The measurement of the number of electrons moving through a conductor. Measured in amperes (A) or milliamperes (mA)
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)
Can increase or decrease the number of electrons passing through the cathode filament
Used to decrease voltage from the incoming 110- or 220-line voltage to the 3 to 5 volts used by the filament circuit.
Used to increase incoming voltage to 65,000 to 100,000 volts used by the high-voltage circuit.
Produced when an electron hits the nucleus of a tungsten atom or passes very close to the nucleus of a tungsten atom.
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.
A form of secondary radiation, the result of x-rays that has been deflected from its path by an interaction with matter.
Darkness or blackness on film. If kVp is increased film will be darker. If decreased, film will be lighter
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.
Nonthreshold dose-response curve
Suggest that no matter how small the amount of radiation received, some biologic damage occurs.
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)
Time between exposure to ionizing radiation and the appearance of observable clinical signs.
Quantity of radiation received or total amount absorbed (more damage with tissue absorbing large quantities of radiation)
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)
Reproductive (ova, sperm). Effects are passed on to generations. Genetic damage cannot be repaired
Primary beam passes through glass window, insulating oil, tubehead seal. 0.5 to 1.0 mm of aluminum
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.
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
Rectangular and round PID
8 inch and 16 inch; longer are preferred due to less divergence of beam, open ended and lead lined.
"Arranged like a lattice"->soft, spongy bone located between 2 layers of cortical bone; spaces are trabeculae that are filled with bone marrow.
Opening/hole in bone that allows the passage of blood vessels/nerves and appears radiolucent
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
Pear shaped compartment, appears above maxillary incisors. Appears as a large radiolucent area above the maxilla.
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
Tubes within maxillary sinus that carry nerves, blood supply, radiolucent band with boundary of two radiopaque cortical bony lines
Intersection of maxillary sinus and nasal cavity, radiopaque, cortical bone; above maxillary canine.
"hooklike", posterior to maxillary tuberosity; extension of medial pterygoid plate of sphenoid bone; radiopaque
Bump of bone, muscle attachment; lingual aspect of mandible, "ring shaped" radiopacitiy below mandibular incisors.
Hole in bone below mandibular premolars, blood supply to lower lip exits here; radiolucent; often misdiagnosed for periapical pathology
Internal ridge of mandible muscle attachment, continuous with internal oblique ridge; radiopaque line
tube that travels length of mandible, radiolucent; has cortical walls, houses inferior alveolar nerve
External Oblique Ridge
superior to internal oblique ridge; anterior border of ramus ends in external oblique ridge; radiopaque band
depression of bone; submandibular salivary gland found here; radiolucent; below mylohyoid ridge
anterior ramus of mandible; attachment for muscle of mastication; superimposed around maxillary tuberosity.
Periodontal Ligament Space
Space between root and the lamina dura, thin, radiolucent line, healthy PDL is uniform thickness
Reduces exposed silver halide crystals into black metallic silver a makes dark/black areas on film; unexposed silver halide crystals are unaffected by developer
Removes unexposed silver halide crystals and creates white/clear areas on film; black metallic silver remains on film.