Modern Dental Assisting chapter 38

What does dental imaging do?

Enables the dentist to see conditions that are not visible in the oral cavity

What's important to know about radiation exposure?

Any exposure, no matter how small, has the potential to cause biologic changes to operator and patient

What are all the uses of dental images?

Detect dental caries and bone loss in early stages, locate abnormalities in surrounding hard and soft tissues, evaluate growth and development, provide information during dental procedures, document patients condition at specific time

Who discovered radiation?

Wilhelm Conrad Roentgen

What are all things in the world composed of?

Energy and matter

Atoms

Basic form of matter, contain energy

Energy

Capacity to do work

Matter

Anything that occupies space and has form or shape, made of molecules

What are the two parts to an atom

Central nucleus and orbiting electrons

How are atoms identified?

Composistion of nucleus and arrangement of orbiting electrons

What disrupts electron orbit?

X-rays

What is the nucleus composed of?

Protons and neutrons

Protons

Carry positive electric charge, subatomic particle

Neutrons

Carry no change, subatomic particle

Do dental x-rays affect the nucleus

No, only the orbiting electrons

Can dental x-rays make atoms radioactive

No, therefore patients can never ‘give off’ radiation

Electrons

Tiny, negatively charged particles with very little mass. Orbit the nucleus

What is the orbit path of an electron called?

Electron shell, only has a specific number of electrons. They’re also maintained in orbit

Ionization

The process where an atom gains or loses an electron and becomes electrically unbalanced (ion is produced as well)

Photon

A minute bundle of energy that has no weight or mass, is the one that hits the atom

What can X-rays penetrate

Everything besides metal

What is electromagnetic radiation made up of

Photons that travel through space at the speed of light in a straight line with a wavelike motion

What determines the energy of the wavelength?

The size. The shorter the wavelength the more energy it has

What are the three main components of the dental x-ray machine?

Tube head, extension arm, control panel

What is ‘braking’ or bremsstrahlung radiation?

electromagnetic radiatio produced when a charged particle(electron) suddenly slows down or changes direction

What are 4 characteristics of X-rays

No charge, travel at the speed of light, can cause changes in living cells, invisible or undetected by the senses

What is the X-ray tubehead?

A tightly sealed, heavy metal housing that contains X-ray tube and produces dental x-rays

How thick is an alluminium sheet?

0.5 mm thick

What is the extension arm?

Positions the tubehead, folds up and can swivel side to side. Never should be help during exposure

X-ray tube?

Where x-rays are produced, electrons can flow with minimal resistance

Step up transformer?

Increases electrical voltage from the input side tot he output side while decreasing the current

Step down transformer?

Reduced the high voltage from an electrical power source down to a lower, safer voltage level

Anode(+)

Acts as the target for electrons

Cathode(-)

Supply electrons necessary to generate x-rays

Tungsten filament

Acts as the source of electrons

Tubehead seal?

Keeps oil in tubehead and acts as a filter for the x-ray beam

Aluminium filter

Filters out the nonpenetrating, longer wavelength radiographs

Lead collimator?

Limits the size of x-ray beam

PID (processor indicator device)

Aims the x-ray beam at the sensor in the patients mouth

Unleaded glass window?

Where the x-ray passes through

Insulating oil

Prevents overheating

Metal housing

Contains the x-ray tube so no radiation escapes

What are the main reasons epopek don’t want x-rays?

They think their dangerous, financial/comfort concerns

When are full mouth series taken?

Every 5-7 years

What is a pano(ramie) x-ray?

A type of x-ray where it captures your entire mouth, upper and lower jaw, teeth, sinuses, and jaw joints in a single img (less detail!)

What is a full mouth series (FMX) x-ray?

a complete set of 18 to 20 individual dental X-rays that show every tooth, root, and the surrounding jawbone (more detail!)

What is the acronym for radiation concerns?

ALARA (as low as reasonably achievable)

What is the purpose of x-rays?

To show things that aren’t clinical

How much radiation do you get from a single dental x-ray?

0.0002

What does the lead apron do?

Protect body systems sensitive to radiation

radiolucent

Areas where X-rays pass straight through the body, areas where its thin, aka black areas

radiopaque

Areas where X-rays are blocked or absorbed by dense materials, high-density structures like bone, white areas

What type of filling is this?

Amalgam

Periapicals (PA)

Shows the crown to the apex (root) aka the entire structure of the tooth

What side are anterior teeth when x-rays are taken?

Vertical

What side are posterior teeth when x-rays are taken?

Sideways

What things are radiopaque?

Amalgam fillings, metal crowns, braces, dense bone, implants, enamel

What does the control panel of an x-ray contain?

Master switch (orange=on), indicator light (x-ray taken=red), selector buttons (settings), exposure button (Shoots out radiation)

What does the selector button control?

Time, milliamperage (mA selector, kilovoltage (kVp) selector

What does red mean on the control panel?

Don’t come in, radiation is happening

What does the exposure button do the lights and cathode

Makes cathode heat up and turns on indicator light

what is the master switch used for?

Turn the machine on and off

What does the different indicator light colors do?

Orange shows when master switch is on. Red comes on when exposure button is being pushed and x-rays are being emitted

What does the exposure button do specifically?

Controls the flow of electricity to generate the x-rays, it’s measured in fractions of a second, called impulses. (60 impulse=1 sec)

(mA) is what?

A setting where the amount of electrons is produced. Controls exposure. 7-15 range. Milliamperage

(kVp) is what?

A setting that gives the x-ray beams power, 60-90 range, Kilovoltage peak

What’s the difference between KVP and mA

KVP(owner) Ma(mount)

What does the heating of filament lead to?

Thermionic (temp/to heat) send. Sends electrons, essentially

What is the written script sequence?

Idk

What does the molybdenum cup do?

It’s in the cathode, it directs electrons to the tungsten target. When it strikes, their energy of motion (KE) is converted to x-ray energy and heat

How much of the energy is converted to x-rays?

Less than 1%, 99% is lost as heat, which explains the oil in the machine

What removes the longer-wave length rays?

The aluminum filter

What is thermionic emission?

When the tungsten filament heats up and sends out heat

What is primary radiation?

made up of x-rays that come from target of x-ray tube (useful/primary beam)

What is secondary radiation

x-radiation that is created when the primary beam interacts with matter (absorbed)

What is scatter radiation?

A form of secondary radiation: occurs when x-ray beam is deflected from its path by interaction with matter