dental radiography

milliammeter (mA)

determines the number of electros available to produce x-rays

7-15mA

kilovolt peak (kVp)

force used to move electrons

60-90kVp

tube head

houses mechanical, electrical, and safety components

extension (support) arm

allows for placement of position indicating device and houses electrical cords that connect the control panel and tube head

position indicating device (PID)

aims the x-rays

round or rectangular

reduces amount of tissue exposed to x-rays

central rays (CR)

x-rays in the center of the useful beam

collimator

lead washer that restricts the size of the x-ray beam

located within the PID

density

amount of light transmitted through the film

dark films have higher density than light films

contrast

difference between shades of the radiograph

short-scale contrast

few gray shades

many black and white shades

long-scale contrast

many gray shades

many black and white shades

definition

detail

how sharp the outline of structures on a radiograph is

exposure

measurement of ionization in air produced by x-rays

absorbed dose

amount of energy deposited in any matter, living or not

dose equivalent

absorbed dose in living tissue

measured in Sv and rems

latent period

period of time before the first clinically observable symptoms occur

exposure, latent period, period of injury, recovery period

four stages of exposure

acute exposure

produces short-term effects seen within months

chronic exposure

produces long-term effects seen years after exposure

ALARA

as low as reasonably achievable

using the least amount of radiation to get appropriate diagnostic results

artifacts

blemishes or images on the radiograph that are not present in the actual object

scatter radiation

comes from the patient's head

maximum permissible dose (MPD)

maximum exposure level

50mSv per year - radiation workers

5mSv per year - pregnant workers and general public

1mSv per day

output

amount of radiation a machine produces at the end of the PID

stepwedge

tests the output of an x-ray machine

determines amounts of radiation reaching the film by measurements of film density

tests when to change solutions

lead foil attached to cardboard or tongue depressor

film speed D

Ultra-Speed

slower than F

film speed F

Kodak InSight

faster than D

requires less exposure time

lateral jaw exposure

shows either left or right half of the jaw

latent image

image made on film when expose to x-rays

must be processed to turn into a visible image

coronoid process of the mandible

bone seen on films taken in the far back of a pts mouth

radiopaque

hamular process

spike of bone seen behind the last molar

radiopaque

maxillary tuberosity

rounded portion of bone behind the last tooth

radiopaque

zygoma

portion of the cheek bone

radiopaque

sinus septum

thin bone separating the sinuses

radiopaque

floor of the sinus

lower border of the sinuses

radiopaque

nasal fossa

nasal cavity

radiolucent

median suture

"crack" between roots of maxillary central incisors

area of incomplete fusion

radiolucent

incisive foramen

hole in the bone of the maxilla and between roots of incisors

radiolucent

external oblique ridge

dense white line distal to the last molar and moving across root of molars

internal oblique ridge

located below the external oblique ridge

less dense

ridge of bone that extends across roots

mandibular canal

border on top and bottom by a white line

passageway for nerves and blood vessels

submandibular gland fossa

rounded area of bone

less dense

space for submandibular salivary gland

mental foramen

hole between roots of premolars

mental ridge

runs from the premolar region to the midline of the mandible

prominence in bone forming chin

genial tubercles

bone spikes on the inner surface of the mandible

appear as a circle in images

lingual foramen

located within genial tubercles

inferior border of the mandible

rounded edge/border of the mandible

cephalostat

standardizes and stabilizes head positioning with a cephalometric machine

films used by ortho, oral surg, and prostho

charged-coupled device (CCD)

sensor used in place of film for digital imaging

edentulous

areas of the jaw with no teeth

bent film

scratched emulsion

slanted occlusal plane

herringbone

film placed backwards (concave instead of convex)

overlapping

crowns appear to be on top of each other

cone cut

PID not centered over film

elongation

insufficient vertical angulation

teeth appear longer than actual size

foreshortening

vertical angulation too high

teeth appear shorter than actual size

fog

hazy appearance on film

many causes

black film

can be caused by overdeveloping, developer too hot, or exposure to white light after x-ray exposure

exhausted chemicals

cause film to be too light, fogged, or tinted brown

exhausted fixer pictured

developer too cool

film too light

developer too warm

film too dark

reticulation

crackled appearance

caused by extreme difference in solution temperatures

films stuck together

interproximal film

bitewing

shows crowns of both upper and lower teeth on same film

used to diagnose interproximal caries

sizes 0, 1, 2, or 3

radiolucent

portion of film that is dark due to lack of structural density

substance permits passage of x-rays with little to no resistance

radiopaque

portion of film that is light due to higher structural density

substance resists passage of radiation

secondary radiation

given off my any matter irradiated with x-rays

created when the primary beam interacts with matter and gives off energy

soft x-rays

rays of low energy and long wavelengths

have little penetrating power

removed from beam by filtration

Roentgen (R)

unit of exposure to radiation measured in air

replaced by coulombs/kg

Sievert (Sv)

measures the dose equivalent

periapical film

shows the entire tooth or teeth and surrounding tissues

PPE (personal protective equipment)

personal barriers worn to prevent contamination

gloves, mask, eyewear, and gowns

occlusal plane

plane between maxillary and mandibular teeth

forms a slight upward curve - Curve of Spee

TLD

monitoring device containing crystalline compounds that store energy when struck by x-rays

determine amount of radiation exposure

RAD

unit of absorbed dose equal to 0.01 joule/kg of tissue

approximately equal to R

replaced by Gray

Gray (Gy)

measures absorbed dose

1 Gy = 100 rad

REM

measures the dose equivalent

compares biological effects of various types of radiation

replaced by Sievert (Sv)

Iowa Department of Public Health

state radiation control agency

inspects facilities

Iowa Dental Board

ensures dental assistants meet minimum training standards

issues qualification in dental radiography

conditions for an assistant to take radiographs

assistant is qualified in dental radiography or is on trainee status

dentist orders films

dentist provides supervision

conditions for trainee to take radiographs

dentist orders films

dentist provides personal supervision

requirements to obtain radiography qualification

course of study with clinical training

examination

application with fee

radiography qualification renewal

renewed with registration by August 31 of odd-numbered years

renewal requirements

proof of 2 hours of con ed in dental radiography and renewal fee

penalties for violating requirements

disciplinary action by the dental board

criminal charges or civil action

false

a dentist should always prescribe radiographs every six months to review a patients dental condition

false

certified dental assistant does not need to obtain a separate radiography qualification from the Board to take x-rays

true

dental assistant trainees can train in dental radiography during trainee period

false

Iowa Dental Board inspects dental radiography machines

control panel

timer

mA setting

kVp setting

detail/definition

if a pt is moving, what film quality is affected

decrease mA or decrease time

how to lighten a film's density

increase kVp

how to increase the number of shades

proper density

contrast

detail

shows entire area and surrounding structures

four factors of a diagnostically acceptable radiograph

movement of pt, film, or tube head during exposure

length of PID

causes of poor detail

filters

absorbing material that remove some radiation

usually aluminum

placed in path of beam

muscle

nerve and brain

bone

connective

skin

immature reproductive cells

blood cells

tissue sensitivity from most to least resistant

effects of chronic exposure

shortened life span

cataract formation

embryologic defects

genetic mutations

cancer