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155 Cards in this Set

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How many PA's and BW's are there in an FMX?
16 PA's 4 BW's
What is recorded in a PA?
The outline, position, mesiodistal extent, and surrounding structures are recorded. Along with the full length of the tooth and 2-4mm of surrounding NORMAL bone (more if there is a pathology), interproximal contacts should be open.
What is recorded in a BW?
Outline, position, mesiodistal extent, and the coronal part of tooth and bone of both arches. Indicated for evaluation of interproximal tooth surfaces and interproximal bone level.
What is vertical angulation and why is it important?
The up and down motion of the X-ray tube in relation to the occlusal plane. Important to capture the entire length of the tooth.
What is horizontal angulation and why is it important?
motion of the tube around the pt's head in relation to the midsagittal plane. Important to be able to open the contacts.
What does an XCP consist of, and what is an XCP used for?
Anterior and posterior bite blocks, indicator rod, and an aiming ring. Used for an external guide to position the x-ray beam vertically and horizontally to the film. The xcp also establishes a point of entry for the beam.
What is used instead of an xcp when space is limited or mand tori are present?
Disposable bite blocks/stabes, BW loops and adhesive tabs. Snap-a-ray film holder is used for endo cases.
What is the significance of the "dot" and how should it be positioned?
The dot should always be toward the area of interest and the x-ray beam. It should be placed in "the slot." For a PA it should be on the incisal or occlusal side of the film, for BW should be placed toward the lower edge (or periapical).
What are the advantages of film holders?
Facilitates retention and film placement, relates the film to the BID, may collimate the beat, reduced dose to pt.
What are the BID types?
Long round open, long rectangular open, and short round open.
What re the advantages of the XCP?
Prevents BID/cone cuts, aiming ring is compatible with rectangular and round BID, indicator arm guides BID for proper alignment reduced distortion, and steam autoclavable.
What are the 4 basic principles of intraoral radiography?
Pt head position, location of the long axes of the tooth, x-ray beam angulations, and point of entry of the x-ray beam.
What is the significance of pt. head position?
It should be:
-upright pt. position
-midsagittal plane perpendicular to floor
-occlusal place (ala-tragus line) II to floor

(Ala-tragus=parallel tips of maxillary teeth from canine to 3rd molar)
What is the significance of the long axes of the teeth?
In the Maxilla: they are all tilted facially
In the Mandible:
-Anterior teeth tilted facially
-Premolars are basically vertical
-Molars have a lingual inclination
What happens if you underangulate?
elongation of structures, the BID is too low!
How many PA's and BW's are there in an FMX?
16 PA's 4 BW's
What is recorded in a PA?
The outline, position, mesiodistal extent, and surrounding structures are recorded. Along with the full length of the tooth and 2-4mm of surrounding NORMAL bone (more if there is a pathology), interproximal contacts should be open.
What is recorded in a BW?
Outline, position, mesiodistal extent, and the coronal part of tooth and bone of both arches. Indicated for evaluation of interproximal tooth surfaces and interproximal bone level.
What is vertical angulation and why is it important?
The up and down motion of the X-ray tube in relation to the occlusal plane. Important to capture the entire length of the tooth.
What is horizontal angulation and why is it important?
motion of the tube around the pt's head in relation to the midsagittal plane. Important to be able to open the contacts.
What does an XCP consist of, and what is an XCP used for?
Anterior and posterior bite blocks, indicator rod, and an aiming ring. Used for an external guide to position the x-ray beam vertically and horizontally to the film. The xcp also establishes a point of entry for the beam.
What is used instead of an xcp when space is limited or mand tori are present?
Disposable bite blocks/stabes, BW loops and adhesive tabs. Snap-a-ray film holder is used for endo cases.
What is the significance of the "dot" and how should it be positioned?
The dot should always be toward the area of interest and the x-ray beam. It should be placed in "the slot." For a PA it should be on the incisal or occlusal side of the film, for BW should be placed toward the lower edge (or periapical).
What are the advantages of film holders?
Facilitates retention and film placement, relates the film to the BID, may collimate the beat, reduced dose to pt.
What are the BID types?
Long round open, long rectangular open, and short round open.
What re the advantages of the XCP?
Prevents BID/cone cuts, aiming ring is compatible with rectangular and round BID, indicator arm guides BID for proper alignment reduced distortion, and steam autoclavable.
What are the 4 basic principles of intraoral radiography?
Pt head position, location of the long axes of the tooth, x-ray beam angulations, and point of entry of the x-ray beam.
What is the significance of pt. head position?
It should be:
-upright pt. position
-midsagittal plane perpendicular to floor
-occlusal place (ala-tragus line) II to floor

(Ala-tragus=parallel tips of maxillary teeth from canine to 3rd molar)
What is the significance of the long axes of the teeth?
In the Maxilla: they are all tilted facially
In the Mandible:
-Anterior teeth tilted facially
-Premolars are basically vertical
-Molars have a lingual inclination
What happens if you underangulate?
elongation of structures, the BID is too low! The apices are cut off, and basically no PA is seen
What happens if you overangulate?
Foreshortening of structures, BID too high, coronal aspects cut off, and too much periapical bone is seen.
Where should the point of entry of the x-ray beam be?
this should be directed to the center of the region of interest. This ensures that the object is completely covered.
What happens if there is an error in the point of entry of the x-ray beam?
Cone cut/Bid cut (partial image)
What are the two PA radiographic techniques?
1. Paralleling
2. Bisecting the angle
What are the specifics of the paralleling technique?
Preferred technique:
-better anatomical detail
-minimizes the undesirable unsharpness, magnification and shape distortion
What are the rules of the paralleling technique?
1. Film should be II to long axes of teeth
2. Central Ray (CR) is perpendicular to the long axes of the teeth and film plane
What is the procedure sequence of the paralleling technique?
1. Place fim in holder
2. Position film to cover area of interest in the mouth
3. Position film plane II to teeth\
4. Horizontal angulation: BID horizontally II to indicator rod
5. Verical angulation: BID is vertically II to indicator rod.
6.Center the X-ray beam on the center of the film packet
What is the bisecting the angle technique?
angle formed by the plane of the tooth and the plane of the film is bisected and the central ray is directed through the apex of the tooth perpendiculat to the bisecting line.
What are the procedures of the bisecting the angle technique?
1. Head position: Occlusal plane II to floor and midsagittal plane perpendicular.
2. Film: placement and retention: center film behind region with bite block
3. Vertical angulation: CR through the center of the field and perpendicular to the bisected angle.
4. Horizontal angulation: CR perpendicular to the facial surface of the teeth in the region
5. Central Ray: centered on film; long cone recommended.
What are the shortcomings of the bisect the angle tech.?
-More difficult
-Can't see the long axes of the tooth: so much estimate
-Have to image the bisected angle
-the film placement is not completely visualized.
-errors like film bending and improper placement if not done correctly
When is a vertical BW indicated?
To visualize severe alveolar bone loss...this is the best way to view alveolar bone loss!
Who developed the BW radiograph?
Howard Raper; Indiana University
Where should the head be positioned when taking a BW?
Sagittal plane perpendicular to the floor; occlusal plane II to the floor.
Where should the BID be positioned in BW radiography for Horizontal and Vertical angulation to be correct?
Horizontal angulation: CR through the embrasures/contacts
Vertical angulation:
-Premolar: +10 degrees
-Molar: +20 degrees
What size film should be used in an FMX of an adult dentulous pt?
Size 1 for anterior PA's
Size 2 for posterior PA's and BW's
How should the Maxillary central-lateral incisor PA be placed in the mouth?
vertically, centered on the central and lateral, CR directed through the Central-lateral contact. To be ideal, the contact between the C/L should be open, the incisal edges should be just above the lower border of the film, the midline should be visible, and 2-4mm of PA bone present.
How should the maxillary canine PA be placed in the mouth, and what are the ideal features?
Midline of canine centered on film, CR through the mesial contact (only this contact will be open), 2-4mm of PA bone, incisal edges just above the lower border of the film.
How should the maxillary premolar PA be placed in the mouth, and what are the ideal features?
Size 2 horizontally, should cover the PM's and the distal contact of the canine, CR through the contact b/w the 1 and 2nd PM or 2nd PM and 1st M; 2nd PM should be centered on the film, contact between the PM's and the distal contact of canine should be open, 2-4mm PA bone, occlusal plane slightly above the lower border of the film, and the buccal and lingual cusps superimposed.
How should the maxillary molar PA be placed in the mouth, and what are the ideal features?
2nd M is centered, posterior border of the film should cover the maxillary tuberosity and distal of last molar, CR is directed to pass through the contact b/w the 1st and 2nd molar; contacts b/w the molars should be open, tuberosity visible, 2-4mm PA bone, occlusal plane just above lower border, and B&L cusps superimposed
How should the mandibular central/lateral incisor PA be placed in the mouth, and what are the ideal features?
C/L are centered, CR through the contact b/w the C/L and it should be open; 2-4mm PA bone, midline visible.
How should the mandibular canine PA be placed in the mouth, and what are the ideal features?
Midline of canine centered on the bite block, CR through the mesial contact, and it should be open, 2-4mm PA bone visible.
How should the mandibular premolar PA be placed in the mouth, and what are the ideal features of this radiograph?
Size 2 horizontally, II to the long axes of teeth, PM and distal contact of canine; CR b/w the PM's or the 2nd PM and 1st M; 2nd PM should be centered, contact b/w the PM's and the distal contact of canine should be open, B&L cusps superimposed.
How should the mandibular molar PA be placed in the mouth, and what are the ideal features of this radiograph?
Posterior border of film should cover the 3rd molar area and distal of last molar, CR throught the contact b/w the 1st and 2nd M; 2nd molar should be centered, contacts b/w molars should be open, mandibular ascending ramus should be visible, 2-4mm PA bone, B&L cusps superimposed, occlusal plane just below the superior border of the film
What are some of the basic principles of intraoral radiography?
Film is placed II to long axes of teeth, CR is directed perpendicular to axes, film holder is used to keep film II to axes, object-film distance must be increased to keep film II (magnification and distortion if not), source-film distance should be increased to avoid magnification (longer BID is used)
What does the occlusal radiograph record, and what are its uses?
Records the cross section of the arches, incisal and occlusal surfaces of teeth; used for detection of impacted teeth, fractures, foreign bodies, jaw lesions, and salivary stones.
Where is the CR direced in an occlusal radiograph? What is the Angulation?
CR is directed through the bridge of the nose to the film (maxillary) and through the midline of the floor of the mouth (mandibular); 60-65 vertical angulation maxillary; -90 vertical angulation mandibular.
What are some anatomic variations that affect intraoral radiography?
Tori, edentulous ridges, apprehensive pt?, tongue size, depth of palate, high muscle attachments
What is the significance of edentulous ridges?
less exposure time (25% less), 14 film FMX with size 2 using stabes (1 midline, 2 lateral/canine, 2 PM, and 2 molar projections), pano is the quickest and least uncomfortable.
What are some ways to manage an apprehensive pt?
These pt's are hypersensitive, can use: tissue protectors, topical anesthetics (chloroseptic spray), film bending, tranquilizers
What are some ways to manage the gagging pt?
Reduce psychic stimuli: pleasant first contact and discussion with pt in a kindly manner, anteriors taken first (posterior lower PA's are hardest), divert pt. attention, premed
What are some other ways to manage the gagging pt.
reduce tactile stimuli, minimal film motion in mouth, minimal contact with mucosa, use film holders & edge cushions, use desenstizers, be quick, have help, combine intra and extraoral films if necessary.
What is a good radiograph?
Has proper visual characteristics and minimal projection geometry
What does the diagnosic quality of a radiograph depend on?
Proper visual charactaristics: contrast and density; minimal projection geometry: geometric sharpness, motion unsharpness and screen unsharpness; anatomical accuracy; adequate coverage of the anatomical area of interest
What is radiographic density, and what does is depend upon?
the degree of blackness on the film, it depends on the amt of radioation, (greater the radiation, the greater the density); high density = dark film; low density = light film; visible detail is not possible without density
What should be visible with the correct radiographic density?
faint outline of soft tissue, long with the hard tissues.
What is the useful range of film density?
0.3 (very light) to 3.0 (very dark); beyond these extremes, the image is usually too dark or too light to be diagnostically useful.
What are the 3 primary factors that control radiographic density?
-mA (# of e-'s); the higher the mA (current and exposure time) the greater the density
-kVp (speed of the e-'s); higher the kVp the greater the density.
source-film distance (inverse square rule); increase the source-film distance = decrease the density by the square of the distance.
What are the 5 secondary factors that control radiographic density
-Development conditions (increased time = higher density and fog)
-film type (high speed req's less mA to produce a density change)
-intensifying screens (higher speed film req's less mA's)
-grids (decrease scatter; increase exposure); req's more mA to keep density constant
-object density (increase exposure if amalgam present, etc.)
What is radiographic contrast? What is contrast primarily affected by?
the differences in the densities of the film; primarily affected by kVp.
High contrast means X shades of gray?
x=few
Low contrast means X shades of gray?
x=more
long scale means x contrast? What is the ramification of the kVp?
x= low; higher kVp=more penetrating x-rays, density differences are small, so contrast is low. (Few blacks and whites with more shades of gray)
short scale means x contrast? what is the ramification of the kVp?
x=high; lower kVp= less penetrating x-rays, density differences are large=high contrast; more blacks and white and fewer shades of gray.
What kind of contrast should PA's and BW's have?
PA= relatively low contrast
BW= relatively high contrast
What happens is kVp is increased?
the mA or exposure time must be decreased to maintain the previous radiographic density.
What will result from a change in contrast?
Altered film density (kVp affects both the speed and the number of x-rays produced)
Whill a change in density by changing mA only result in an obvious change in contrast?
No
What does image sharpness measure?
how well a boundary b/w two areas of differing radiodensity is revealed
Geometric charactaristics:

image unsharpness can be due to what 3 things?
1. geometric unsharpness
2. motion unsharpness
3. screen unsharpness
what is geometric unsharpness?
diffusion of detail
what is penumbra?
unsharp margin surrounding the image
what causes penumbra?
as the x-rays originate from the focal spot and travel in straight lines, their projections do not occur at exactly the same location of the film
will objects further from the film be magnified or minimized more than objects closer to the film with similar technique?
magnified
image unsharpness, distortion and magnification occurs due to what 3 reasons?
1. x-rays originate from an area rather than a point
2. x-rays travel in diverging straight lines as the radiate from the source
3. human structures have depth, width and length
what are the 5 rules for accurate image formation?
to minimize loss of image clarity:
1. effective focal spot should be as small as possible
2. distance b/w the focal spot and the object should be as long as possible
3. film should be as close to the object as possible
4. long axis of the object should be parallel to the film
5. CR should be perpendicular to the film to record the structures in their ture spatial relationshop
what characteristics are present with a small focal spot?
smaller penumbra, and higher image definition.
what is the significance of object-film distance?
-longer the object-film distance, the greater the unsharpness
-objects closer tot he film have relativley sharper image
-lingual cusps are sharper as they are closer to the film
waht is the the significance of source-object distance?
-radiographic image magnification can be decreased by using longer source-object distnce and shorter object-film distance
-longer BIDs are recommended because of greater anatomical accuracy
how can shape distortion be minimized?
by using the paralleling technique; inherent shape distortion problems arise with the bisecting the angle tech.
the greatest radiographic anatomic accuracy occurs when __________?
1. proximal contacts are opened
2. buccal and lingual cusps of post teeth are superimposed
3. buccal and lingual portions of the alveolar crest are superimposed
4 no superimposition of zygomatic arches over the roots of maxillary teeth
adequate coverage of the area of interest depends on what factors?
1. proper alignment of film and radiation beam to the area of interest
2. proper selection of film type
3. proper selection of film-projection technique.
What are some common errors in intraoral radiography?
-Technique errors
-Exposure Errors
-Processing errors
-film handling errors
Why should we avoid films that lack diagnostic quality?
-Avoid unnecessary pt exposure
-wastes time
-wastes film
-interferes with accurate radiographic interpretation
What are some common technique errors?
Film placement, double exposure, cone cutting, pt movement, overlap, reversed film, vertical angulation, failure to remove appliances, and others
what generally happens if the pt is not biting on the bite block?
the apices of the teeth will be cut off (underangulation)
what is fog? Why does it occur?
unwanted blackness: may occur due to light leaks in the darkroom, unsafe safe light, over-exposure, expired film, chemical fog from over development
what is cervical burnout?
RL areas at the neck of a tooth (can be confused with caries)
What is the normal level of alveolar bone?
Alveolar crestal bone is normal 1.5-2mm from the CEJ
what is the normal bone pattern for the maxilla?
Anterior: thin and numerous trabeculae, forming a fine, rounded, dense pattern, smaller bone marrow spaces.

Posterior Maxilla: similar to anterior, but larger bone marrow spaces
what is the normal bone pattern for the mandible?
anterior mandible: thicker trabeculae, forming a coarser pattern, bone marrow spaces may be rounded.

Posterior mandible: larger bone marrow spaces, mainly horizontally oriented trabeculae, area just below the molar roots may be devoid of trabeculae.
what attaches to the genial tubercles or the mental spines?
the genioglossus and geniohyoid mm's
What are the characteristics of panoramic radiography?
Extraoral technique (film & source located extraorally)
Indirect Film exposure, Image of the facial structures is made on one film, provides a flat picture of a curved layer of oral and maxillofacial structures.
What is used for proper pt positioning in panoramic radiography?
Mid-sagittal plane light, Canine light (placed at the mesial of the maxillary canine), and the FH plane light
How does the film and x-ray source move in pano radiography?
The film and source move simulataneously, but in opposite directions.
what are some advantages of panoramic radiography?
Simple to perform, broad anatomical coverage, low pt dose, short imaging time, readily available in most dental offices, useful as a screening tool, may provide insight or assist in determing the need for other projections, minimal infection control req'd, eval of development, trauma, impacted teeth & pathology, well accepted by pt's
What are the disadvantages of panoramic radiography?
lack of fine anatomical detail, overlapping structures, magnification (20-30%), pt positioning is important, initial expense is more, artifacts, ghost images, and incorrect interpretation.
What is the vertical beam angulation in pano radiography?
-7 to -10 degrees, and it rotates in a horixaontal plane around a rotational center (the occlusal plane)
what is the rotation center?
an invisble, intraoral location where the x-rays appear to diverge from and intraoral source.
what is important about the speed of the x-ray source and the film?
the speed of the two must match
What is the movement pattern of the beam?
this is the pattern chosen to obtain a favorable porjection of the object, is is a curved path that utilizes a contunously moving roation center in which the x-ray beam shifts along this path. It results in a continuous image
T/F there are different pano machines that utilize different techniques
true: different machine utilize different #'s of rotation centers, etc.
What is important about the projection in the vertical plane in pano radiography?
The verical dimension is a result of conventional radiographic projection, it is unaffected by the horizontal rotation of the beam, and the focal spot is the same as conventional intraoral radiography (anode)
What is important about the projection in the horizontal plane in pano radiography?
Horizontal dimension of the image is affected by the horizontal rotation of the beam (this is why the speed is important), in the horizontal dimension, the x-rays appear to diverge from the rotation cener
what happens if the film is not moving, or it is not moving as fast as the source?
horizontal magnification
whaay doe we not use a rotating narrow beam with stationary film in a pano?
horizontal magnification
the film moves in the ____ direction to the horizontal rotation of the beam
opposite
film speed is adjusted to reduce ____ ______?
image magnification
what is the focal trough?
the imaginary plane with the maximum zone of sharpness (where the vertical and horizontal magnification match)
what represents the focal spot on the pano machine?
the notch for the teeth in the bite block
what do objects outside of the focal trough look like?
they may be blurred, magnified, or reduced in size.
what does the focal trough/image layer depend upon?
the distance from the center of roation to the central plane of the image, which is called the "effective projection radius"

The layer thickness is inversely proportional to the width of the long narrow slit beam (narrower the beam, the wider the image layer)
In pano radiography:
The longer the radius, the ____the image layer.
The narrower the beam, the ____ the image layer
thicker

wider
The focal trough is ______ in the anterior region and ______ in the posterior region
narrow in anterior
thicker in posterior
when an object is displaced to the LINGUAL side of the focal trough, toward the source, the beam passes more SLOWLY through the object compared to the film speed and how does the structure appear?
Elongated horizontally, short fat teeth
when the object is displaced toward the BUCCAl the focal trough is closer to the film, and the beam passes at a FASTER rate compared to the film, and how does the structure appear?
Verfical magnfication (long, skinny teeth)
what must you take into account when making measurements on panos?
25-30% magnification, which varies from machine to machine and position of objects in the arch and in the focal trough
What are the concepts of pano radiography that must be understood fro proper interpretation?
Images are viewed as if they are split vetically down the mid-sagittal plane and folded outwards, so structures are flattened and spread out
what happens if the pt is positioned undesirably in the pano machine?
certain stuctures will be flattened and spread out althought hey normally would not be.
when are real images formed?
when the object is located between the rotation center of the beam and the film
when are double real images formed?
when midline objects occur within the diamond-shaped area and the oject is located between the beam and the film twice (2 passes)
what stuctures normally form double real images?
hard and soft palate, palatal tori, body of the hyoid, epiglottis, c-spine
when are ghost images formed?
when the object is located b/w the source and the center of the roation or the object is behind the rotation center.
what are some characteristics of ghost images?
same general shape as its counterpart (no mirror image), formed on opposite side, appears higher on the film than the real structure, blurred and magnified
what are some characterisics of double real images?
one image is mirror image of the other, both are real, each image will have the same properties and location on the opposite side
what structures generally from ghost images?
c-spine, horns of the hyoid, ramus of mandible, hard palate, neck chains, earrings, nechlaces or markers?
T/F some soft tissues attenuate the beam enough to become visible on the radiograph of a pano
True; some examples: post/superior edentulous regions, fluids, cartilaginous tissues like the nose, ear, epiglottis, soft palate, uvula, dorsum of tongue, lips, nasolabial fold, turbinates, septum, posterior pharyngeal wall, and the palatine tonsils
What are the characteristics of air spaces?
does not attenuate the beam, appear black,
what air spaces are often seen on a pano?
nasopharyngeal, oropharyngeal, palatoglossal, hypopharynx, maxillary sinus and nasal fossa
which air space is an error?
the palatoglossal; can change by getting pt to put tongue on roof of mouth
T/F machine and pt components cannot produce single and or double real images ando or ghost images
false
To understand and separate multiple density changes, one must remember what concepts?
air obscures hard tissues, soft tissues obscure air, hard tissues obscure soft tissues, and ghost images obscure everything!!
Why are panos unique?
Helpful in assessment and interpretation, broad anatomical coverage, depict angular interrelationships of structures, and are excellent projection of a variety of structures on a single film
what is the buccal object rule?
Same lingual, opposite buccal; when trying to localize an object, buccal objects appear to move in the opposite direction relative to the direction that the tube moves.
what is the buccal object rule used for?
pathologies, impacted teeth, supernumerary teeth, fractures, and foreign bodies
what is the right angle technique?
method for determining the facial/lingual postion of teeth or foreign objects; two radiographs are taken at right angles to each other, first is PA or BW and second is generally an occlusal projection
What is zone 1 of a pano?
the dentition, a smile-like upward curve, interocclusal space, crowns and roots can be visualized.
what is zone 2 of a pano?
nose and sinus; inferior turbinates and meati within the nasal cavity; hard palate image whithin the sunuses, above the apices, no air spaces shadow over the apices!!
what is zone 3 of a pano?
Mandibular body; cortex smoth and continuous, no ghost image superimpostion (hyoid bone)
what is zone 4 of a pano?
TMJ; centered; not cut-off and equal in size bilaterally
what is zone 5 of a pano?
Ramus-Spine; same width bilaterally, spine may not be seen. If observed, equal distance b/w sping and ramus, spine should not be superimposed over ramus
what is zone 6 of a pano?
Hyoid: double image, equal in size bilaterally, and no ghost image formation over the body of the mandible.
what are the steps in exposing a pano film?
review medical hx, check the radiology log, room prep, set the exposure factors, pt prep, pt positioning, exposure, processing
What is the region of improved imaging if the pt is too far forward in a pano?
nasal fossa and sinus
what is the region of improved imaging if the pt's chin is too low in a pano?
anterior maxilla and teeth
what is the regio nof improved imaging if the chin is too high in a pano?
anterior mandible and teeth