1. DIGITAL IMPRESSIONS IN
PROSTHODONTICS
PRESENTED BY: NAVREET KAUR BAJWA
UNDER GUIDANCE OF: DR. KAVIPAL SINGH

2. CONTENT
 INTRODUCTION
 BACK-GROUND OF CURRENT IMPRESSION MATERIALS
 DISADVANTAGES OF CURRENT IMPRESSION TECHNIQUES
 EVOLUTION OF DIGITAL IMPRESSIONS
 PRE-REQUISITEOF DIGITAL IMAGING
 DIGITAL IMPRESSION TECHNIQUES
 HOW IT ISDONE?
 PROCESSING STEPS IN THEDENTAL PRACTICE:COMPARISON
 BENEFITS OF DIGITAL IMPRESSIONS
 DISADVANTAGES
 CONCLUSION

3. INTRODUCTION
 Today,digitaltechnologycontrolsalmostevery aspectofourlife, anddentistryis noexceptiontoit.
 Millions ofimpressions aretakenevery yearforthe productionofcrowns,bridges, andpartialdentures.
 Making impressionswith elastomericimpression materialis aneverydayprocedurein almostevery general
dentalpractice.
 A new wayto dispensetraysandimpression materialsis nowavailablethatcreatedigital impressionsofa
patient’steeth.
 The digitalimpression conceptis emerging rapidlyonthe horizonanditis believed thatdigital impressions
willsolvethe challenges anddifficultiesoftheconventionalimpressions.

4. Back-ground of Current Impression
Materials
 The historyoftoday’straditionalimpressionmaterialsbegan in
the mid-1930’swiththe introductionof reversible hydrocolloids.
 This wasthefirstmaterialthatmade theimpression ofundercuts
possible.
 Bythe1955,polysulphideswereintroducedandforthe firsttime
anelastomericimpressionmaterialwasused.
 Therewasagreat improvementin reproducingthe
characteristicsofpreparedteeth,butstill therewereinherent
problemslike shrinkageofmaterial.

5.  In 1966, further improvements in impression materials occurredwith
the introduction of polyether. This material proved tobefar superior to
the hydrocolloid followed by silicones in 1976.
 Though they are hydrophobic by nature buteven in the presence of a
moist environment, they are highly dimensional stable resulting in a
superior elastic recovery.
 With the advancement of time and technology improvements are made
to these materials to reduce tearing, chair time and enhance the patient
comfort.

6. DISADVANTAGES OF CURRENT
IMPRESSION TECHNIQUES
 Errors in tray selection.
 Limitations inthe impression material’s flow and hydrophilicity.
 Short workingtime.
 Patient movement .
 Tearingand deformation of the impression duringremoval.
 Dimensional stability of the set impression.
 Required disinfection.
 Inadequate wetting and voids when pouringthe cast.
 Messy materials.
 Tedious and time taking.
 Tongueand saliva.
 Discomfort to patient.

7. Evolution of Digital Impressions
 Dr.Duretfirstintroducedthe CAD/CAMconcepttodentistryin 1973in Lyon,Francein his thesis
entitledEmpreinteOptique,whichtranslatestoOpticalImpression.
 The conceptofCAD/CAM systemswasfurtherdeveloped byDr.Mormann,aSwiss Dentist,andMr.
Brandestini,whowas anelectricalengineer.
 Thefirstcommerciallyavailabledigitalimpression systemforusein thefield ofdentistrywas
introducedin 1980pioneered byPROCERAandCEREC.
 Over thelast10years,systemslike 3M LavaC.O.S., CadentiTero, E4DDentist,and3ShapeTrioshave
been introduced.
 Todate,variousCAD/CAM systemsare nowavailablefordentalapplications.Eachemploysaspecific,
distincttechnique formaking impressions.

8. Intraoral
scannersare
usedto create a
digital imageof
the patient’s
teeth
Theneed for
traditional
impression
materials
eliminated.
Using either a
laser orvideo,
animageis
acquired witha
digital
scanning
device.
Patient’s
dentition and
bite
relationship
optically
recorded.
Lightis
projected from
the tipof the
scanner,anda
cameracollects
data,
Manipulation
done to
produce a
digital model of
the patient’s
dentition

9. PRE-REQUISITE OF DIGITAL IMAGING
 Digital camera.

10. Software to create image using CAD/CAM
system. &
Connection to export the image

11. Milling unit to fabricate the prosthesis (in
house or in lab).

12. DIGITAL IMPRESSION TECHNIQUES
 In-Office CAD/CAM Impression Techniques
 CEREC (Sirona)
 E4D Technologies
 Chairside Digital Impression Techniques
 iTero
 CEREC
 Lava C.O.S.systems.

13. CEREC
In-office
fabrication
Sendingthe
digitalimages
directly tothe
laboratory.
CEREC AC gives dentists
the choice of
implementing

14. Thescanner operates using visible blue light
emanating from light emitting diodes (LEDs)
with shorter wavelengths of light than
previous CEREC models, increasing the
accuracy ofthe scan.
LIGHT USED

15. IMAGE
ACQUISITION
Image acquisition is more rapid with
CEREC AC than with previous models
due to the continuous capturing of a
series of images by the scanner oncein
position.

16. Theocclusion is recordedby simply scanning
the arches, and digital on-screenarticulating
papershows where there arecontacts. Images
of interdigitation of the opposing teeth also
show if there is sufficient interocclusal
clearancefor
the prosthesis.
RECORDING OCCLUSION

17. MILLING
After the clinician has verified the
digital preparation the CEREC MC XL
milling center can beused to createfull
contour crowns in six minutes.
Alternatively, the MC L Compact
Milling Unit can beused.

18. E4D
TECHNOLOGIES
TheE4D can beused for all fixed prosthesis except
bridges and implants.
TheE4D has separate scanning and milling units within a
cart, with automated interunit communication.

19. TheE4D (D4D TECHNOLOGIES) takes
several images using a red light laser to
reflect off of the tooth structure, oscillating
at 20,000 cycles per second to capture the
series of images and createa 3-D model.
LIGHT USED

20. IMAGE
ACQUISITION
Thescanner is held at a specific
distance above the tooth, aided by
rubber stops on the scannerhead, and
the area is centered forimaging (aided
by a bull’s-eye on-screenguide).

21. Theocclusion and occlusal height ofmilled
restorations areassessed from the
preparation’s arch and an image of a
physical registration bitehence there is no
requirement toscan the opposing arch.
RECORDING OCCLUSION

22. MILLING
Themilling component includes a
touch-screenpanel that provides
guidance during the process. The
digital scan is transferred to the milling
machine(with wireless orwired
transmission), and the restoration is
milled from both sides simultaneously.

23. iTero
TheiTero chairside digital impression scanner utilizes parallel confocal imaging
to capture a 3D digital impression of the tooth surface, contours and gingival
structure.
Thescanner has the ability to capture preparations for crowns, bridges.

24. LIGHT USED
TheParallel confocal imaging uses laser and
optical scanning to digitally capture thesurface
and contours of the tooth and gum structure. The
Cadent iTero scannercaptures 100,000 points of
red laser light and has perfect focus images of
more than 300 focal depths of the tooth structure.
All of these focal depthimages arespaced
approximately 50 μmapart. This system does not
require the use of powder.

25. IMAGE
ACQUISITION
During scanning, a series of visual and verbal
prompts are giventhat are customized for the
patient beingtreated and guide the clinician
through the scanning process. Foreach
preparation, a facial, lingual, mesio-proximal and
disto-proximal viewis recordedin around 15 to
20 seconds, after which the adjacentteeth are
scanned from the facial and lingual aspect.

26. RECORDING OCCLUSION
Theocclusion is captured by taking two interocclusal
views with the patient in centric, after which the
dentist can viewthe image within 30 seconds and
ascertain that the interocclusal clearance is sufficient
for the planned prosthesis prior to the patient leaving.
No bite registration material is required.

27. MILLING
Themilling of the models is done on a
5-axis milling machine,using a
proprietary resin material.
Simultaneously, the dental laboratory
technician can export the digital
impression file to his orher CAD/CAM
system and begin fabrication of
copings and/or prosthesis.

28. Lava C.O.S. systems
TheLava C.O.S.system is used for chairside digital impression making.

29. LIGHT USED
TheLava C.O.S.scanner contains 192 LEDs and 22 lens
systems with a pulsating blue light and uses continuous
video to capture the data that appears onthe computer
touch screenduring scanning. Almost 2,400 data sets
are captured per arch.

30. IMAGE
ACQUISITION
After scanning the tooth preparation,
the dentist is able to rotate and
magnify the view on the screenand
can also switch from the 3-D image to
a 2-D view. The full arch is scanned
after the preparation imaging is
complete, followed by the opposing
quadrant.

31. RECORDING OCCLUSION
Theocclusion is assessed by scanning from the buccal
aspect with the teeth in occlusion and viewing the
arches digitally.
Theimages aretransmitted directly to laboratory where
the laboratory technician digitally marks the margins
and sections the virtual model priortosending this
digitally to the manufacturer.

32. MILLING
Themodel is virtually
ditched, articulated and sentto the
model fabrication center
for stereolithography (SLA) to create
acrylic models.

33. Differentiation between various camera
available
CEREC E4D iTero LAVACOS
Full-archdigital impressionsindicated YES NO YES YES
PowderingRequired YES NO NO Some
AcquisitionTechnology Blue light LED Redlight LASER Confocal Bluelight LED
video
In-OfficeMilling YES YES NO NO
ConnectivitytoLabs YES NO YES YES
RestorationDesign (CAD) Software YES YES NO NO
Indicationforbridges YES NO YES YES

34. HOW IT IS DONE?

35. A dentist holds a scanning wand which is connectedto a digital camera

36. This uses blue wavelength light to record images of the teeth to make a 3D computer model.

37. A 3D model created by the scanning wand is displayed on a computer screen.

38. Blocks of dental ceramic material that will be used to createdental restorations.

39. A milling machinelocated inside the dental office carves a restoration from a block of
ceramicmaterial.

40. A computermodel showing howthe final restorations will look is sent tothe milling machine
for fabrication.

41. Thefinal prosthesis, placed the same day.

43. Processing steps in the dental practice
Conventional impressions
Prepare the impression tray
Make silicone impression
Transfer impression
Disinfect
Complete orderform
Dental laboratory steps
Clean
Trim impression
Pour stone material
Trim arch
Pin
Trim base
Perform saw-cut
Ditching
Fabrication of prosthesis
Finished model
Apply Optispray
Acquire digital impression
Complete order form
Data transfer Connect portal
Dental laboratory steps
Confirm receipt of data
Check accuracy ofdata in 3D
Finished model
Digital Impressions

44. BENEFITS OF DIGITAL
IMPRESSION
 Accuracy of impressions
 Opportunity to view, adjust and rescan impressions
 No physical impression for patient
 Savestime and one visit for in-office systems
 Opportunity to viewocclusion
 Accurate restorations created on digital models
 Potential for cost-sharing of machines

45.  Accurate, wear- and chip-resistant physical CAD/CAM derived models
 No layering/baking errors
 No casting/soldering errors
 Cross-infection control
 Patient is comfortable

46. DISADVANTAGES OF DIGITAL
IMPRESSIONS
 Digital equipment is very expensive.
 Digital equipment’s are complex and trained operator is
required to operate and maintain the device.
 Good and up-to- date laboratory support is required.
 Those with small mouths may have difficulty with this
procedure.

47. CONCLUSION
With the numerous advantages of
digital impressions over traditional
impressions and the ability to
benefit from digital impression
taking and/or CAD/CAM, more and
more dentists are purchasing digital
impression systems. It will likely be
a routine procedure in most dental
offices in the near future, as
dentists, laboratory technicians, and
patients all reap the benefits.

48. REFERENCES
 iData Research Inc., 2007, U.S. Market for Dental Prosthetic
Devices.
 Beuer F, Schweiger J, Edelhoff D. Digital dentistry: an
overview of recent developments for CAD/CAM generated
restorations. Br Dent J. 2008;204(9):505-11.
 Nathan S. Birnbaum; Heidi B. Aaronson;Chris Stevens; Bob
Cohen. 3D Digital Scanners: A High-Tech Approach to More
Accurate Dental Impressions; Inside Dentistry; April 2009; 5,
(4).
 Puri S. Maximizing and simplifying CAD/CAM dentistry;
www.ineedce.com

49.  Svend Carlsen. Witnessing the evolution of digital impression solutions; Dental
Tribune U.S. Edition | May 2012
 Sabiha S. Bunek, DDS; Chris Brown, BSEE. The Evolving Impressions of Digital
Dentistry ; Inside Dentistry; January 2014
 Sankalp Sharma,1 Swatantra Agarwal,2 Divya Sharma,3 Sanjeev Kumar,4
Nishtha Glodha. IMPRESSION; DIGITAL VS CONVENTIONAL: A REVIEW ;
Annals of Dental Specialty Vol. 2; Issue 1. Jan – Mar 2014