dental terms + radiography review

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periapical radiographs

identifies abscess, cysts, and granuloma’s that occur at the apex of a tooth's root, appears radiolucent (dark) , indicates bone loss and decay

bitewing radiographs

used to detect cavities, interproximal caries, and monitor overall dental health. can also capture both upper and lower teeth in one image.

occlusal radiographs

taken by placing film against biting surface of teeth to visualize larger areas of maxilla and mandible and detect abnormalities.

adult film size = #4 ; child film size = #2 ; small pediatric = #0

cephalometric radiographs

side profile radiograph containing skull, teeth, and neck. used primarily by orthodontists to assess bone growth and development.

panoramic

wide view x-ray of the teeth, jaws, and surrounding structures, allowing for the assessment of dental abnormalities, wisdom teeth positioning, and jaw-joint issues.

Cone Beam Computed Tomography (CBCT)

3D imaging technique used to provide detailed views of dental structures, soft tissue, nerves, and bones. used for root canals, implant planning, viewing jaw structure, and assessment of bone growth

density

overall darkness of an image

bite-wing block

device used to hold digital sensors in place during radiograph

bite-wing tab

small adhesive tab used to hold digital sensors against the teeth

contrast

controls light and dark shades of an image

position indicating device (PID)

aiming device used to direct the x-ray beam accurately towards the image receptor (after use, it’s disinfected)

paralleling technique

technique that uses an image receptor placed parallel to the long axis of the long axis of the tooth with an x-ray beam directed perpendicular (⊥) to both the film and the tooth

bisecting technique

a technique where the image receptor is aligned against the angle between the tooth and the film, directing the x-ray beam perpendicularly to the bisecting line

pros: useful against shallow palates

tori

bony growths in oral cavity (maxillary/mandibular), may obstruct receptor placement

PID / Central Ray placement errors

incorrect positioning may lead to image distortion

tubehead placement

horizontal error = overlapping contacts
vertical error = image elongation / foreshortening

photostimuable phosphor (PSP)

an image storing system which captures and stores X-ray images for later processing (can be scratched, MUST be deleted after use or else double images)

complementary metal-oxide semiconductor (CMOS)

converts X-rays into digital signals for immediate display and analysis (fast&accurate) CCD (Charged-Couple Device) and CMOS are same thing

legal requirements

HIPAA - image privacy, confidential records should not be discussed (patient name must not be disclosed)
Retention - must keep images for 7+ years (pediatric dentists must keep until 18+)
Transfer - must comply with patient consent and new dental provider must request images (only by copy, not OG images)
Ownership - legally the dental office owns images, but patient has rights to them
Charting - document date (listed first), type of radiograph, reason for image

anatomy of skull

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cathode (-)

negatively charged electrode in an X-ray tube that emits electrons when heated

anode (+)

positive electrode, purpose is to convert electrons into x-ray photons

x-ray tube

the heart of the x-ray generating system

metal housing of tubehead

protects and encloses the x-ray tube, preventing radiation leakage and ensuring safety during imaging procedures

insulating oil

prevents overheating by absorbing the heat created by the production of x-rays

tungsten filament

coiled wire made of tungsten (metal) which produces electrons when heated

⠀tube head seal

allows the exit of xrays from the tube head. seals the oil inside tube head and acts as a filter to X-ray beam

aluminum disks

added filtration. filters out low energy, long wavelength x-rays

collimator

restricts the size and shape of the x-ray beam

unleaded glass window of tube head

allows x-rays to exit the tube while preventing leakage of radiation, directs beam right toward the aluminum disks, lead collimator, and PID

primary radiation

xrays emitted directly from the x-ray tube that have not been altered or scattered

secondary radiation

x-radiation (high energy radiation) created when primary radiation interacts with matter (patient, equipment, or wall)

scatter radiation

a form of secondary radiation that occurs when deflected (direction changes after an interaction) from its original path after interacting with matter

leakage radiation

x-rays that escape from the tube-head’s (checked for annually)

3 consistent parts of x-ray unit

control panel, extension arm, tube head

The two types of filtration

inherent and added filtration

Inherent filtration

takes place when the primary beam passes through the glass window of the xray tube, the insulating oil, and tubehead seal
- Approx. 0.5-1.0 mm

acute exposure

large dose in a short period of time

chronic exposure

small doses over a long period of time

latent exposure

time between exposure to ionizing radiation (powerful energy which creates charged particles called ions) and appearance of symptoms

kVp (kilovoltage peak)

affects the penetration and quality of the x-rays produced (controls density) , recommended amount is 60-70 kV

mA (milliamperage)

quantity (amount) of the X-ray beam, 1/1000 of an ampere, ranges from 7 to 15 mA (must not exceed or else overheating)

Aluminum filtration of a x-ray machines operating at or below 70kVp

1.5 mm aluminum

Aluminum filtration of a x-ray machines operating at or above 70kVp

2.5 mm aluminum

results from increasing exposure time

darker image (too dark = overexposure)

results from decreasing exposure time

lighter image (too light = underexposure)

ALARA means ?

As Low As Reasonably Achievable

somatic effects

only affects the individual exposed to radiation

genetic effects

passed down to offspring (through reproductive cells)

most to least sensitive to radiation (in order)

reproductive cells (sperm/eggs), bone marrow, thyroid, lungs, skin, the eye, muscle, nerves

The maximum permissible dose (mpd) per year for radiation workers is ___ rems/millisieverts a year?

0.5 rems, or 50mSv a year

Meaning of EPA

Environmental Protection Agency

units of radiation measurements & conversion

roengten equivalent man - rem

roengten - R

Sievert - Sv

gray - Gy

Coulombs per kg - C/kg

Gy to Rad: 1 Gy = 100 rad

Sv to Rem: 1 Sv = 100 rem

Rad to Gy: 1 rad = 0.01 Gy

Rem to Sv: 1 rem = 0.01 Sv

cumulative mpd per year

10 mSv/year times age in years

sterilization

to make free from bacteria and other microorganisms, often through heat or chemicals (such as forceps, scalers, beam alignment device, sensor positioning device)

disinfection

the process of reducing harmful microorganisms from objects and surfaces, typically through the use of wipes/sprays ((PID, extension arms, tube head, lead apron (after each use), PSP (must erase))

barriers

prevents radiation exposure and minimizes cross-contamination, includes physical barriers such as walls, lead aprons, and plastic covers. (including but not limited to the dental chair, control panel, tubehead, digital sensor, countertops, computer keyboard, headrest of chair)

Before x-ray exposure:

• adjust chair

• adjust headrest

• place lead apron

• place barriers

After x-ray exposure:

• dispose of contaminated items

• take reusable equipment to sterilization

• remove lead apron

Asepsis

the state of being free from disease-causing contaminants, ensuring a sterile environment

Antiseptic

a substance that prevents infection by killing or inhibiting the growth of pathogens