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52 Cards in this Set
- Front
- Back
Lateral cephalometric analysis provides a morphological description of?
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Skeletal & Dental relationships
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What are the measurements compared against in lateral cephalometric analysis?
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“ideals” (Adonis) or “norms” (longitudinal growth studies, cross sectional analysis)
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When do you take cephs in ortho tx?
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prior to comprehensive eval, interim tx (growth, tx effects), post tx
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What do you analyse with a ceph?
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landmarks, planes, measurements
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What is the distance from the x-ray source to the mid-sagittal plane of the patients head when taking a ceph?
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60” (5 ft)
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What is the distance from the mid-sagittal plane of the patients head to the cassette when taking a ceph?
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18 cm from midsagittal (15 cm from side of face to cassette)
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What side of the face is enlarged when taking the ceph?
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the side further away from the film
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Who are the first individuals to establish use of the lateral ceph technique?
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Broadbent & Hofrath
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What are the hard tissue landmarks used when evaluating a ceph?
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Sella (S), Nasion (N), Orbitale (Or), Anteriror Nasal Spine (ANS), Posterior Nasal Spine (PNS), Porion (Po), A point/Subspinale (A), B point/Supramentale (B), Pogonion (Pog), Menton (Me), Gnathion (Gn), Gonion (Go)
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What are the anatomic planes used as reference points when tracing a ceph?
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Sella-Nasion (SN), Frankfort plane, Frankfort Horizontal (FH), Palatal Plane (PP), Functional Occlusal plane (FOP), Mandibular Plane (MP)
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Where is the Sella (S)?
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a cephalomteric hard tissue landmark geometric center of the pituitary fossa (midpoint)
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Where is the Nasion (N)?
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the cephalomteric hard tissue landmark that is the most anterior point of the sagittal JUNCTION of the frontonasal suture
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Where is the Orbitale (Or)?
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a cephalomteric hard tissue landmark located at the lowest point in the inferior margin of the orbit. (if there are two images, it is the midpoint between right and left images)
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Where is the Anteriror Nasal Spine (ANS) ?
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a cephalomteric hard tissue landmark that is the most anterior bony point on the MAXILLA at the base of the nose (anterior point)
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Where is the Posterior Nasal Spine (PNS) ?
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a cephalomteric hard tissue landmark that is the most posterior limit of bony PALATE (palatine bone)
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Where is the Porion (Po)?
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a cephalomteric hard tissue landmark that is the most superior point on the bisected EXTERNAL AUDITORY MEATUS (if cephalostat has metal marker it will be located in this area and be referred to as the “machined porion”)
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Where is the A point (A)? where is it located?
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a cephalomteric hard tissue landmark located on the innermost curvature of the maxilla between ANS and crest of the maxillary alveolar process
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Where is the B point? Where is it located?
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a cephalomteric hard tissue landmark that is the most posterior point of the curvature from the bony chin to alveolar junction
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What is the Pogonion (Pog)?
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a cephalomteric hard tissue landmark that is the most anterior point on the anterior curvature of the mandibular symphysis
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What is the Menton (Me)?
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a cephalomteric hard tissue landmark that is the most inferior point on the mandibular symphysis
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What is the Gnathion (Gn)?
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a cephalomteric hard tissue landmark that is the most outward and everted point on the curvature of the symphysis
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How is the position of the gnathion determined?
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Constructed from the intersecting line drawn perpendicular to the line connecting Menton & Pogonion
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Where is the Gonion (Go)?
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a cephalomteric hard tissue landmark that is the point at the middle of the curvature at the angle of the mandible
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How is the position of the Gonion determined?
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constructed from the intersection of the ramus plane and the mandibular plane
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What is the plane formed by connecting S & N?
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Sella-Nasion (SN) plane
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How is the Frankfort Plane constructed?
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formed from the Porion (upper rim of the external auditory meatus) to the Orbitale (the inferior border of the orbital rim)
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What is the plane formed from connecting ANS to PNS?
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Palatal Plane
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A normal/balanced individual should have a Palatal Plane that is nearly parallel to what other plane?
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Frankfort Horizontal (FH)
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How do you form the Functional Occlusal Plane?
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Trace a line through the distal cusp tip of the maxillary 1st molar and through the occlusal contact of the upper and lower premolars registered at the averaged mesial
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How do you form the Mandibular Plane?
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Draw a line from Gnathion (Gn) to Gonion (Go) tangent (along) to the posterior inferior border of the mandible
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What is Steiner Analysis?
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Cecil Steiner from SoCal had “ideals” based on an individuals measurements in relationship to a pattern set by the relationship measures from the group. It created a baseline guide of standardized measurments for use in cephalometric treatment planning.
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What is the first measurement in Steiner Analysis?
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SNA (angle)
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What does the SNA angle responsible for measuring? and what is the “norm”?
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evaluates the anteroposterior position of the MAXILLA relative to anterior cranial base, the “norm” is 82 plus or minus 2 degrees
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What value would be interpreted as maxillary protrusion, when measuring SNA in Steiner Analysis? Maxillary retrusion?
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greater than 84 degrees for protrusion, less than 80 degrees for retrusion
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What is the second measurement in Steiner Analysis?
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SNB (angle)
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What does the SNB angle responsible for measuring? and what is the “norm”?
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evaluates the anteroposterior position of the MANDIBLE, the “norm” is 80 plus or minus 2 degrees
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What value would be interpreted as mandibular prognathism, when measuring SNB in Steiner Analysis? Mandibular retrognathism?
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greater than 82 degrees for mandibular prognathism, less than 78 degrees for mandibular retrognathism
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What is the third measurement in Steiner Analysis?
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ANB angle
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What is the ANB angle in Steiner Analysis? What does it determine?
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the difference between SNA & SNB angles (angle created by SNA & SNb), used to indicate the magnitude of skeletal jaw discrepancy (more important than which jaw is at fault)
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What is the SN-MP angle in Steiner Analysis? What does it determine?
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mandibular plane angle (at the angle of the mandible), used to establish vertical position of the mandible (long face look, etc)
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What are the two factors that influence the magnitude of the ANB angle?
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1. The vertical height of the face 2. Anteroposterior position of nasion, if abnormal the size of the angle will be affected
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What happens to the ANB angle if the distance between nasion and points A & B increase?
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the ANB angle will decrease
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What is the fourth measurement in Steiner Analysis?
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1-NA (upper incisor to NA)
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What is the fifth measurement in Steiner Analysis?
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1-NB (lower incisor to NB)
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What is the angle of inclination a measurement of in Steiner analysis? how is it formed?
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the angle that indicates the degree that the maxillary or mandibular teeth are tipped, formed from the relationship of the upper incisor to the NA line, and both the lower incisor and chin to the NB line
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When you look at the position of incisor in a mm measurement, what are the proper terms used to describe positional measurement?
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protruded or retruded measurement
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When you look at the position of incisor in an angle measurement, what are the proper terms used to describe positional measurement?
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proclination or retroclination
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What does the millimeter distance from the vertical line to incisal edge determine?
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how prominent the incisor is relative to the supporting bone, indicates whether tooth has been tipped to its position or has moved there bodily
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What does the prominence of the chin (pogonion) compared to the prominence of the lower incisor establish? What is this relationship referred to as?
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balances between how prominent the incisor and chin can be in relation to each other, referred to as the Holdaway ratio
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What is the final measurement in the Steiner analysis?
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the inclination of the mandibular plane (Go-Gn) to SN, also referred to as the Y-axis
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What is the significance of the Y-axis in Steiner analysis?
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it is the only indicator of the vertical proportions of the face (last measurement of face)
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What is the norm for the Y axis?
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61
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