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SU14 - Radiology Final Exam > su14_-_radiology_final_exam_20141210195330 > Flashcards

su14_-_radiology_final_exam_20141210195330 Flashcards

1
Q

For intraoral dental equipment, according to the State of Ohio, the source-to-skin distance (SSD) is not to be less than ____ cm if operable above 50 kVp or ____ cm if operable at 50 kVp.

A
  • 18 cm- 10 cm
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2
Q

For intraoral dental equipment, according to the State of Ohio, x-ray field at the minimum SSD (source-to-skin distance) shall be containable in a circle having a diameter of no more than ____ cm if operable at or above 50 kVp.

A

7 cm

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3
Q

For intraoral dental equipment, according to the State of Ohio, a means shall be provided to terminate the exposure at a preset ____ or ____ or ____ or ____.

A
  • time interval- product of current and time- number of pulses- radiation exposure to the image receptor
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4
Q

For intraoral dental equipment, according to the State of Ohio, the operator shall be able to ____ the exposure at any time during an exposure of greater than ____ second(s).

A
  • terminate- one-half second
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5
Q

For intraoral dental equipment, according to the State of Ohio, the kVp accuracy shall be within plus or minus ____ % of the indicated value.

A

10%

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6
Q

For intraoral dental equipment, according to the State of Ohio, for manual exposures, the accuracy of the ____ device shall be within plus or minus ____ % of the indicated setting.

A
  • timing device- 10%
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7
Q

For intraoral dental equipment, according to the State of Ohio, ____ indication shall be provided whenever x-rays are produced. Certified equipment also shall provide ____ indication to the operator while x-rays are produced or on termination of the exposure.

A
  • visual- audible
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8
Q

For intraoral dental equipment, according to the State of Ohio, the coefficient of variation for reproducibility of ____, ____, and ____ shall not exceed ____ for four consecutive exposures.

A
  • kVp- timing- radiation exposure- 0.05
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9
Q

For shielding requirements, according to the State of Ohio, ____ and ____ units shall be provided with primary barriers at all areas struck by the useful beam.

A
  • intraoral- panoramic
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10
Q

For shielding requirements, according to the State of Ohio, when intraoral or panoramic units are in ____, protective barriers shall be provided between the rooms or areas.

A

adjacent patient occupied rooms or areas

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11
Q

For protection, according to the State of Ohio, no individual shall be permitted to hold ____ during exposure.

A

any part of the x-ray tube housing, cone, or mechanical support of the x-ray tube

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12
Q

For protection, according to the State of Ohio, each installation of an x-ray unit shall provide a protective barrier for the operator or shall be arranged so that the operator stands at a minimum distance of ____ feet from the patient and out of the useful beam.

A

six

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13
Q

For panoramic x-rays, according to the State of Ohio, dental panoramic x-ray machines shall be ____.

A

certified

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14
Q

For panoramic x-rays, according to the State of Ohio, when the operator is behind a protective barrier, a ____ shall be provided large enough and so placed that ____.

A
  • a viewing system- the operator can see the patient without having to leave the protected area during exposure
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15
Q

For panoramic x-rays, according to the State of Ohio, x-ray field shall be limited to the dimensions of ____.

A

the slit in the image receptor holder

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16
Q

According to the State of Ohio, what type of imaging is not allowed for use in dental examinations?

A

fluoroscopy

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17
Q

For sectional imaging, according to the State of Ohio, handlers of radiation-generating equipment capable of sectional imaging, used only for dental procedures, shall comply with ____ and be included in the ____.

A
  • all manufacturer’s specifications- registrant’s quality assurance plan
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18
Q

For hand-held equipment, according to the State of Ohio, hand-held radiation generating equipment shall be used for ____ only.

A

intraoral

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19
Q

For hand-held equipment, according to the State of Ohio, operators of the hand-held radiation-generating equipment shall wear ____.

A

a full lead apron of not less than 0.25 mm lead equivalent

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20
Q

For hand-held equipment, according to the State of Ohio, ____ for the hand-held radiation-generating equipment shall be in place during all radiographic exposures.

A

back scatter shield

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21
Q

For hand-held equipment, according to the State of Ohio, all operators of hand-held radiation-generating equipment shall be provided and wear a ____ in order to ____. The operator must wear the ____ on the ____.

A
  • personnel dosimeter- monitor the dose to the operator’s hand- personnel dosimeter- hand holding the beam limiting device
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22
Q

For hand-held equipment, according to the State of Ohio, storage and security procedures shall be developed and implemented to assure hand-held radiation-generating equipment is secured against ____ or ____ when not under the control and constant surveillance of the registrant.

A
  • unauthorized use- removal
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23
Q

For hand-held equipment, according to the State of Ohio, ____ specific to the hand-held radiation-generating equipment shall be developed and implemented.

A

safe operating procedures

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24
Q

For hand-held equipment, according to the State of Ohio, operator training shall include ____.

A

documented specific instruction to the x-ray operator regarding the prohibition on placing any part of their body into the useful beam

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25
Q

According to the State of Ohio, dental equipment with nominal fixed kVp of less than ____ shall not be used to make diagnostic dental radiographs of human beings.

A

50

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26
Q

The NCRP (National Council on Radiation Protection) #145 was released in December 2003 recommending ____ for children (and for adults) and ____ collimation.

A
  • thyroid collar- rectangular
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27
Q

True or false: The ADA recommends a lead apron and thyroid collar for only children.

A

FALSE. They recommend it for all patients.

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28
Q

The NCRP #145 did not recommend ____-speed film and instead, recommended ____-speed film or faster.

A
  • D-speed- E-speed
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29
Q

The NCRP #145 recommended rare earth screens for ____ radiography. They also recommended for shielding design for new or remodeled dental offices to be done by ____.

A
  • extraoral radiography- a qualified expert
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30
Q

The NCRP #145 did not recommend ____ development. They did recommend ____ for all pregnant personnel.

A
  • sight development- film badges
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31
Q

What is panoramic radiography?

A

a technique for making detailed radiographs of a plane section of a solid object while blurring out the images of adjacent planes

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32
Q

What is body section radiography?

A

a radiographic technique in which the film and x-ray tube are moved in opposite directions to produce a more distinct image of a selected body plane

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33
Q

What is focal trough/image layer?

A

a 3D curved zone in which structures are reasonably well-defined

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34
Q

A panoramic image is obtained by rotating a narrow beam of radiation in the ____ plane. The image receptor is rotated in ____ (the same/different) direction while the object (jaws) is ____.

A
  • horizontal- the same- stationary
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35
Q

Vertical magnification in panoramics varies ____ (a little/a lot) with object depth (focal spot to object distance).

A

a little

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36
Q

True or false: Horizontal magnification of panoramics is the same for the anterior and posterior region.

A

FALSE. It varies in the anterior and posterior region because of the two centers of rotation (anterior and lateral centers of rotation).

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37
Q

Horizontal magnification in panoramics varies ____ (a little/a lot) with object depth (focal spot to object distance).

A

a lot

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38
Q

Ghost images in panoramic radiographs arise from structures located where?

A

on the posterior aspect of the opposite side

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39
Q

Where are ghost images projected in relation to the real object?

A

projected on the opposite side of corresponding real image higher than the real object

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40
Q

What are the steps for panoramic radiography?

A
  • set exposure factor- have patient removal metallic objects from head and neck area- have the patient wear the radiation protection apron plus thyroid shield in pediatric patients- walk patient into machine- have patient bite on bite stick- have patient stand up straight- position the ala-tragus line- position the lateral guide- have patient swallow, place tongue in roof of mouth and hold still- make exposure
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41
Q

The panoramic radiograph is light/pale film with few dark areas. What is the cause of this problem and how can it be corrected?

A
  • too little exposure- increase mA or kVp or use next higher setting on machine*also, rule out worn-out or reversed screens
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42
Q

The panoramic is dark film with loss of details and amalgams and unexposed areas are still clear. What is the cause of this problem and how can it be corrected?

A
  • too much exposure- decresae machine settings*don’t confuse with film fogging which is an overall grayness to film
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43
Q

The panoramic has white opacities on film and little or no image is visible on the film. What is the cause of this problem and how can it be corrected?

A
  • ghosts of metal jewelry- remove prior to exposure*watch out for necklaces
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44
Q

The panoramic has a white opacity in the palate. What is the cause of this problem and how can it be corrected?

A
  • tongue bar- remove prior to exposure*image is projected high onto palate instead in floor of mouth
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45
Q

The panoramic has a white opacity at the bottom of the film shaped like an inverted “v” or “shark fin”. What is the cause of this problem and how can it be corrected?

A
  • lead apron above collar line and in x-ray beam- adjust and properly place apron*watch for bunching at back of neck
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46
Q

What type of magnification occurs in the center of the focal trough?

A

Trick question! No magnification (horizontal or vertical) magnification in the focal trough so there is no distortion.

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47
Q

True or false: No image distortion occurs outside the focal trough.

A

FALSE. Image distortion occurs outside the focal trough, not in it.

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48
Q

The panoramic has anterior teeth that are blurry, too small and narrow, and spine visible on the sides of the film. What is the cause of this problem and how can it be corrected?

A
  • patient biting too far forward on bite rod- make sure anterior teeth are located in grooves on rod*make sure mandibular incisors are in groove also and bite rod is not being bent forward
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49
Q

The panoramic has anterior teeth blurry and wide with ghosting of the mandible and spine and condyles that are close to the edge of the film. What is the cause of this problem and how can it be corrected?

A
  • patient is biting too far back on rod or not at all- make sure anterior teeth are located in grooves on rod*if anterior teeth are missing, use edentulous guide
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50
Q

The panoramic has roots of lower incisors blurry, the mandible is shaped like a “v”, there is too much smile line, the condyles are at the tope of the film, and spine forms an arch or “gazebo effect”. What is the cause of this problem and how can it be corrected?

A
  • patient’s chin is tipped too far down- reposition using proper guidelines for that machine, such as alar-tragus line*make sure patient does not have unusual occlusal plane orientation
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51
Q

The panoramic has maxillary incisors blurry, hard palate superimposed on roots, flat occlusal plane, mandible is broad and flat, and condyles are at the edge of the film. What is the cause of this problem and how can it be corrected?

A
  • patient’s chin is tipped too far up- reposition using proper guidelines for that machine such as alar-tragus line*make sure bite rod remains seated in its guide
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52
Q

The panoramic has teeth that are wide on one side, narrow on other side of midline, ramus that is wider on one side than on the other, uneven pattern of blurring throughout arch, and nasal structures are not clear. What is the cause of this problem and how can it be corrected?

A
  • patient’s head is twisted in machine causing midline asymmetry- reposition using proper guidelines for that machine*make sure patient doesn’t try and look toward technician but straight ahead; always use front-surface mirror on machine to check alignment
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53
Q

The panoramic has condyles that are not equal in height and nasal structures that are distorted. What is the cause of this problem and how can it be corrected?

A
  • patient’s head is rotated in machine (tipped)- reposition using proper guidelines for that machine*make sure patient’s head remains level through ears
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54
Q

The panoramic has white tapered opacity in the middle of the image (in the shape of the Washington monument). What is the cause of this problem and how can it be corrected?

A
  • ghost of spinal column due to slumping- have patient take a step forward and straighten neck*don’t allow patient to reach forward into machine; make them step forward
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55
Q

The panoramic has dark vertical line extending from the top to bottom edge of the film. What is the cause of this problem and how can it be corrected?

A
  • cassette hit shoulder and temporarily slipped- straighten neck; check apron for interferences*have patient keep elbows tucked in to sides to reduce shoulder height
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56
Q

The panoramic has a large dark shadow over the maxillary teeth between the palate and dorsum of the tongue. What is the cause of this problem and how can it be corrected?

A
  • patient’s tongue not in the roof of mouth- instruct patient to place tongue in the roof of mouth prior to exposure*having patient swallow first can make it easier for them to obtain proper tongue position
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57
Q

The panoramic has portions of the radiograph blurred with large step defects in inferior border of the mandible. What is the cause of this problem and how can it be corrected?

A
  • patient moved during the 15 seconds of exposure time- instruct patient to hold still prior to exposure*tell patient exposure will last 15 seconds so they will expect it
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58
Q

How does exposure change with an obese patient? With a patient with a large bone structure?

A

use the next highest kVp or mA setting for both

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59
Q

How does exposure change with a patient with a small bone structure? A patient that is edentulous?

A

use the next lower kVp or mA setting for both

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60
Q

What are the advantages (6) of panoramic radiography?

A
  • large size (helpful in visualizing the maxilla and mandible plus teeth and associated structures)- approximate measurement of large lesions (ex. cysts) is possible- simplicity- time- 20% less dose than a full mouth series using F-speed film- patient comfort/cooperation
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61
Q

What are the disadvantages (8) of panoramic radiography?

A
  • image quality (magnification, geometric distortion, and poor definition)- magnification (about 20-32% due to external placement of image receptor and an increased object to image receptor distance)- limited use in caries diagnosis, evaluation of periodontium, periodontal defects, and root canal measurements- focal trough (image layer) (structures outside the focal trough are poorly visualized or not seen at all)- overlap- superimposition- ghost images- overuse
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62
Q

Who invented Computed Tomography (CT)?

A

Sir Godfrey Hounsfield (“father of modern radiology”)

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63
Q

What are the 3 major differences between conventional radiographs and CT?

A
  • convention radiographs give a 2D image while CT gives multiplanar and cross-sectional images and 3D viewing- conventional radiographs give superimposed images while CT has no superimpostion- conventional radiographs have a low sensitivity due to scatter while CT has many times higher sensitivity to subtle differences
64
Q

What was the principle of the first CT scanner?

A

internal structures of an object can be reconstructed from multiple projections of the object

65
Q

How is an image acquired in a CT scanner?

A

x-ray tube is rotated around the patient; radiation transmitted through the patient is absorbed by a ring of detectors; absorbed radiation is converted to an image

66
Q

What is the current standard for a CT scanner? How many slices? How many cm vol lengths in how many seconds? What type of resolution?

A
  • multidetector CT- up to 64-slice scanners- can scan more than 40 cm vol lengths in 30 seconds- isotropic resolution
67
Q

What is isotropic resolution?

A

all sides of a box have the same dimensions; gives clearer images that are more realistic

68
Q

What are the limitations of fan-beam CT in dentistry?

A
  • expensive- substantial size; occupy a large space- high radiation dose
69
Q

What is the difference in image acquisition configuration of a fan beam CT vs. cone beam CT?

A
  • fan beam has multiple rotations of 360 degrees- cone beam has single rotation of 360 degrees
70
Q

What is the difference in detector of a fan beam CT vs. cone beam CT?

A
  • fan beam has scintillator detector array- cone beam has an image intensifier coupled to CCD or flat panel detector
71
Q

What is the difference in x-ray tube of a fan beam CT and a cone beam CT?

A
  • fan beam has medical type (higher output)- cone beam has generally dental type (lower output)
72
Q

How is an image taken in cone beam computed tomography (CBCT)?

A

a cone-shaped x-ray beam is directed through the middle of the area of interest (patient) onto an area x-ray detector (sensor) on the opposite side; the x-ray source and detector rotate around a rotation fulcrum fixed within the center of the region of interest; during the rotation, multiple (from 150 to 600+) sequential planar projection images of the field of view (FOV) are acquired in a complete or sometimes partial arc

73
Q

For cone beam computed tomography (CBCT), what is a small field of view?

A

localized region - approximately 5 cm or less (ex. dentoalveolar, temporomandibular joint)

74
Q

For cone beam computed tomography (CBCT), what are medium fields of view (2)?

A
  • single arch: 5-7 cm (ex. maxilla/mandible)- interarch: 7-10 cm (ex. inferior concha to mandible)
75
Q

For cone beam computed tomography (CBCT), what are large fields of view (2)?

A
  • maxillofacial: 10-15 cm (nasion to mandible)- craniofacial: greater than 15 cm (ex. vertex of skull to inferior border of mandible)
76
Q

What are the advantages (12) in dental/maxillofacial imaging AKA cone beam computed tomography (CBCT)?

A
  • small footprint- 1/4 to 1/5 the cost of conventional fan beam CT- rapid scan time- beam collimation- accurate image (isotropic)- significantly reduced patient exposure (*!)- display modes applicable to maxillofacial imaging- MPR- ray sum- curved MPR- 3D volume rendering- segmentation
77
Q

What are the disadvantages (5) of CBCT?

A
  • artifacts (x-ray beam, patient related, scanner related, cone beam related, partial volume averaging)- undersampling- image noise- poor soft tissue contrast- cost?
78
Q

What are some applications (8) of dental and maxillofacial imaging (CBCT)?

A
  • analysis of available bone for implant placement- preoperative assessment of impacted teeth- assessment of bony and dental pathologic conditions, including fracture- structural maxillofacial deformity- temporomandibular joint imaging- 3D cephalometry- evaluation of root canal system- evaluation of nasopharyngeal airway
79
Q

What are the 3 steps of the MRI process?

A
  • magnetic field: nuclei of many atoms, particularly hydrogen, align with an external magnetic field (MRI machine)- radio-frequency pulse: generated by “transmitter coil” directed at a patient cause some hydrogen nuclei to absorb energy- relaxation: when RF pulse is turned off, the stored energy is released from the body and detected as a signal in “receiver coil”*signal is essentially a map of hydrogen ion distribution in the body
80
Q

Rank these tissues from white to black in terms of their appearance in an MRI.TMJ diskmarrowfatbody fluidaircortical bonemusclebrain

A

(white)fatmarrowbrainmusclebody fluidTMJ diskcortical boneair(black)

81
Q

True or false: The terms radiolucent and radiopaque can be used to describe the darkness of objects in an MRI.

A

FALSE. There is no radiographs in MRIs so those terms do not apply.

82
Q

What are the advantages (3) of MRIs?

A
  • high soft tissue resolution- non-invasive- multiplanar imaging
83
Q

What are the disadvantages (4) of MRIs?

A
  • high cost- long imaging time- hazards with ferromagnetic metals (pacemakers, vascular clips, etc.)- claustrophobic design
84
Q

What are MRIs used for in the maxillofacial region?

A
  • TMJ imaging- soft tissue disease such as neoplasia
85
Q

Nuclear medicine is used to show the ____ and ____ of the target tissues using what kind of scans?

A
  • structure- function- scintigraphy or radionuclide scans
86
Q

How is an image taken using nuclear medicine?

A

radioactive compounds such as Technetium are injected into the body and taken up by “active” tissues; radioactive agents pool in the target tissues and give off radioactivity; detected and imaged by external detectors

87
Q

What are applications of nuclear medicine imaging in the maxillofacial region?

A
  • bone imaging- soft tissue imaging (salivary gland, lymph node)
88
Q

What type of beam is used for ultrasonography?

A

sound beam

89
Q

What does an x-ray need for propagation? What does sound need for propagation?

A
  • x-ray: vacuum- sound: medium
90
Q

Rank these in order of which medium sound travels through fastest to slowest.bonefatsoft tissuesairmetalmusclebloodwater

A

(fastest)metalbonemusclebloodsoft tissuesfatwaterair(slowest)

91
Q

What are the components of an ultrasound unit?

A
  • transducer- CPU- display- printer
92
Q

How does an ultrasound transducer work?

A
  • converts one form of energy to another: electrical signal to sound and then sound echo back into electrical signal- same transducer acts as a transmitter as well as a receiver- cannot transmit and receive at the same time
93
Q

What do high density structures (hard tissues) appear as in conventional radiographs? In computed tomography and cone beam CT? In MRI? In ultrasonography?

A
  • conventional radiographs: radiopaque- CT: high-attenuation (or radiopaque)- MRI: low-signal (dark)- ultrasonography: hyperechoic (white)
94
Q

What do low density structures (soft tissues) appear as in conventional radiographs? In computed tomography and cone beam CT? In MRI? In ultrasonography?

A
  • conventional radiographs: radiolucent- CT: low-attenuation (or radiolucent)- MRI: high-signal (white)- ultrasonography: hypoechoic (dark)
95
Q

What are the 3 types of images seen in panoramic radiographs?

A
  • single real images- double real images- ghost images
96
Q

What is the definition of a single real image in a panoramic radiograph?

A
  • only one image results from a given anatomical structure- the structure is located between the rotation center and film; x-ray beam only passes through the structure one time
97
Q

Most images seen on a panoramic radiograph are ____ (single or double real images)

A

single real images

98
Q

What is the definition of double real images?

A
  • two images of a single object are seen on the radiograph- produced by structures that are located in the midline- the x-ray beam passes through these objects twice as the tubehead rotates around the patient
99
Q

What are some of the structures that result in double real images?

A
  • hard and soft palate- hyoid bone- cervical spine
100
Q

What is the definition of ghost images?

A
  • formed by dense objects located between the tubehead and the rotation center- these ghost images usually result from external objects such as earrings, but they may be produced by dense anatomical structures such as the mandible
101
Q

What anatomical structure is described below?- palatal to incisors- pear-shaped opening- nasopalatine nerve and vessels

A

incisive foramen

102
Q

What anatomical structure is described below?- palatal- radiolucent line- present between two processes- runs posteriorly from alveolar crest

A

median palatine suture

103
Q

What anatomical structure is described below?- v-shaped projection viewed in periapical and occlusal images- present in midline apical to central incisors- radiopaque - sometimes obscured by superimposition of other structures

A

anterior nasal spine

104
Q

What anatomical structure is described below?- appears more radiolucent than surrounding bone- canine eminence adjacent to the border of nasal fossa- could be mistaken for periapical pathology

A

canine fossa

105
Q

What anatomical structure is described below?- air-containing cavity in maxilla (radiolucent)- margins are made by thin layer of dense bone (radiopaque)- also known as “antrum”

A

maxillary sinus

106
Q

Anterior border of maxillary sinus often intersects a line formed by ____.

A

the floor of the nasal fossa

107
Q

Posterior and inferior border of maxillary sinus will often appear to involve the ____.

A

roots of maxillary premolars and molars

108
Q

What anatomical structure is described below?- quadrangular cheek bone extends laterally from maxillar and is superimposed over the roots of maxillary posterior teeth- only the inferior portion is visible on periapical radiographs

A

zygomatic bone

109
Q

What anatomical structure is described below?- an important landmark for determining the posterior boundary of upper denture- marks posterior limit for molar periapical image receptor placement

A

maxillary tuberosity

110
Q

What anatomical structure is described below?- a hook-like process arising from the inferior tip of medial pterygoid plate- posterior boundary of pterygomaxillary fissure - muscle attatchment

A

pterygoid hamulus

111
Q

What anatomical structure is described below?- insertion point for the temporalis and masseter muscle- form anterior boundary of mandibular or sigmoid notch- often overlap maxillary tuberosity (area appears radiopaque)

A

coronoid process of mandible

112
Q

What is the only mandibular structure showing on a maxillary periapical?

A

coronoid process

113
Q

Generally the hard tissues of the mandible are ____ (more/less) distinct on the radiographs as there is ____.

A
  • more distinct- less soft tissue to attenuate the x-ray beam on intraoral images
114
Q

What anatomical structure is described below?- thick cortical bone of the mandible; appear as dense radiopaque structure- viewed in posterior radiographs or in radiographs with excessive angulation

A

inferior border of mandible

115
Q

What anatomical structure is described below?- radiolucent area overlying mandibular incisors- could be mistaken for pathological lesion

A

labial depression

116
Q

What anatomical structure is described below?- a midline circle surrounded by genial tubercles, sometimes seen in incisor periapical images- allow passage of arteries branching from sublingual artery; radiolucent area

A

lingual foramen

117
Q

What anatomical structure is described below?- also called mental spines- located on lingual surface of the body of mandible at midline- genioglossus and geniohyoid muscles are attached to upper and lower portions, respectively- midline radiopaque structure

A

genial tubercles

118
Q

What anatomical structure is described below?- usually located between first and second premolars- allow passage of mental vessels and nerve- representation by a radiolucent area

A

mental foramen

119
Q

What anatomical structure is described below?- extend obliquely upwards from just above the digastric fossa along the medial surface to the anterior border of ramus- give origin to mylohyoid muscle and other muscles in the floor of the mouth

A

mylohyoid ridge (internal oblique ridge)

120
Q

What anatomical structure is described below?- commence at the mandibular foramen in ramus and pass downwards and forward- appear as a narrow dark ribbon between two white lines apical to posterior teeth

A

mandibular canal

121
Q

What anatomical structure is described below?- this depression along the medial surface of mandible below mylohyoid ridge- radiolucent appearance which can be mistaken for pathology

A

submandibular fossa

122
Q

What anatomical structure is described below?- show as radiopacity on posterior periapical images- a barrier to proper image receptor placement; they may appear superimposed on the antrumand apices of maxillary posterior teeth

A

palatal torus

123
Q

What anatomical structure is described below?- radiopacities seen in mandibular periapical images- they usually occur in pairs; compare with the image on the opposite side

A

lingual tori

124
Q

What planes can be seen in 2D radiological images? In 3D?

A
  • 2D: superior-inferior and mesial-distal- 3D: superior-inferior, mesial-distal, and anterior-posterior
125
Q

What happens when a CBCT (cone beam CT) scan is acquired?

A

basis projections (takes individual image at each of 360 degrees) and scans top to bottom

126
Q

What is the most common way to look at a CBCT?

A

2D reconstruction

127
Q

Dental caries are a bacterial infection caused by what type of bacteria?

A

streptococcus mutans (and others)

128
Q

In a dental caries lesion, there is ___ and ___ of enamel and dentin by bacterial acid products. If it progresses to the pulp, there may be ___ and eventual ___.

A
  • decalcification- cavitation- pulp inflammation- pulp necrosis
129
Q

As caries progress, the ___ content of a tooth decreases so there is ___ (increased/decreased) absorption of an x-ray beam as it passes through the carious region of a tooth so the radiographic image will look ___.

A
  • mineral- decreased- radiolucent
130
Q

When looking at a full mouth series, in what order do you look at the films? In what order do you look at the structures in each film?

A
  • start in upper left and read clockwise, periapicals first and bitewings last- examine bone and bony structures, then alveolar bone, then teeth
131
Q

What are the 4 factors affecting radiographic diagnosis of caries?

A
  • image density and contrast- restorative materials- size of lesion- angulation of x-ray beam
132
Q

What is the best type of radiograph to diagnose caries?

A

bitewings

133
Q

What is the sequence of diagnosing caries?

A
  • visual inspection (including transillumination)- probing (?) (if you probe it, you may disturb remineralization process)- radiographs - for detection and confirmation
134
Q

What are the 3 classification of size of dental caries?

A

incipient, moderate, severe

135
Q

What are the 4 most common locations/types of dental caries?

A
  • occlusal- proximal- cemental/root- recurrent
136
Q

The progression of dental caries includes an initial ___ penetration through enamel that ___ once in dentin. This gives a characteristic ___ shape on a radiographic image.

A
  • linear- explodes- mushroom
137
Q

Where do interproximal caries most often form?

A

gingival to the contact point

138
Q

What is the classic description of the shape of a carious lesion in the enamel (incipient)?

A

chevron

139
Q

What is the definition of mach band?

A

a radiolucent region that appears directly adjacent to enamel due to sharply defined density difference between enamel and dentin

140
Q

What are recurrent caries? What are they due to?

A
  • caries adjacent to a restoration- due to inadequate margins or inadequate excavation
141
Q

True or false: Severe periodontal bone loss makes the root surface less prone to caries.

A

FALSE. makes it more prone

142
Q

What is cervical burnout?

A

diffuse radiolucency with ill-defined borders between the CEJ and alveolar crest; clinical evaluation is sometimes required

143
Q

True or false: For root caries to occur, there almost always needs to be bone loss.

A

true

144
Q

What are the 10 contributions of radiographs in the interpretation of periodontal disease?

A
  • provide information about the status of periodontium- serve as a permanent record of bone condition- adjunct to other diagnostic tools- amount of bone present- condition of alveolar crest- bone level in furcation area- width of periodontal ligament space- local irritating factors increasing risk of periodontal disease- root length and morphology, crown-to-root ratio- other anatomical and pathological conditions
145
Q

What are the 4 limitations of radiographs in assessing periodontal structures?

A
  • 2D view- don’t demonstrate soft tissue-to-hard tissue relationships- show less severe bone destruction than is actually present- possible inaccuracy in bone level measurement in certain situations (if angle isn’t right, etc.)
146
Q

What are the 2 types of bone loss?

A
  • horizontal- vertical
147
Q

What are the 3 classifications of periodontitis in terms of amount of bone loss?

A
  • mild - 20% or less loss of bone height- moderate - 40% or less- severe - more than 40%
148
Q

The distance between the DEJ and the alveolar crest is normal at __-__ mm

A

1.5-2.0 mm

149
Q

A normal alveolar crest should have ___ (bony structure at the top)

A

crestal cortication

150
Q

True or false: The periodontal ligament space is fixed and will never change size.

A

FALSE. It may widen due to inflammation, pulp necrosis, trauma, or a malignant tumor :(

151
Q

What are the 6 clinical features of common periapical pathoses?

A
  • redness- swelling- heat- pain- fever- insignificant clinical symptoms
152
Q

What is a radiolucent periapical lesion called?

A

rarefying osteitis

153
Q

What is a radiopaque periapical lesion called?

A

sclerosing, condensing, or focal sclerosing osteitis

154
Q

What is ostomyelitis?

A

when infection leaves the alveolar bone and infects the basal bone

155
Q

Acute periodontitis can lead to a ____ and ____.

A
  • periodontal abscess- osteomyelitis
156
Q

Chronic periodontitis can lead to ____, ____, and ____.

A
  • periapical granuloma- periapical cyst- osteomyelitis

SU14 - Radiology Final Exam (1 decks)

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