detailed description of CAD-CAM in prosthodontics

1. CAD-CAM
PRESENTED BY – DR. ANIKET SHINDE
I ST YEAR PG STUDENT
DEPARTMENT OF PROSTHODONTICS

2. CONTENTS
• Introduction
• History
• Components of CAD/CAM
• Subtractive and Additive techniques
• Materials for CAD/CAM
• Common CAD/CAM systems
• Recent advances
• Summary
• References

3. INTRODUCTION
• With the conventional impression procedures and procedures
like lost-wax-casting technique in the production of metal
castings or frameworks, their accuracy is greatly influenced by
the properties of the impression materials, investment and
casting
• Also traditional procedures are time consuming, efforts have
been made to replace these techniques with computer-assisted
procedures.

4. • To produce milled restorations with accurate fit, digitization of
the prepared tooth surface and converting the data into control
signals for computer-assisted milling is used.
• Computer-aided design/computer-aided manufacturing
(CAD/CAM) technology which was developed in the late 1980s
for dentistry, incorporates the above mentioned techniques and
it significantly reduced and/or eliminated problems associated
with dental castings.

5. HISTORY
• In dentistry, the major developments of dental CAD/CAM
systems occurred in the 1980s.
• Dr. Duret – developer of Sopha System
• Dr. Moermann - the developer of the CEREC system
• Dr. Andersson - the developer of the Procera system

6. • Dr. Duret fabricated crowns (1971) with the functional shape of
the occlusal surface using a series of systems that started with
an optical impression of the abutment tooth in the mouth,
followed by designing an optimal crown considering functional
movement, and milling a crown using a numerically controlled
milling machine.

7. • Dr. Moermann, the developer of the CEREC system.
• He directly measured the prepared cavity with an intra-oral
camera, which was followed by the design and carving of an
inlay from a ceramic block using a compact machine set at
chair-side.

8. • Dr.Andersson, the developer of the Procera system
• Fabricated titanium copings by spark erosion and introduced
CAD/CAM technology into the process of composite veneered
restorations.
• Later developed as a system with processing centre networked
with satellite digitizers around the world for the fabrication of
all-ceramic frameworks.

9. • CAD/CAM components can be grouped into
• That transforms geometry into digital data
that can be processed by the computer
1) Scanner / Data
collecting tool
• That processes data and, depending on the
application, produces a data set for the
product to be fabricated
2) Design
software
• That transforms the data set into the desired
product.
3) Processing
devices

11. 1.
• It includes the data collection tools that measure three
dimensional jaw and tooth structures and transform them into
digital data sets.
• Basically there are two different scanning possibilities:
• 1) optical scanners
• 2) mechanical scanners.

12. •
• It involves the collection of 3D structures in a so-called
‘triangulation procedure’.
• The source of light and the receptor unit are in a definite angle
in their relationship to one another.
• White light projections or a laser beam can serve as a source of
illumination
• Examples of optical scanners :
• Lava Scan ST (3M ESPE, white light projections)
• es1 (etkon, laser beam).

14. • The master cast is read mechanically line-by-line by means of
a ruby ball and the three-dimensional structure measured.
• The Procera Scanner from Nobel Biocare
• This type of scanner is distinguished by a high scanning
accuracy, whereby the diameter of the ruby ball is set to the
smallest grinder in the milling system

15. • With such softwares, crown and fixed partial dentures (FPD)
frameworks can be constructed.
• Some systems also offer the opportunity to design full
anatomical crowns, partial crowns, inlays, inlay retained FPDs,
and telescopic primary crowns.
• The software available on the market is being continuously
improved.

17. • The data of the construction can be stored in various data
formats.
• The basis therefore is often standard transformation language
(STL) data.
• Many manufacturers, however, use their own data formats,
specific to that particular manufacturer.

18. • The construction data produced with the CAD software are
converted into milling strips for the CAM-processing and finally
loaded into the milling device.
• Processing devices are distinguished by means of the number of
milling axes:
• 3-axis devices
• 4-axis devices
• 5-axis devices.

20. • This type of milling device has degrees of movement in the three
spatial directions, and so the mill path points are uniquely defined by
the X -,Y-, and Z – values
• A milling of subsections, axis divergences and convergences,
however, is not possible
• This demands a virtual blocking in such areas
• The advantages of these milling devices are short milling times and
simplified control by means of the three axis and they less costly
• Examples of 3-axis devises:
• inLab (Sirona),
• Lava (3M ESPE),
• Cercon brain (DeguDent).

21. • In addition to the three spatial axes, the tension bridge for the
component can also be turned infinitely variably .
• As a result it is possible to adjust bridge constructions with a
large vertical height displacement into the usual mould
dimensions and thus save material and milling time.
• Example: Zeno (Wieland-Imes).

22. • In addition to the three spatial dimensions and the rotatable tension
bridge (4th axis), the 5-axis milling device has the possibility of
rotating the milling spindle (5th axis)
• This enables the milling of complex geometries with complex shapes
such as denture base resins.
• Example in the Laboratory Area: Everest Engine
• Example in the Production Centre: HSC Milling Device

23. • Dry processing :
• Applied mainly with respect to zirconium oxide blanks with a
low degree of pre-sintering.
• Advavtages:
• Minimal investment costs for the milling device
• No moisture absorption by the die ZrO2 mould
• Disadvantages:
• Higher shrinkage values for the frameworks.
• EXAMPLES : [Zeno 4030 (Wieland- Imes), Lava Form and Cercon
brain].

24. • In this process the milling diamond or carbide cutter is
protected by a spray of cool liquid against overheating of the
milled material.
• Useful for all metals and glass ceramic material in order to
avoid damage through heat development.
• ‘Wet’processing is recommended, if zirconium oxide ceramic
with a higher degree of pre-sintering is employed for the
milling process.
• Examples:
• Everest (KaVo), Zeno 8060 (Wieland-Imes),
• inLab (Sirona).

25. • It is another manufacturing approach to build objects, one layer
at a time and adding multiple layers to form an object.
• It is also known as additive manufacturing or rapid prototyping
(RP).
• It may be used for the fabrication of metal structures either
indirectly by printing in burnout resins or waxes for a lost-wax
process, or directly in metals or metal alloys like FPD and
removable partial denture (RPD), polymerized prostheses, and
silicon prosthesis.

26. • A scanning laser fuses a fine material powder, to build up
structures layer by layer, as a powder bed drops down
incrementally, and a new fine layer of material is evenly spread
over the surface.
• Resolution as high as 60 μm may be obtained, and the
structures printed are supported by the surrounding powder

27. • Light-sensitive polymer cured layer by layer by a scanning laser
in a vat of liquid polymer.
• It is a widely employed RP technology. It was invented by
Charles Hull .
• It is an additive manufacturing process in which a liquid
photocurable resin acrylate material is used.
• Stereolithography uses a highly focused Ultraviolet (UV) laser to
trace out successive cross-sections of a 3D object in a vat of
liquid photosensitive polymer
• It may be used for the fabrication of metal structures either
indirectly by printing in burnout resins or waxes for a lost-wax
process, or directly in metals or metal alloys like FPD and
removable partial denture (RPD), polymerized prostheses, and

29. • Currently, subtractive milling is the most widely implemented
computer-aided manufacturing protocol in dentistry and it has
been shown to be a suitable method for fabricating intraoral
prostheses.
• Additive methods have the advantage of producing large
objects, with surface irregularities, undercuts, voids, and
hollow morphology that makes them suitable for
manufacturing facial prostheses and metal removable partial
denture frameworks

32. • Materials for processing by CAD/CAM devices depends on the respective
production system
• Some milling devices are specifically designed for the production ZrO2 frames,
while others cover the complete palette of materials from resins to glass
ceramics and high performance ceramics.
The materials normally processed by
CAD/CAM systems include:
1) Metals
2) Resin materials
3) Silica based ceramics
4) Infiltrated ceramics
5) Oxide ceramics

33. • CAD/CAM systems may be categorized as:
• In-office system
• Laboratory based system
• Milling center system

34. • IN OFFICE SYSTEMS :
• Sirona, with their CEREC line of products, is the only manufacturer
that currently provides both in-office and laboratory-based systems.
• CEREC 1 and CEREC 2 – optical scan of the prepared tooth with a
charged-coupled device (CCD) camera, and the system automatically
generates a 3D digital image on the monitor
• Then, the restoration is designed and milled
• With the newer CEREC 3D, the operator can record multiple images
within seconds.
• This enables the clinicians to prepare multiple teeth in the same
quadrant and create a virtual cast for the entire quadrant.
• On the virtual model, the operator designs the contour of the
restoration and electronically transmits the data to a remote milling
unit for fabrication.
• Better marginal adaptation

36. • LABORATORY BASED SYSTEMS :
• It is a laboratory-based system
• Working dies are laser-scanned and a digital image of the
virtual model is displayed on a computer screen.
• After designing the coping or framework, the laboratory
technician inserts the appropriate ceramic block into the CEREC
inLab machine for milling.
• A wide range of high strength ceramic blocks are available for
the inLab system
• It includes Vita In-Ceram blocs two sintered ceramics: inCoris
ZI (zirconium oxide) and inCoris AL (aluminium oxide) (Sirona
Dental Systems, LLC).
• After milling, the technician manually inspects and verifies the

37. • Subsequently, the coping will be adjusted to maximize
adaptation to the die.
• The coping or framework then is either glass-in filtrated (Vita
In-Ceram) or sintered (zirconium oxide or aluminium oxide),
and the veneering porcelain is added

38. MILLING CENTRE SYSTEMS
• The system is comprised of a Preciscan laser scanner and
Precimill CAM multitool milling center.
• It can scan 14 dies simultaneously and mill up to 30 framework
units in a single, fully automated operation.
• It can mill titanium as well as fully dense sintered zirconia.

39. • Procera/AllCeram was introduced in 1994
• Uses an innovative concept for generating alumina and zirconia
copings.
• The master die is scanned and the data is send to the
processing center.
• After processing,the coping is send back to the lab for
porcelain veneering.
• The recommended preparation marginal design for a
Procera/AllCeram restoration is a deep chamfer or shoulder
with a rounded internal line angle and a well-defined
cavosurface finish line.
• The recommended coping thickness is 0.4 mm to 0.6 mm.

41. Nobel Biocare USA LLC has introduced various implant
abutments for its Procera system— titanium (1998) alumina
(2002) zirconia (2003)
• Capable of generating alumina (two to four units) and zirconia
(up to 14 units) bridge copings.
• The occlusal-cervical height of the abutment should be at least
3 mm, and the pontic space should be less than 11 mm.

42. NEWER CONCEPTS
• Wax pattern (coping) with a minimum thickness of 0.4 mm are
to be made which is scanned and the Cercon Brain milling unit
milled a zirconia coping from proprietary presintered zirconia
blanks.
• The coping then was sintered in the Cercon Heat furnace (1350
C) for 6 to 8 hrs.
• Allow-fusing, leucite-free Cercon Ceram S veneering porcelain
was used to provide the esthetic contour.

43. • In 2005, DENTSPLY Ceramco introduced the Cercon Eye 3D
laser optical scanner and Cercon Art CAD design software.
• Now, as a complete CAD/CAM system, Cercon can produce
single units and bridges up to nine units from pre-sintered
zirconia milling blocks that are offered in white and ivory
shades without any infiltration required

44. • Lava system Introduced in 2002.
• It includes a mobile cart, a touch screen display and a scanner
with camera at the end.
• Camera has LEDs and lens systems
• Data-send through wireless to the laboratory where the die is
cut and margins are marked digitally.

45. • The system offers two possibilities:
• Scanning for in-office fabrication
• Sending digital images to the laboratory
• Transfer is only possible if the laboratory has CEREC CONNECT
• Light source: LED (blue visible light)
• The occlusion is recorded by simply scanning the arches, and
digital on-screen articulating paper shows where there are
contacts.

46. • Image acquisition is more rapid with CERECAC
• The clinician can verify the preparation and interocclusal
clearance
• The system will also digitally mark the margins and provide a
digital version of the proposed restoration prior to its
fabrication

47. • The Lava C.O.S. system is used for chairside digital impression
making
• Scanner contains 192 LEDs and 22 lens systems with a
pulsating blue light
• It uses continuous video to capture the data that appears on
the computer touch screen during scanning
• 2,400 data sets are captured per arch.
• Can rotate and magnify the view on the screen
• Full arch is scanned after the preparation imaging is complete,
followed by the opposing quadrant, and the occlusion is
assessed
• Images can be transmitted directly to an authorized laboratory

48. • Laboratory technician digitally marks the margins and sections
the virtual model prior to sending this digitally to the
manufacturer
• The model is then virtually ditched, articulated and sent to the
model fabrication center for stereolithography (SLA) to create
acrylic models

49. CASE REPORT

56. SUMMARY
• Newer CAD/CAM systems demonstrate increasing user friendliness,
expanded capabilities, improved quality, and greater range in
complexity and application.
• Chairside digital impressions systems allow for the creation of
accurate and precise laboratory models and restorations involving
less chairside time.
• Fractures of ceramic FPDs tended to occur in the connector areas
because of the concentrated stress. Therefore, the design of the
connector, particularly the dimensions, must be made independently
depending on the type of ceramic material used for the framework.
• CAD better guarantees the durability and reduces the risk of fracture.
• Processing data can be saved and followed up during the functional

57. REFERENCES
• Anusavice, Shen, Rawls; Phillip’s Science of Dental Materials
2013, 12th edition, Elsevier.
• NS Birbaum, HB Aoronson; Dental impressions using 3D
• digital scanners: Virtual becomes reality; Compendium 2008,
29(8): 494-505.
• T Miyasaki, Y Hotta, J Kuni et al; a REVIEW OF DENTAL
• cad/cam: Current status and future perspectives from 20 years
of experience; Dent Mater 2009, 28(1): 44-56.

58. • AD Bona, AD Noguiera, OE Pecho; Optical properties of
CAD/CAM ceramic sysems; J Dent 2014, 42: 1202-09
• GD Quin, AA Guiseppetti, KH Hoffman; Chipping fracture
resistance of dental CAD/CAM restorative materials; Dent Mater
2014, 30(5): e112-e123
• Z Zhang, Y Tamaki, Y Hotta, T Miyasaki; Novel method for
titanium crown casting using a combination of wax patterns
fabricated by a CAD/CAM system and a non expanded
investment; Dent Mater 2006, 22: 681-87.