreshortening of the root, vertical angle not enough

C Incomplete apical development of the root

D Internal resorption of the root

E External resorption of the root

E. External resorption of the root

How well did you know this?

Not at all

Perfectly

A periapical (PA) image is needed on the maxillary left premolar area. The patient presents with a large maxillary torus. Using the paralleling, or right-angle, technique, the image receptor film or sensor is to be placed

A distal to the maxillary premolar area.

B mesial to the maxillary premolar area.

C as close to the maxillary left premolar as possible.

D as far from the maxillary left premolar as possible.

D. as far from the maxillary left premolar as possible.

How well did you know this?

Not at all

Perfectly

A periapical image of the maxillary right molar area is needed, but patient has a shallow palate, and the first image taken misses the apices of the teeth. To correct this error, using the paralleling technique, an acceptable image can be obtained by moving the PID in a:

A 20-degree difference in the horizontal angulation toward the mesial surfaces.

B 20-degree difference in the horizontal angulation toward the distal surfaces.

C positive 20-degree difference in the vertical angulation.

D negative 20-degree difference in the vertical angulation.

E direction in which the central ray is perpendicular to the image receptor.

C. +20-degree difference in the vertical angulation.

How well did you know this?

Not at all

Perfectly

A radiographic image will have increased density if the operator:

A increases the kVp.

B decreases the kVp.

C decreases the milliampere (mA).

D increases the distance of the x-ray source to the image receptor.

A. increases the kVp.

How well did you know this?

Not at all

Perfectly

Absorption:

Process of transferring energy of x-rays to atoms of material through which the x-ray beam passes

The beam of x-rays passing through matter is

weakened and gradually disappears.

(tooth absorbs energy = turns white)

How well did you know this?

Not at all

Perfectly

According to the SLOB rule, the position of objects can be determined if the tube head is shifted in a mesial direction. The lingual object moves distally, and the buccal object moves mesially.

A. Both statements are true.

B Both statements are false.

C The first statement is true, and the second statement is false.

D The first statement is false, and the second statement is true.

B. Both statements are false.

How well did you know this?

Not at all

Perfectly

All of the following are examples of radiosensitive cells EXCEPT one.

Which one is the EXCEPTION?

A. Cells with higher metabolism

B Cells with high mitotic activity

C Older, mature cells

D Primitive, nonspecialized cells

C. Older, mature cells

How well did you know this?

Not at all

Perfectly

All of the following decrease radiation exposure to the patient EXCEPT one. Which one is the EXCEPTION?

A Thyroid collar

B F-speed film in place of D-speed film

C 8-inch PID in place of 16-inch PID

D Rectangular PID in place of round PID

E Collimator

C. 8-inch PID in place of 16-inch PID

How well did you know this?

Not at all

Perfectly

All of the following factors increase image sharpness EXCEPT one. Which one is the EXCEPTION?

A Slower film speed

B Small focal spot

C Decreased penumbra

D Movement

D. Movement

How well did you know this?

Not at all

Perfectly

All of the following phrases are consistent with the paralleling technique

EXCEPT one. Which one is the EXCEPTION?

A. A short PID is used.

B. It is the preferred method for taking radiographs.

C. The film is placed parallel to the long axis of the tooth.

D. The central ray is directed perpendicular to the tooth and the image receptor.

E. It produces images with the least magnification and dimensional distortion.

A. A short PID is used.

How well did you know this?

Not at all

Perfectly

An x-ray beam has a half-value layer (HVL) of 6 mm. How many millimeters of aluminum are required to reduce the x-ray beam intensity by half?

A 2 mm

B 3 mm

C 6 mm

D 12 mm

C. 6 mm

How well did you know this?

Not at all

Perfectly

Characteristic radiation:

(C)

Produced when a high-speed electron from the tube filament collides with an orbiting K-shell electron of the tungsten target.

How well did you know this?

Not at all

Perfectly

Coherent scattering:

(B)

Incoming x-ray photon interacts with the electron by causing the electron to vibrate at the same frequency as the incoming x-ray photon.

Accounts for about 8% of the interactions of matter with the dental x-ray beam

How well did you know this?

Not at all

Perfectly

Compton scattering:

Similar to the photoelectric effect

Incoming x-ray photon collides with an orbital electron and ejects it. But, only a part of the x-ray energy is transferred to the electron, and a new, weaker x-ray photon is formed and scattered in a new direction.

Accounts for about 60% of the interactions of matter with the dental x-ray beam.

How well did you know this?

Not at all

Perfectly

Cone cutting has occurred on the coronal portion of a mandibular anterior PA image. The operator will correct this error by:

A. moving the image receptor more superiorly.

B moving the image receptor more inferiorly.

C moving the PID to completely cover the image receptor.

D adding more solution to the developer.

E adding more solution to the fixer.

C. moving the PID to completely cover the image receptor.

How well did you know this?

Not at all

Perfectly

Considering exposure time during the production of x-rays, how many impulses are equivalent to 1⁄4 second?

A 1

B 6

C 15

D 30

E 240

C. 15

There are 60 impulses in a second, so to calculate impulses, multiply

60 x 1⁄4 second = 15 impulses

How well did you know this?

Not at all

Perfectly

Erythema, nausea, diarrhea, hemorrhage, and loss of hair are

signs and symptoms seen with

A. chronic radiation exposure.

B acute radiation exposure.

C stochastic effects of radiation exposure.

D nonstochastic effects of radiation exposure.

E A and C

F B and D

B. acute radiation exposure.

and

D. nonstochastic effects of radiation exposure.

How well did you know this?

Not at all

Perfectly

Failing to follow radiation exposure patient guidelines would put a fetus at greatest risk in which trimester?

A First trimester

B Second trimester

C Third trimester

D Risk during all trimesters is equal

E There is no risk

A. First trimester

How well did you know this?

Not at all

Perfectly

For each description of a radiograph’s appearance listed, select the most closely linked error. Each answer will only be used once.

Appearance Error

Clear A. Film was developed in weak developer
Light B. Film was exposed to white light
Light film with “tire tracks” C. Film was placed backward
Fogged D. Film was developed in a dark room with a crack in the safelight cover
Black E. Film was not exposed to x-rays

Clear E. Film was not exposed to x-rays
Light A. Film was developed in weak developer
Light film with “tire tracks” C. Film was placed backward
Fogged D. Film was developed in a dark room with a crack in the safelight cover
Black B. Film was exposed to white light

How well did you know this?

Not at all

Perfectly

From the following list, select examples of stochastic effects of radiation exposure. (Select all that apply.)

A. Erythema

B Cancer

C Hair loss

D Genetic mutations

E Decreased fertility

B. Cancer

D. Genetic mutations

How well did you know this?

Not at all

Perfectly

From the following list, select the three elements used in the x-ray tube.

A Bromine

B Copper

C Iron

D. molybdenum (focusing cup)

E Nickel

F Silver

G Tungsten

B. Copper

D molybdenum (focusing cup)

G Tungsten

How well did you know this?

Not at all

Perfectly

From the following list, select the three statements

associated with digital imaging.

A. Sensors cannot be sterilized.

B A digital image is a two-dimensional representation of a 3-D object.

C Exposure times are 50% to 90% more than in traditional radiography.

D Digital imaging must be wired to function correctly.

E Assembled pictorial information with each gray value is

assigned a digit in binary code.

A. Sensors cannot be sterilized.

B. A digital image is a two-dimensional representation of a 3-D object.

E. Assembled pictorial information with each gray value is assigned a digit in binary code.

How well did you know this?

Not at all

Perfectly

General/bremsstrahlung radiation:

Produced when high-speed electrons are stopped or slowed down by the tungsten atoms of the dental x-ray tube.

How well did you know this?

Not at all

Perfectly

Identify # 10

X-Rays

Identify # 11

Port

Identify # 12

Oil

Identify # 14

Cathode (-)

Identify #1

Tube head

Identify #13

Copper stem

Identify #2

Low voltage transformer

Identify #3

Primary beam

Identify #4

High voltage transformer

Identify #5

Window

Identify #6

Collimator

Identify #7

Central ray

Identify #8

Filter

Identify #9

PID

Identify the **almond-shaped radiolucent** area in the image shown. A Infraorbital foramen B Nasal cavity C Median palatal suture D Maxillary sinus E Incisive foramen

E. **Incisive foramen**

Identify the structure to which the **arrows are pointing** in the image shown. A Maxillary sinus B Maxillary tuberosity C Genial tubercles D Zygoma

D. **Zygoma**

In a **darkroom**, the **correct lighting and distance** from the **working surface** should be A. a 60-watt bulb placed 6 feet away. B. a 75-watt bulb placed 6 feet away. C. a 7.5-watt bulb place 6 feet away. D. a 30-watt bulb placed 8 feet away.

C. a **7.5-watt** bulb place **6 feet away.**

In a dental x-ray tube, the **kinetic energy** of electrons is **converted** to **electromagnetic energy** by the formation of:

**General or bremsstrahlung radiation** German for “braking” Characteristic radiation

In the **molar bitewing** image, the **error** that will occur as a **result of the PID positioning** will be **distal overlap**. Distal overlap is **corrected by repositioning** the **horizontal angulation** of the PID **more mesiodistally.** A. Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

D. The **first** statement is **false**, and the **second** statement is **true.**

In which **anomaly** is the **cementum** of **two adjacent teeth joined together**? A Concrescence B Fusion C Gemination D Hypercementosis

A. **Concrescence**

Interaction of X-rays with Matter:

**Four possibilities:** 1. No interaction 2. Coherent scattering 3. Photoelectric effect 4. Compton effect

No interaction: ## Footnote **(A)**

X-ray photon can pass through an atom **unchanged and no interaction** occurs. In dental radiography, about 9% of the x-rays pass through the patient’s tissues without interaction.

**Order the steps** for the **manual processing** of x-ray **films**. Match each letter with its proper sequence number. **Sequence Number Steps** 1. _____ A. Rinsing in water for 30 seconds 2. _____ B. Washing in water for 20 minutes 3. _____ C. Developing 4. _____ D. Fixing 5. _____ E. Drying

1. **Developing** 2. **Rinsing in water for 30 seconds** 3. **Fixing** 4. **Washing in water for 20 minutes** 5. **Drying**

**Order the steps** in the **production of x-radiation**. Match each letter with its proper sequence number. 1. _____ A. Electrons travel across to the anode when the high voltage circuit is activated. 2. _____ B. Thermionic emission occurs. 3. _____ C. 110 or 220 line voltage is reduced to 3 to 5 volts. 4. _____ D. Kinetic energy is converted to x-ray energy and heat.

1. C. **110 or 220** line **voltage** is **reduced to 3 to 5 volts.** 2. B. **Thermionic emission occurs.** 3. A. **Electrons travel across to the anode** when the **high voltage circuit is activated.** 4. D. **Kinetic energy** is **converted to x-ray energy and heat.**

Photoelectric effect: Incoming x-ray photon **collides with an orbital electron** and imparts **electromagnetic energy** to the electron in the form of **kinetic energy** causing **electron to fly from its orbit, creating an ion pair.**

**All-or-nothing energy loss** High-speed electron (called a **photoelectron**) **knocks other electrons from the orbits of other atoms** (forming secondary ion pairs) until all its energy is used up. Accounts for about **30%** of the interactions of matter with the dental x-ray beam

Primary radiation:

General and/or characteristic radiation generated at a **target** inside x-ray tube head Refers to the **useful beam**, or those x-rays generated for the **purpose of making a radiographic image**

**Radiation exposure** is **not of concern** when it occurs in **small doses**. The **cumulative effect of radiation exposure** may lead to health problems **such as cancer.** A. Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

D. The **first** statement is **false**, and the **second** statement is **true.**

**Radiation may damage cells** indirectly by **damaging the cell nucleus.** Direct **cellular damage** occurs when **ionization** causes **radiolysis of water** producing **hydrogen peroxide.** A. Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

B. **Both** statements are **false.**

**Radiography** provides the **most accurate measurements** for the **assessment of periodontal disease** and its **progression**. This is because radiographs **record both historical and current disease activity.** A. Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

B. **Both statements are false.**

From the following list, **select two structures that appear radiolucent** on a radiographic image. A Nasal septum B Lateral or canine fossa C Anterior nasal spine D Inferior nasal conchae E Nutrient canals

B **Lateral or canine fossa** E **Nutrient canals**

Scatter radiation:

Form of secondary radiation Results when x-rays are **deflected in all directions** as a result of interaction with matter Not useful **Can cause unnecessary additional exposure to patient tissues and to the careless operator** who does not follow safety protocols **Lead apron + lead wall = no scatter radiation**

Secondary radiation:

Formed as a result of primary radiation striking and interacting with matter Not as penetrating as primary radiation **Not useful in the production of a radiographic image** **Can contribute to a lowered contrast, poor quality image**

The **coronoid process** of the **mandible** appears as a **triangular-shaped** **radiopacity.** This marked **prominence of bone** found on the **anterior ramus** of the **mandible** is **not seen** on a **mandibular** **periapical** radiograph. A. Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

A. **Both statements are true.**

The **device that restricts t**he **size of the x-ray beam** is called a/an A dosimeter. B aluminum filter. C collimator. D focusing cup. E inherent filtration.

C. **collimator.**

The **error** that will occur to the **premolar bitewing** image as a **result of the PID positioning** will be A. unequal distribution of maxillary and mandibular teeth. There will be more coverage of maxillary teeth and fewer mandibular teeth. B unequal distribution of maxillary and mandibular teeth. There will be more coverage of mandibular teeth and fewer maxillary teeth. C distal overlap. D mesial overlap.

B. **unequal distribution of maxillary and mandibular teeth.** There will be **more coverage** of **mandibular teeth** and **fewer maxillary teeth.**

The **kVp setting** is the **only exposure factor** that has **direct influence** on the **contrast** of a dental radiograph. **High kVp settings** result in **high contrast images.** A. Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

C The **first** statement is **true**, and the **second** statement is **false.**

The **mental fossa** is **visible** in which radiographic image? A Maxillary premolar B Maxillary canine C Mandibular central D Mandibular premolar

C. **Mandibular central**

The **radiographic appearance** of the **zygomatic process of the maxilla** appears as a **J-shaped or U-shaped radiopacity** located **superior to the maxillary first molar** region. The visibility of the **zygomatic process of the maxilla** on the image is a result of utilization of the **bisecting technique.** A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

C. The **first** statement is **true**, and the **second** statement is **false**

The **tube head** is a component of the **x-ray machine** that **helps limit radiation** to the patient in **all of the following functions** EXCEPT one. Which one is the **EXCEPTION**? A. Inherent filtration within glass tube, insulating oil, and tube head B Added aluminum disk filtration C Production of both long-wavelength and short-wavelength xrays D Collimation with lead disk placed in the pathway of the x-ray beam E Rectangular collimated PID

C. Production of **both long-wavelength** ## Footnote **and** **short-wavelength Xrays**

The **tubehead** of the **panoramic unit** is **angled** so that the **x-ray beam is directed:** A. in a slightly positive vertical angulation. B in a strong positive vertical angulation. C in a slightly negative vertical angulation. D in a strong negative vertical angulation. E at zero angulation.

C. in a **slightly negative vertical angulation.**

To maintain the **same image density** when **increasing the mA**, which of the following **actions should be taken**? A. Increase kVp B. Decrease exposure time C Increase film speed D Decrease distance from source to object

B. **Decrease exposure time**

To **prevent overlapped contacts on periapical and bite-wing** images, A. position the image receptor parallel to the long axis of the tooth. B. increase vertical angulation. C. decrease vertical angulation. D. direct the x-ray beam through the interproximal contacts. E. place the image receptor to include the correct teeth on the radiograph.

D. **direct the x-ray beam** through the **interproximal contacts.**

When an **x-ray photon passes through matter**, which of the following situations is **MOST likely to occur**? A Photoelectric effect B Compton scatter C Coherent scatter D Characteristic radiation E General or Bremsstrahlung radiation F No interaction

B. **Compton scatter**

When taking a **premolar bitewing** image, which **error in the position of the PID** is seen in the photograph shown? A Greater horizontal angulation than required B Greater positive vertical angulation than required C Greater negative vertical angulation than required D The PID is correctly positioned for a premolar bitewing

C. **Greater negative vertical angulation** than required

Which factor **affects contrast**? A. Distance B kVp C. Exposure time D. mA

B. **kVp**

Which **ingredient** of the **developing solution** in the **manual processing** of x-ray **films** is **alkaline** and **aids in the softening of the emulsion?** A Potassium bromide B Potassium alum C Sodium carbonate D Sodium sulfite E Sodium thiosulfate

C. **Sodium carbonate**

Which **mandibular anatomic landmark** can be seen as a **radiolucent** area on a **mandibular premolar** periapical **(PA**) image? A Genial tubercles B Internal oblique ridge C Mental foramen D Lingual foramen E Mental ridge

C. **Mental foramen**

Which of the following **BEST describe**s the process of **heating the cathode wire** until it is **red hot and “boiling off”** of **electrons**? A Cathode ray B Beta-particles C Thermionic emission D Recoil electron E Rectification

C. **Thermionic emission**

Which of the following **BEST describes** the **purpose** of the **lead foil** contained within a **radiograph film packet**? A Shield the film from backscattered radiation B Protect the film from light C Protect the oral tissues and teeth from excess radiation D Reduce the amount of radiation received by the patient

A. **Shield the film** from **backscattered radiation**

Which of the following **concepts** are **examples of the ALARA concept**? (Select all that apply.) A Compliance with maximum permissible dose of radiation for the occupationally exposed worker B Use of evidence-based selection criteria for radiography for patient needs C Routinely scheduled radiography based on office protocol D Use of “D” speed film E Use of film holders F Shielding with lead thyroid collar and apron

A. Compliance with maximum permissible dose of radiation for the occupationally exposed worker B. Use of evidence-based selection criteria for radiography for patient needs E. Use of film holders F. Shielding with lead thyroid collar and apron

Which of the following is (are) the **maximum permissible dose (MPD)** for a dental hygienist? (Select all that apply) A. 0.5 rems a year B 5 rems a year C 50 rems a year D 50 mSv E 5 mSv

B. **5 rems a year** D. **50 mSv**

Which of the following is the **receptor that captures** **computerized images** as discrete units of information? A Sensor B Film C Pixel D Bit-depth image

A. **Sensor**

Which of the following is the **unit used to measure radiation exposure**? A Gray (Gy) B Radiation absorbed dose (rad) C Roentgen (R) Roentgen equivalent in man (rem) E Sievert (Sv)

C. **Roentgen (R)** In the newer SI system (International System of Units), there is **no unit for exposure that is equivalent to the roentgen.**

Which of the following **techniques** would be **required to correct** a **nondiagnostic bitewing** radiograph with **overlapped interproximal contacts**? A. Increasing the vertical angulation of the PID B Decreasing the vertical angulation of the PID C Changing the horizontal angulation of the PID D Increasing the kVp

C. **Changing the horizontal angulation of the PID**

Which of the following terms refers to the **majority of scatter radiation** produced in **dental imaging**? A Coherent scatter B Compton scatter C Primary scatter D Secondary scatter

B. **Compton scatter**

Which **radiolucent landmark** is visible on a **maxillary posterior periapical** image? A Genial tubercles B Mandibular foreman C Zygoma D Maxillary sinus

D **Maxillary sinus**

Which statement BEST describes a **principle of radiographic** image **magnification**? A. Greater target–receptor distance increases greater image magnification. B. Less target–receptor distance reduces image magnification. C. Greater target–receptor distance reduces image magnification. D. Target–receptor distance does not affect magnification.

C. **Greater target–receptor** _distance_ **reduces** image **magnification.**

Which statement **BEST** describes **changes to the atom** during the **ionizing process**? A. The atom gains an electron and will have a negative charge. B The atom gains an electron and will have a positive charge. C The atom loses an electron and will have a negative charge. D The atom loses an electron and will have a positive charge.

D. The **atom loses an electron** and will have a **positive charge.**

Which statement BEST describes the **kVp rule**? A. When the kVp is decreased by half, the exposure time is increased by 15. B. When the kVp is decreased by 15, the exposure time is decreased by half. C. When the kVp is doubled, the exposure time is decreased by half. D. When the kVp is increased by 15, the exposure time is decreased by half.

D. When the **kVp is increased** by **15**, the **exposure time is decreased** by **half.**

Which statement BEST describes the relationship of the image receptor and the tooth in the paralleling technique? A. The image receptor is parallel to the long axis of the tooth. B. The image receptor is slightly angled toward the long axis of the tooth. C. The central ray of the x-ray beam is directed perpendicular to the receptor and the long axis of the tooth. D. Both A and C E. Both B and C

A. The image **receptor** is **parallel to the long axis of the tooth.** and C. The **central ray of the x-ray beam** is **directed perpendicular** to the **receptor** and **the long axis of the tooth.**

You wish to **compare your patient’s current images** with images that were **taken 2 years ago.** The images from **2 years ago** have a **yellowish-brown color.** Which of the following is the **cause** of the yellow-brown **stains**? A Temperature of the water bath is colder than the developer temperature B Insufficient fixing C High developer temperature D Prolonged rinsing

B. **Insufficient fixing**

A radiograph that has **many shades of grade** is considered to have A high density. B low density. C high contrast. D low contrast.

D. **low contrast.**

All of the following are descriptions of a **ghost image on a panoramic image** EXCEPT one. Which one is the **EXCEPTION**? A. It is a similar sharpness as the original artifact. B It is a similar shape to the original artifact. C It is on the opposite side of the original artifact. D It is located higher than the original artifact. E It is larger than the original artifact.

A. It is a **similar sharpness** as the **original artifact.**

All of the following **structures could be seen** on a **maxillary molar periapical** image EXCEPT one. Which one is the **EXCEPTION**? A Coronoid process of the mandible B Mandibular condyle C Maxillary tuberosity D Hamulus E Floor of the maxillary sinus

B. **Mandibular condyle**

An **impulse is equal** to A. 1 second. B. 1⁄6 of a second. C. 1/60 of a second. D. 1/600 of a second.

C. **1/60** of a **second.**

Identify the **radiolucent area indicated** in the radiograph shown. A Abscess B Maxillary sinus C Nasal fossa D Nasal septum

B. **Maxillary sinus**

In the **formation of x-radiation**, **electrons** that strike the **nucleus** of a **tungsten atom** produce **which type of x-ray**? A Low-energy B High-energy C Both high-energy and low-energy

B. **High-energy**

Order each tissue in order of **radiosensitivity**, from **most sensitive** to **least sensitive.** Match each letter with its proper sequence number. ## Footnote 1. _____ A. Skin 2. _____ B. Oral mucosal epithelium 3. _____ C. Nervous tissue 4. _____ D. Reproductive tissue 5. _____ E. Lymphatic tissue and bone marrow 6. _____ F. Mature bone and cartilage

1. **Reproductive tissue** 2. **Lymphatic tissue and bone marrow** 3. **Oral mucosal epithelium** 4. **Skin** 5. **Mature bone and cartilage** 6. **Nervous tissue**

The **indirect theory of radiation injury** suggests that **cell damage occurs** when ionizing **radiation hits critical areas** within the cell. The **direct theory of radiation injury** suggests that **x-ray photons are absorbed** within the cell and **cause the formation** of **toxins** that in **turn damage the cell.** A. Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

B. **Both statements are false.**

The **penetrating quality** of the x-ray beam is **controlled** by the A film speed. B exposure time. C source-to-film distance. D wavelength.

D. **wavelength.**

Which of the following **describes** the **appearance** of a **carious lesion** on the **buccal or lingual surface** of a **molar** on a dental image? A Triangular, radiolucent B Triangular, radiopaque C Circular, radiolucent D Circular, radiopaque

C. **Circular,** ## Footnote **radiolucent**

Which **structure** appears as a **radiopaque line surrounding the root** of the tooth? A Trabecular bone B Cancellous bone C Lamina dura D Periodontal ligament space E Pulp

C. **Lamina dura**

Which **structure or material** will **appear the MOST radiopaque** on a dental image? A Airspace B Amalgam restoration C Periodontal ligament space D Composite restoration E Pulp

B. **Amalgam restoration**

Identify # 15