dental

1. CAD-CAM AND CAD-CIM IN
RESTORATIVE DENTISTRY
Presented By-
Dr. Nidhi Shrivastava
Pg Student
Dept. of Conservative Dentistry & Endodontics

2. CONTENTS
 Introduction
 History
 The CAD/ CAM process
 CAD/CAM Systems
 Restorative Materials for CAD/CAM
 Marginal Integrity of CAD/CAM Restorations
 CAD- CIM IN RESTORATIVE DENTISTRY
 Advantages/Disadvantages of CAD/CIM
 Technical innovations
 Conclusion
 References

3. INTRODUCTION
 The technological changes taking place are truly
revolutionizing the way dentistry is practiced and
the manner in which laboratories are fabricating
restorations.
 The advent of CAD/CAM has enabled the dentists
and laboratories to harness the power of computers
to design and fabricate esthetic and durable
restorations.
Sneha S.Mantri ,Abhilasha S. Bhasin. CAD/CAM in dental restorations: an overview. J. of
Annals and Essences of Dentistry 2010; 2(3): 123-128.

4.  CAD/CAM technology was introduced to the
dental community in the early 1980s. Since then
, the technology has evolved in
two directions :-
A - One is the intra-operatory application for one
appointment restoration fabrication.
B - In parallel, CAD/CAM systems for commercial
production centers and dental laboratories
emerged, expanding the range of materials that
could be used and the restoration types that could
be produced.

5.  Advances in CAD/CAM provide a new horizon for
dentistry, creating an alternative technique for
producing dental restorations. It is possible to
create dental restorations that are automatically
produced and meet the requirements for fit and
occlusion.
 The flexibility, speed, precision and efficiency of
these systems have made them useful for a wide
range of application.

6. HISTORY
 The major developments of dental CAD/CAM
systems occurred in the 1980s. Dr. Duret was the
first to develop dental CAD/CAM.
 From 1971, he began to fabricate crowns with an
optical impression of abutment followed by
designing and milling. Later he developed Sopha
system.
 Dr. Mormann (1985)developed CEREC System, an
innovative approach to fabricate same day
restorations (ceramic inlays )at the chair side in the
dental office.

7. Prof Werner Mörmann (left)and Dr Marco Brandestini in
1985 with the CEREC 1 prototype. (zurich
university,switzerland)

8.  Dr.Anderson (1994)developed Procera System .
He attempted to fabricate titanium copings by
spark erosion and introduced CAD/CAM technology
into the process of composite veneered
restorations(1996) .
 This system later developed ( 1998 onwards) as a
processing center networked with satellite digitizers
around the world for the fabrication of all ceramic
frameworks .

9.  During the last 2 decades, exciting new
developments have led to the success of
contemporary dental CAD/CAM technology.
 Several methods have been used to collect 3-
dimensional data of the prepared tooth using optical
cameras, contact digitization, and laser scanning.
 Replacement of conventional milling discs with a
variety of diamond burs has resulted in major
improvements in milling technology.
 Another vital factor has been the development of
alumina (aluminum oxide) and zirconia (zirconium
oxide) ceramic materials, which possess excellent
machinability and physical strength

10. THE CAD/ CAM PROCESS
 A CAD/CAM system utilizes a process chain
consisting of scanning, designing and milling
phases.
 The scanning device converts the shape of the
prepared teeth into three dimensional (3-D) units of
information (voxels). The computer translates this
information into a 3-D map (point cloud). The
operator designs a restoration shape using the
computer which generates a tool path, which is
used by the milling device to create the shape from
a restorative material.

12. CAD/CAM SYSTEMS
 Based on their production methods these systems
can be divided into the following groups.
In office system : Most widely and commercially
used in Cerec System. This system can scan the
tooth preparation intraorally and by selecting
appropriate materials, the dentist can fabricate the
restorations and seat it within a single appointment.
Anuvanice KJ (Ed) Phillips RW. Phillips Science of Dental Materials. 11th Edition

13. CAD/CAMS – Dental laboratory models: The
indirect systems scan a stone cast or die of the
prepared tooth, in the dental lab (eg Cerec-in lab).
Many of this system produce copings which require
the dental technician to add esthetic porcelain for
individualization and characterization of the
restoration.

14. CAD/CAM for outsourcing dental lab work using
networks: since the design and fabrication of the
framework for high strength ceramics is technique
sensitive, new technologies using CAD/CAM with
network machining center that is outsourcing the
framework fabrication using an internet have been
introduced.

15. COMMON CAD/CAM SYSTEMS
Cerec : An acronym for chair side economic
reconstruction of esthetic ceramic
Cerec introduced in 1980s, improved cerec 2 introduced
in 1996 and the advanced 3-D Cerec 3 in 2000. With
Cerec 1 and Cerec 2, an optical scanner is used to scan
the prepared tooth or impression and a 3-D image is
generated on monitor. A milling unit is used to prepare
the restoration.
With newer Cerec 3-D, the operator records multiple
images within seconds, enabling clinician to prepare
multiple teeth in same quadrant and create a virtual cast
for the entire quadrant.

16. Designed restoration is transmitted
to a remote milling unit for
fabrication.
Cerec in-lab is a lab system in
which dies are laser scanned and
image displayed on screen.
After designing VITA In-cream
blocks are used for milling. The
coping is glass infiltrated and
veneer porcelain added .
In vitro evaluation of marginal
adaptation of crown of cerec 3-D
(47.5 µm+-19.5 µm) was better
compared with cerec 2 (97.0 +-
33.8 µm).(Ellingsen et al,2002)
(left) Simulated digitized image,
(right) partially milled feldspathic
ceramic (VITABLOCS Triluxe
Forte) processed by the Sirona
inLab CAD-CAM system.
(Left) CAD-CAM ceramic block
before milling. (Center)
An intermediate stage of milling.
(Right) After removal of the inlay
from the mounting stub.

18. DCS Precident:
Comprises of a Preciscan laser
Scanner and Precimill CAM multitool milling center.
The DCS software automatically suggests, connector
sizes and pontic forms for bridges. It can scan 14 dies
simultaneously and mill up to 30 frameworks unit in
one fully automated operation. It is one of the few
systems that can mill titanium and fully dense sintered
zirconia.
An in vitro study showed that marginal
discrepancies of alumina and ziroconia based
posterior fixed partial denture machined by the DCS
system was between 60 µm to 70µm.(tinschert et al 2001)

20. Cercon:
commonly referred to as a CAM system, it does not
have a CAD component. The system scans the wax
pattern and mills a zirconia bridge coping from
presintered zirconia blanks, which is sintered at
1350 C for 6-8 hrs.
Veneering is done with a low fusing, leucite free
cercon Ceram to provide esthetic contour.
Marginal adaptation for cercon all ceramic crowns
and fixed partial dentures was reported 31.3 µm
and 29.3 µm respectively (Ariko et al 2003)

22. Procera All Ceram System –
Introduced in 1994, it is the first system which
provided outsourced fabrication using a network
connection. Once the master die is scanned the
3-D images is transferred through an internet link to
processing center where an enlarged die is milled
by a computer controlled milling machines.

24. This enlargement compensates for sintering
shrinkage.
Aluminum oxide powder is compacted on the die
and coping is milled before sintering at a very high
temp (>1550°C). The coping is sent back to the lab
for porcelain veneering.
According to research data average marginal gap
for Procera all Ceram restoration ranges from 54
µm to 64 µm.( May et al 1998)

25. CICERO system (computer integrated crown
Reconstruction) –
Introduced by Denison et al in 1999, it includes
optical scanning, metal and Ceramic sintering and
computer assisted milling to obtain restoration.
Basic reconstruction includes layered life like
ceramic for natural esthetics, a precision milled
occlusal surface and a machined high strength
ceramic core.

26. The aim of CICERO is to mass produce ceramic
restoration at one integrated site. It includes rapid
custom fabrication of high strength alumina coping
and semi finished crowns to be delivered to dental
laboratories for porcelain layering / finishing.

27. Lava CAD/CAM System –
Introduced in 2002, used for fabrication of zirconia
framework for all ceramic restorations. This system
uses yttria stabilized tetragonal zirconia poly
crystals (Y-TZP) which have greater fracture
resistance than conventional ceramics. Lava
system uses a laser optical system to digitize
information.
The Lava CAD software automatically finds the
margin and suggests a pontic.
CAM produces an enlarged framework to
compensate shrinkage.

28. A partially sintered ziroconia block is selected for
milling. Milled framework undergoes sintering to
attain final dimensions, density and strength.
Studies on marginal adaptation of Y-TZP bridges
processed with Lava system for 2 milling times
(75 mins Vs 56 mins) did not affect the marginal
adaptation (61+-25 µm Vs 59+-21 µm ).
(Hertlein et al 2003)

29. The combination of materials that can be used and
restoration types that can be produced vary with
different systems. Some CAD/CAM systems can
fabricate a final restoration with some materials with
acceptable strength and esthetics while others
require subsequent veneering to achieve acceptable
esthetics

32. RESTORATIVE MATERIALS FOR CAD/CAM
CAD/CAM systems based on machining of
presintered alumina or zirconia blocks in
combination with specially designed veneer
ceramics satisfy the demand for all-ceramic
posterior crowns ,inlays and onlays . Many ceramic
materials are available for use as CAD/CAM
restorations.
Common ceramic materials used in earlier dental
CAD/CAM restorations have been machinable
glass ceramics such as Dicor-k or Vita Mark II.

33. Although mono-chromatic, these ceramic materials
offer excellent esthetics, biocompatibility, great
color stability, low thermal conductivity, and
excellent wear resistance.
They have been successfully used as inlays, onlays
,veneers , and crowns.
However, Dicor and Vita Mark II are not strong
enough to sustain occlusal loading when used for
posterior crowns.
For this reason, alumina and zirconia materials are
now being widely used as dental restorative
materials.

34. These ceramic agents may not be cost- effective
without the aid of CAD/CAM technology.
In-Ceram l, first described by Degrange and
Sadoun, has been shown to have good flexural
strength and good clinical performance.
However, the manufacture of conventional
In-Ceram restoration takes up to 14 hours.
By milling copings from presintered alumina or
zirconia blocks within a 20 minute period and
reducing the glass infiltration time from 4 hours
to 40 minutes, CEREC in Lab decreases fabrication
time by 90%.

35. Zirconia is strong and has high biocompatibility.
Fully sintered zirconia materials can be difficult to
mill, taking 3 hours for a single unit. Compared with
fully sintered zirconia, milling restorations from
presintered or partially sintered solid blocks is
easier and less time-consuming, creates less tool
loading and wear, and provides higher precision.
After milling, In-Ceram spinell, alumina, and
zirconia blocks are glass infiltrated to fill fine
porosities. Other machinable presintered ceramic
materials are sintered to full density, eliminating the
need for extensive use of diamond tools.

36. Under stress the stable tetragonal phase may be
transformed to the monoclinic phase with a 3% to
4% volume increase. This dimensional change
creates compressive stresses that inhibit crack
propagation.
This phenomenon, called “transformation
toughening,” actively opposes cracking and gives
zirconia its reputation as the “smart ceramic.” The
quality of transformation toughness and its affect on
other properties is unknown.

37. Zirconia copings are laminated with low fusing
porcelain to provide esthetics and to reduce wear of
the opposing dentition. If the abutment lacks
adequate reduction the restoration may look
opaque.
Because they normally are not etchable or
bondable, abutments require good retention and
resistance form. Alumina and zirconia restorations
may be cemented with either conventional methods
or adhesive bonding techniques. Conventional
conditioning required by leucite ceramics (eg,
hydrofluoric acid etch) is not needed.

38. Microetching with Al2O3 particles on cementation
surfaces removes contamination and promotes
retention for pure aluminum oxide ceramic.
A resin composite containing an adhesive
phosphate monomer in combination with a silane
coupling/bonding agent can achieve superior long-
term shear bond strength to the intaglio surface of
Procera AllCeram and Procera AllZirkon
restorations.

39. CAD/CAM systems also can be applied to
restorations requiring metal and are used to
fabricate implant abutments and implant-retained
overdenture bars.
The DCS system can fabricate crown copings from
titanium alloy with excellent precision .

41. MARGINAL INTEGRITY OF CAD/CAM
RESTORATIONS
One of the most important criteria in evaluating
fixed restorations is marginal integrity.
Evaluating inlay restorations, Leinfelder and
colleagues (1993) reported that marginal
discrepancies larger than 100 µm resulted in
extensive loss of the luting agent.
O’Neal and colleagues (1993)reported the
possibility of wear resulting from contact of food
particles with cement when gap dimension
exceeded 100 µm.

42. Essig and colleagues (1999) conducted a 5-year
evaluation of margin gap wear and reported that
vertical wear is half of the horizontal gap. The wear
of the gap increased dramatically in the first year,
becoming stable after the second year.
McLean and Von Fraunhofer (1971)proposed that
an acceptable marginal discrepancy for full
coverage restorations should be less than 120 µm.

43. Christensen (1966) suggested a clinical goal of 25
µm to 40 µm for the marginal adaptation of
cemented restorations. However, most clinicians
agree that the marginal gap should be no greater
than 50 µm to 100 µm. Current research data
indicate that most dental CAD/CAM systems are
now able to produce restorations with acceptable
marginal adaptation of less than 100 µm.
Perng-Ru Liu. A Panorama of Dental CAD/CAM Restorative Systems. J. of Compendium
2005; 26(7):507-512.

44. CAD- CIM IN RESTORATIVE DENTISTRY
 The problem of aesthetic restorations of hard dental
tissues has long been present in dental medicine,
not only in the replacement of dental tissue
destroyed by caries but also in the treatment of
traumatic injuries, endogenic and exogenic
discoloration, hypoplastic defects of hard dental
tissue, disorders in the contour and size of teeth
and other malformations.
 For this purpose, apart from the classical composite
restorations, onlays and inlays, laboratory produced
composites and ceramic inlays and veneers are
also used.

45.  CAD/CAM (Computer Aided Design / Computer
Aided Manufacture) system first appeared in dental
medicine in 1989 with the device CEREC (CEramic
REConstruction) for the fabrication of inlays, onlays
and labial veneers during one appointment in the
dental surgery.
 An optical “impression” is used instead of the
classical impression procedure, and the dentist’s
own evaluation of the contour and size of the inlay,
onlay or veneer.
 The development of the technological method
enabled complete integration of all phases of
fabrication, and this is offered by the CAD/CIM
system (Computer Aided Design / Computer
Integrated Manufacturing).

46. ADVANTAGES OF CAD/CIM-
The advantages of the method are its
simplicity: the laboratory is not required,
there is no classical impression procedure (the
method can be repeated as necessary),
rapid fabrication (it is possible to fabricate several
veneers during one appointment), acceptable cost
(no laboratory costs, time saving), and the
fabricated restoration is of the same or higher
quality than the laboratory fabricated restoration.

47. DISADVANTAGE-
High costs of the CEREC apparatus and mastering
the technique.

48.  Ceramic inlays, onlays, and veneers have
increasingly become part of the clinical routine in
dental offices. The adhesive technique permits
preparations that preserve the dental hard tissues
and widens the range of ceramic restorations.
 The key features of dental ceramics are
excellent biocompatibility,
good machinability,
high abrasion resistance, and
durable color stability, as well as enamel-like
modulus of elasticity and thermal conductivity.

49.  To date computer-aided design-computer-
integrated manufacturing (CAD-CIM) restorations
have shown more than 6 years of good clinical
performance and have thus gained scientific
acceptance.
 For computer-generated inlays, practically pore-free
industrial ceramics that do not require glazing are
used, and the inlays offer excellent marginal seals
at both the enamel and dentinal interfaces when
cemented with resin cements.

50.  The Cerec unit (Siemens) is based on the process
developed by Mormann and Brandestini' and is the
result of constant development yia different
generations of Cerec units

52. TECHNICAL INNOVATIONS
The Cerec 2 camera: Optical impression
The Cerec 2 camera has been given a new design
and is easy to handle.
To maintain good accessibility to the oral cavity, the
size of the intraoral frontal part of the camera has
not been modified. An important hygienic feature is
the detachable cover, which can be sterilized by dry
heat in case of exposure to a higher risk of
infection.

53. Usually, the cover is removed, a plug is inserted in
its opening, and it is then washed in a thermal
disinfector. The camera can also be wiped clean
with a dispensable cloth moistened with a liquid
disinfectant.

54. The further development of the intraoral three
dimensional camera has been carried out in
accordance with the original Cerec process.
Pixel size(picture element) has been reduced from
54x54um to 25 X 29 um.
Thus, in the pixel image system, the voxel (volume
element) pattern has come to 25 X 25 X 29 um in
the pixel image system. Because of the
optimization of the optical beam path by means of
symmetric beam geometry, major measurement
errors in the measuring volume of a typical inlay
have been brought down to less than +- 25 um.

56. A more accurate control of the projected measuring
pattern and the particularly low-noise level
processing of the video signal has resulted in a
distinct reduction of the spurious components in the
measuring data.
Because of the smaller pixel size and the higher
accuracy in the depth measuring, the resolution of
the optical impression has been doubled compared
to that of the Cerec 1 unit.

57. IMAGE PROCESSING
Data representation of a typical mesio-occlusodistal
inlay in the image memory has been increased from 4
million voxel in Cerec 1 to 32 million voxel in Cerec 2.
Accordingly, the amount of data to be processed has
grown by the factor 8, As a result of the six times
more efficient computing capacity, the surface
operations can be carried out in about the same time
and the line operations are about three times faster.
Main memory (ID 4) overloads no longer occur.

59. USER INTERFACE
On the 14 x 17-cm color monitor, the preparation is
represented at xl2 magnification. Thus,
compared to the x8 magnification in Cerec 1, the
accurate drawing of the construction lines has been
facilitated. Proven elements, such as selecting the
tooth to be treated by clicking at it in the tooth arch,
confirmation of the procedure steps by clicking at the
icons, and alternative options in the interactive
windows, have been maintained,
extended, and at the same time simplified by
Automation .Accordingly, camera calibration
and the adjust procedure of the depth profile
data are now fully automated.

60. In conjunction with the automatic adjust, the
measuring range has been extended to the complete
range of depth of field of 10 mm. Thus, even very
deep cavities no longer present clinical limitations of
any kind.
Another useful element is the automatic proposition of
the proximal contact lines. Although, for the time
being, these still have to be aligned to the approximal
surfaces of the adjacent teeth by editing to establish
the desired close contacts, input errors in defining the
starting and end points of the proximal contact lines
have been eliminated.

61. User elements
The monitor can be swiveled and tilted, thus
facilitating visual control of the video image in the
search mode during the taking of the optical
impression.
Furthermore, this arrangement allows the patient to
watch the design and the program procedure. During
the taking of the optical impression, the camera is
activated by a newly arranged foot switch. Unlike the
usual operational technique, the foot switch is
activated not by pressing but by lifting the foot.
This setup has hygienic and engineering advantages,
for which reason this solution has
been chosen.
Operators soon get accustomed to it.

62. Extrapolation occlusion-Simultaneous grinding –
Three different programs for design are available:
Extrapolation, Correlation, and Veneer. There are
three choices in designing the occlusion;
(/) anatomically adapted (Extrapolation),
(2) Correlated to a functionally generated path
(Correlation),and
(3) Buccolingually flat(linear)

63. for practical use, the interactive design technique, in
conjunction with the extrapolation program for
inlays and onlays, is the method of choice.
An essential point of this method is the tracing
of the mesiodistal main fissure line.

65. Fissure depth is determined in inlays by the height of
the adjacent cavosurface margin line, and in onlays
also by the marginal ridge-cusp line.
For every supporting point of the fissure line, the next
point on the cavosurface margin line or on the
marginal ridge-cusp line, respectively, is searched for
in buccolingual direction. To ensure sufficient
porcelain thickness of at least 1.0 mm, a sufficient
preparation depth in the fissure section has to be
secured.

66. Through triangulation of the occlusal surface,
triangles are calculated, each being defined by its
edge points and two inclination vectors per triangle
side." The triangle surfaces are interpolated and
form a continuous surface.
Grinding is performed by a cylindrical diamond
(diameter of 2mm, particle size of 64 pm, 77,000 rpm,
and cutting speed of about 8 m/s), working
simultaneously with the radial infeed grinding
of the grinding disk (64 um particle size, 18,000 rpm,
and cutting speed of about 38 m/s)

69. CEREC ONLAYS: EXTENDED MACHINING
With the extended machining option of the Cerec 2
system, complex floor shapes in inlays and onlays
can be ground with the cylindrical diamonds. Cuspal
coverage, circular margins, and buccal
margins with different levels are possible.
Occlusal floor sections with differing levels can also
be designed; the grinding disk-dependent orientation
of pulpo-axial box walls no longer
exists. However, to be feasible, the preparation
shapes have to be located within the 2-mm resolution
range of the cylindrical diamonds. Generally, this
does not present any limitations in practical use.

70. Domagoj Glavina Ilija SkrinjariÊ . A New Method for Fabricating Ceramic Inlays: the CAD/CIM System
Technology for the 21stCentury. Acta Stomatol Croat 2001;35(1):53-58.

71. An anatomically adapted occlusion is created and, with
little additional work, can be morphologically finished
with a 40 um contouring diamond and an 8um finishing
diamond and polished with flexible disks.

74. VENEERS: INCISAL EDGE COVERAGE
The Cerec system is the only method in dentistry to
permit the direct machining of ceramic yeneers.
In the United States, where the standards of esthetic
requirements are high, more than 20% of Cerec users
regularly produce veneers in one appointment and
place them directly with an adhesive technique. With
the Cerec 1 unit and the extended computer software.
Veneer 1.0, veneers and onlays can easily be designed
and manufactured. Cerec 2 software, COS 4,20, permits
custom veneer preparations with any
kind of anatomic reduction, as well as the easy design
of the veneer and its direct manufacturing.

75. Class IV situations combined with incisai edge
coverage maybe designed directly, without using a
wax template for the optical impression.With the
extended machining option, any three-dimensional
shape can be manufactured directly.

76. GRINDING PRECISION AND ACCURACY OF FIT
Grinding precision, the final element in the CAD/CIM
manufacturing process, is crucial
to an accurate fit. The result to be achieved should be
influenced as little as possible by the state of
abrasion of the grinding tools, by the type of material
used, and the amount of material to be removed. The
optimized calibration process compensates for wear
of the tools. The reduction of the bearing tolerances
and the reinforcement
of the axes have increased the rigidity of the Cerec 2
grinding unit as a whole and of the grinding drive
in particular.

77. These modifications also reduced the deformations
occurring during the service life of a grinding disk as a
result of increasing contact pressure.

78. The Windows-based CEREC 3 system was introduced
in 2000. While these first three models were based on
2D technology, 3D software introduced in 2003 allowed
dentists to construct restorations based on virtual three-
dimensional models using the computer. While for some
time it was only possible to attach all-ceramic crowns
adhesively, the increased precision of the new
generation of milling machine, MC XL, which was
launched in 2007, made it possible to attach crowns
using dental cement. In 2009, Sirona switched to a new
imaging technology, the CEREC Bluecam, which is
based on short-wave blue light, thus significantly
increasing the level of precision in comparison to the
previous 3D camera. Since 2010, the use of Biogeneric
has made it possible to individually reconstruct the
occlusal surfaces of damaged or missing teeth, while
achieving a natural look.

80. The latest development is the CEREC Omnicam
intraoral camera, which was launched on the market
in 2012 and facilitates powder-free digital
impressions in natural colors.

82. CONCLUSION
CAD/CAM systems offer automation of fabrication
procedures with standardized quality in a shorter
period of time. They have the potential to minimize
inaccuracies in technique and reduce hazards of
infectious cross contamination. It allows application of
newer high strength materials with outstanding
biocompatibility combined with adequate mechanical
strength, provisions for esthetic designs, excellent
precision of fit and longetivity.
However, these advantages must be balanced
against the high initial cost of CAD/CAM systems
and the need for additional training.

83. Patient’s expectations, financial constrain, operator’s
preference, as well as availability of CAD/CAM
systems will dictate the suitability of this type of
restorations on an individual basis in the future.
Innovations will continue to affect
and challenge dentistry.

84. REFERENCES
 Mormann W.H. The origin of the cerec method: a
personal review of the first 5 years. Int J Comput
Dent. 2004; 7(1): 11-24.
 Ellingsen LA, Fasbinder DJ. An in vitro evaluation
CAD/CAM ceramic crowns. J. Dent Res 2002;
81:331.
 Sneha S.Mantri ,Abhilasha S. Bhasin. CAD/CAM in
dental restorations: an overview. J. of Annals and
Essences of Dentistry 2010; 2(3): 123-128.
 Anuvanice KJ (Ed) Phillips RW. Phillips Science of
Dental Materials. 11th Edition, WB Saunders
Company, Pennsylvania, USA, Chapter 21, pg 692.

85.  Domagoj Glavina Ilija SkrinjariÊ . A New Method for
Fabricating Ceramic Inlays: the CAD/CIM System
Technology for the 21stCentury. Acta Stomatol Croat
2001;35(1):53-58.
 Perng-Ru Liu. A Panorama of Dental CAD/CAM
Restorative Systems. J. of Compendium 2005;
26(7):507-512.
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Edelhoff . CAD/CAM in Dentistry: New Materials
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 Mormann W.H. ,The evolution of the cerec
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