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Amperage

The measurement of the number of electrons moving through a conductor. Measured in amperes (A) or milliamperes (mA)

Voltage

The measurement of electrical force that causes electrons to move from a negative pole to a positive one. Measured in volts (V) or kilovolts (kV)

Milliamperage adjustment

Can increase or decrease the number of electrons passing through the cathode filament

Kilovoltage peak adjustment

Can control the current passing from the cathode to the anode.

Step-Down Transformer

Used to decrease voltage from the incoming 110- or 220-line voltage to the 3 to 5 volts used by the filament circuit.

Step-Up Transformer

Used to increase incoming voltage to 65,000 to 100,000 volts used by the high-voltage circuit.

General Radiation

Produced when an electron hits the nucleus of a tungsten atom or passes very close to the nucleus of a tungsten atom.

Characteristic Radiation

Produced when a high-speed electron dislodges an inner-shell electron from a tungsten atom and causes ionization of that atom. Occurs only at 70 kVp and above.

Primary Radiation

The penetrating x-ray beam that is produced at the target of the anode

Secondary Radiation

X-radiation created when the primary beam interacts with a matter

Scatter Radiation

A form of secondary radiation, the result of x-rays that has been deflected from its path by an interaction with matter.

Compton Scatter

The x-ray photon is deflected from its path during its passage through matter

Coherent Scatter

An x-ray photon that has its path altered by matter.

Density

Darkness or blackness on film. If kVp is increased film will be darker. If decreased, film will be lighter

Contrast

Sharper of dark and light areas and how they are separated on film. Low kVp results in high contrast (many white and black areas, very little gray). Useful when diagnosing decay. High kVp results in low contrast (many shades of grade) Useful for periodontal disease screening/periapical disease

Free Radical Formation

Cell damage occurs through formation of "free radicals". Free radicals are formed when an x-ray photon ionizes water.

Direct Injury

Occurs very little; most photons pass through cell with little or no damage

Indirect injury

Occurs frequently due to the high concentration of water in cells.

Nonthreshold dose-response curve

Suggest that no matter how small the amount of radiation received, some biologic damage occurs.

Stochastic effects

A direct function of the dose. No dose threshold; effects do not depend on the magnitude of the absorbed dose (Examples: cancer and genetic mutations)

Nonstochastic (deterministic) effects

Somatic effects that have a threshold; effects increase in severity with increasing absorbed dose. (Examples: Erythema, loss of hair, cataracts, and decreased fertility)

Latent Period

Time between exposure to ionizing radiation and the appearance of observable clinical signs.

Total dose

Quantity of radiation received or total amount absorbed (more damage with tissue absorbing large quantities of radiation)

Dose Rate

Rate which exposure to radiation occurs and absorption occurs (more damage occurs with high dose due to rapid delivery and does not allow for repair)

Amount of tissue irradiated

Area of body exposed total body produced more adverse effects

Cell sensitivity

More damage can occur in younger or rapidly dividing cells

Short-term effects

Do not occur in dentistry

Long-term effects

Effects seen years, decades, or generations later

Somatic cells

All cells except reproductive; effects are seen in person irradiated

Genetic cells

Reproductive (ova, sperm). Effects are passed on to generations. Genetic damage cannot be repaired

Radiosensitive cells

Small lymphocyte, bone marrow, reproductive cells, immature bone

Radioresistant cells

Mature bone, muscle, nerve

Roentgen

Coulombs per kilogram

Rad (Radiation absorbed dose)

Gray

Rem (Roentgen equivalent (in) man)

Sievart

Inherent filtration

Primary beam passes through glass window, insulating oil, tubehead seal. 0.5 to 1.0 mm of aluminum

Added filtration

Aluminum disks between collimator and tubehead seal. Aluminum disks filter long wavelength, low energy x-rays from x-ray beam. 0.5 mm increments

Total (inherent + added) filtration

Dental x-ray machines operating 70 kVp or below: minimum 1.5 mm aluminum filtration
Dental x-ray machines operating above 70 kVp: minimum of 2.5 mm. of aluminum filtration.

Collimation

Restricts size and shape of beam to lower patient exposure
Round: cone shaped beam-2.75 inches in diameter
Rectangular: Rectangular beam slightly larger than size 2 film- lowers patient exposure

Conical PID

Closed, pointed cone-high production of scatter, not used any longer.

Rectangular and round PID

8 inch and 16 inch; longer are preferred due to less divergence of beam, open ended and lead lined.

Cortical Bone

"Cortex"-> dense, outer layer; also called compact bone-appears radiopaque on film

Cancellous

"Arranged like a lattice"->soft, spongy bone located between 2 layers of cortical bone; spaces are trabeculae that are filled with bone marrow.

Process

Marked prominence that appears radiopaque.

Ridge

Linear prominence that appears radiopaque.

Spine

Sharp, thornlike projection that appears radiopaque.

Tubercle

Bump or nodule that appears radiopaque

Tuberosity

Rounded prominence that appears radiopaque

Canal

Tube that passes through bone, contains nerve canals/blood vessels/and appears radiolucent

Foramen

Opening/hole in bone that allows the passage of blood vessels/nerves and appears radiolucent

Fossa

Scooped out of depressed area of bone that appears radiolucent

Sinus

Hollow space, cavity that appears radiolucent

Septum

Bony wall that divides 2 spaces, radiopaque

Suture

A line of union between adjoining bones, found only in skull; appears as radiolucent line

Incisive (Nasopalatine) Foramen

Located at the midline of anterior portion of hard palate behind maxillary central incisors; round radiolucency between roots of centrals

Superior Foramina of incisive canal

Two small openings (radiolucent) found on floor of nasal cavity->common exit is incisive foramen

Median palatine suture

Extends from alveolar bone between maxillary centrals to posterior hard palate; seen as a radiolucent line

Lateral Fossa

Between canine and lateral incisor, depression is not always visible, radiolucent

Nasal Cavity/Fossa

Pear shaped compartment, appears above maxillary incisors. Appears as a large radiolucent area above the maxilla.

Floor of Nasal Cavity

Cortical bone, radiopaque band above maxillary incisors

Anterior Nasal Spine

V-shaped radiopacity at intersection of floor of nasal cavity and septum

Inferior Nasal Conchae

Thin, curved areas of bone, radiopacities within nasal cavity and septum

Maxillary sinus

Located above maxillary premolar/molar teeth, border is made up of cortical bone; sinus cavity is radiolucent compartment

Septa within maxillary sinus

Within maxillary sinus; acts as a division, radiopaque lines sometimes not visible

Nutrient Canals

Tubes within maxillary sinus that carry nerves, blood supply, radiolucent band with boundary of two radiopaque cortical bony lines

Inverted Y

Intersection of maxillary sinus and nasal cavity, radiopaque, cortical bone; above maxillary canine.

Maxillary Tuberosity

bony prominence posterior to maxillary third molar; radiopaque

Hamulus

"hooklike", posterior to maxillary tuberosity; extension of medial pterygoid plate of sphenoid bone; radiopaque

Zygomatic process of maxilla

cortical bone; J or U shaped radiopacity

Zygoma

"Cheekbone"; cortical bone; radiopaque band extending from zygomatic process.

Ramus

Posterior to mandibular third molar

Body of Mandible

U-shaped portion extending from ramus to ramus

Alveolar Process

encases/supports teeth

Genial Tubercles

Bump of bone, muscle attachment; lingual aspect of mandible, "ring shaped" radiopacitiy below mandibular incisors.

Lingual Foramen

Surrounded by genial tubercle, hole in bone near mandibular midline, radiolucent

Nutrient Canals

Mostly seen in mandibular nerve/blood supply vertical radiolucent lines

Mental Foramen

Hole in bone below mandibular premolars, blood supply to lower lip exits here; radiolucent; often misdiagnosed for periapical pathology

Mylohyoid Ridge

Internal ridge of mandible muscle attachment, continuous with internal oblique ridge; radiopaque line

Mandibular Canal

tube that travels length of mandible, radiolucent; has cortical walls, houses inferior alveolar nerve

Internal Oblique Ridge

Continues from ramus; radiopaque band

External Oblique Ridge

superior to internal oblique ridge; anterior border of ramus ends in external oblique ridge; radiopaque band

Submandibular Fossa

depression of bone; submandibular salivary gland found here; radiolucent; below mylohyoid ridge

Coronoid Process

anterior ramus of mandible; attachment for muscle of mastication; superimposed around maxillary tuberosity.

Lamina Dura

Surrounds root, cortical bone, radiopaque

Alveolar Crest

coronal part of alveolar bone, between teeth, cortical bone, radiopaque

Periodontal Ligament Space

Space between root and the lamina dura, thin, radiolucent line, healthy PDL is uniform thickness

Developer Solution

Reduces exposed silver halide crystals into black metallic silver a makes dark/black areas on film; unexposed silver halide crystals are unaffected by developer

Fixer Solution

Removes unexposed silver halide crystals and creates white/clear areas on film; black metallic silver remains on film.

What is the optimum temperature for manual processing?

68 Degrees F

What are the conditions required for the darkroom

16-20 square feet (at least 4x4)
Light tight
Safelight must be at least 4 feet from the working area

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