L5 Intra and Extraoral Scan Flashcards
digitalization
the conversion of text, pixtures, or sound into a digital form that can be processed by a computer
digitalization
the conversion of text, pictures, or sound into a digital form that can be processed by a computer
digital dental impression
the conversion of 3D image data of oral and other structures into a digital format that can be processed by a computer
STL (meaning)
steriolithography
STL (definition)
STL stands for
steriolithography
STL (definition)
standard tesselation language or standard
STL stands for
steriolithography
standard tesselation language
STL files
-accepted by most CAD/CAm software
-no information on colors
-no information on internal structures
image capture made by
light projection and capture
reconstruction of 3D data
matching poitns of interest taken uner different angles
what type of light is captured by the scanner
diffuse light
d
diffuse reflection
the reflection of light from a surface such that incident ray is reflected at many angles, rather than at just one angle
what is detected to reconstruct 3D data?
detection of transition areas, such as strong curvatures, physical limits, or difference of gray intensity
what is created to evaluate similarity between images?
transformation matrix
resolution (definition)
number of points per mm squared
does resolution affect the accuracy of scan?
no
what affects the accuracy of scan?
software advancement
depth of view
distance between scanner tip and object needed to capture an image
is it better to have a fixed or range depth of view?
better to have RANGE
speed of scanner
faster = more convenient
are smaller or larger scanners good for capturing hard areas?
smaller
closed system scanners
-sends scan to one of a few software programs for designing or milling
main advantage of closed system scanner
straightforward flow
main disadvantage of closed system scanner
limited
example of closed system scanner
PrimeScan (CEREC)
open system scanner
sends scans to all other open system software programs for design for milling
main advantage of open system scanner
versatile
main disadvantage of opens ystem scanner
complex workflow
main disadvantage of opens system scanner
complex workflow
examples of closed system scanners
Trios 4 (3Shape)
emerald (planmeca)
caries detection by scanner
same / not better than visual detection
potential against histological detection!
shade matching by scanner
not there yet!
digital intraoral scanner may not be used as an accurate method of shade selection (must confirm with visual verification)
2 factors that can affect your scan
isolation
retraction and placement of margin
isolation and scanner
saliva or blood in the scan will appear as hard tissue
scanning in a dry field is a must!
retraction and placement of margin and scanner
you must be able to clearly visualize your margin so that the scanner can capture it
the scanner does not see what you can’t see!
scanning errors
- contaminated field / unexposed margins
- missing data
- double scan
extraoral scanning
-light capture
-reconstruction of 3D data (matching of points of interest taken under different angles)
what is different about extraoral scanning
-capture area
-moisture control (not an issue)
-double scan (not a problem)
is there a difference in accuracy of extraoral vs intraoral scanning?
no
benefits of intraoral scanning
-saves time
-supra or equigingival margins
-hard and attached soft tissue
-severe undercuts
benefits of extraoral scanning
-saves cost
-subgingival margins
-boarder molding (complete denture)
