5. The long-term success of restorations depends,
to a considerable extent ??????
With the conventional impression procedures ----
--- 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
alloy.
5
6. With the lost wax modeling method, the fit of a
crown on the die can be satisfactory, but ????
Because traditional procedures are time-
consuming, efforts have been made to replace these
with computer-assisted procedures.
6
7. Milling of dental restorations from a block of
base material, such as metal, ceramic or resin, is
proposed as an alternative for fabricating
restorations ?????
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.
7
8. 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.
8
10. 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
10
11. 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.
11
14. 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.
Benefit: ?????????
14
16. 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 center
networked with satellite digitizers around the world for
the fabrication of all-ceramic frameworks.
16
20. CAD/CAM SYSTEMS
All CAD/CAM systems consist of three components:
1) A digitalization tool/scanner that transforms
geometry into digital data that can be processed by
the computer
2) Software that processes data and, depending on the
application, produces a data set for the product to be
fabricated
3) A production technology that transforms the data set
into the desired product.
20
22. CAD/CAM - PRODUCTION
CONCEPTS
Depending on the location of the components
of the CAD/CAM systems, in dentistry three
different production concepts are available:
1) chairside production
2) laboratory production
3) centralised fabrication in a production centre.
22
24. CAD/CAM components can be grouped into
three:
1) Scanner / Data collecting tool
2) Design software
3) Processing devices
24
25. 1. Scanner
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.
25
26. 1.a) Optical scanners
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
26
28. Examples of optical scanners :
Lava Scan ST (3M ESPE, white light
projections)
es1 (etkon, laser beam).
28
29. 1.b) Mechanical scanner
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
29
30. Drawbacks of the system:
The apparatus is very expensive
Long processing times compared to optical
systems.
30
32. 2. Design software
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.
32
35. 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.
35
36. 3. Processing devices
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.
36
38. 3.a) 3-axis milling devices
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
38
39. The advantages of these milling devices are short
milling times and simplified control by means of the
three axis.
Also these devices are less costly than those with a
higher number of axes.
Examples of 3-axis devises:
inLab (Sirona),
Lava (3M ESPE),
Cercon brain (DeguDent).
39
42. 3.b) 4-axis milling devices
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).
42
45. 3.c) 5-axis milling devices
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.
Trial of a Cad/Cam system for fabricating dentures-Dental materials
journal-2011 45
47. Example in the Laboratory Area: Everest
Engine (KaVo).
Example in the Production Centre: HSC
Milling Device (etkon).
47
48. MILLING VARIANTS
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.
48
51. Wet milling
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.
51
55. 3 D PRINTING
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).
55
56. It may be used for the fabrication of metal
structures either indirectly by printing in burn-
out 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.
56
57. Selective laser sintering
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
57
59. Stereolithography
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 .
59
60. 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
60
61. It may be used for the fabrication of metal
structures either indirectly by printing in burn-
out 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.
61
63. 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.
63
64. 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.
64
71. Materials
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.
71
72. The materials normally processed by
CAD/CAM systems include:
1) Metals
2) Resin materials
3) Silica based ceramics
4) Infiltrated ceramics
5) Oxide ceramics
72
73. Metals
Presently titanium, titanium alloys and chrome
cobalt alloys are processed using dental milling
devices.
The milling of precious metal alloys has been
shown to be of no economic interest, due to the high
metal attrition and the high material costs.
Examples: coron (etkon: non-precious metal alloy),
Everest Bio T-Blank (KaVo, pure titanium).
73
74. Resin material
It is possible to use resin materials directly as crown
and FPD frameworks for long-term provisional or for
full anatomical long-term temporary prostheses????
Prefabricated semi-individual polymer blanks
(semi-finished) with a dentine-enamel layer are
provided by one manufacturer (artegral imCrown,
Merz Dental).
74
75. The first commercial resin composite for
CAD/CAM –Paradigm MZ100(3M ESPE)
75
76. Silica Based Ceramics
Grindable silica based ceramic blocks are offered by
several CAD/CAM systems for the production of inlays,
onlays, veneers, partial crowns and full crowns
It is usually available as monochromatic blocks
Various manufacturers now offer blanks with
multicoloured layers [Vitablocs TriLuxe (Vita), IPS
Empress CAD Multi (IvoclarVivadent)], for the purpose
of full anatomical crowns.
76
78. Lithium disilicate ceramic blocks -full anatomical
anterior and posterior crowns,copings in the
anterior and posterior region and for three-unit
FPD frameworks in the anterior region due to
their high mechanical stability of 360 MPa
78
79. Glass Ceramics
Glass ceramics are particularly well suited to
chairside application due to their translucent
characteristics, similar to that of the natural tooth
structure.
Provides esthetically pleasing results without
veneering.
Etchable with hydrofluoric acid due to their higher
glass content – can be inserted very well using
adhesive systems.
79
81. Infiltration Ceramics
Grindable blocks of infiltration ceramics are processed
in porous, chalky condition and then infiltrated with
lanthanum glass.
All blanks for infiltration ceramics originate from the
Vita In-Ceram system (Vita) and are offered in three
variations:
Vita In-Ceram Alumina (Al2O3)
Vita In-Ceram Zirconia (70% Al2O3, 30% ZrO2)
VITA In-Ceram Spinell (MgAl2O4) 81
82. Vita In-Ceram Alumina (Al2O3): suitable for crown
copings in the anterior and posterior region, three-unit
FPD frameworks in the anterior region
Vita In-Ceram Zirconia (70% Al2O3, 30% ZrO2):
suitable for crown copings in the anterior and
posterior region, three-unit FPD frameworks in the
anterior and posterior region.
Suitable for discolored teeth due to its superior
masking ability
82
83. VITA In-Ceram Spinell (MgAl2O4):
Highest translucency of all oxide ceramics and
is thus recommended for the production of
highly aesthetic anterior crown copings, in
particular on vital abutment teeth and in the
case of young patients.
83
89. CEREC
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
89
90. 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
90
93. CEREC inLab
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.
93
94. 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 fit of the milled coping or framework on
the die and working cast.
94
95. 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
95
98. DCS Precident
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.
98
100. Procera
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.
100
101. 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.
101
103. 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.
103
106. Cercon (2002)
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.
A low-fusing, leucite-free Cercon Ceram S veneering
porcelain was used to provide the esthetic contour.
106
107. 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
107
109. Lava
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.
109
111. CEREC
The system offers two possibilities:
o Scanning for in-office fabrication
o Sending digital images to the laboratory
Transfer is only possible if the laboratory has
CEREC CONNECT
Light source: LED (blue visible light)
111
113. The occlusion is recorded by simply scanning the
arches, and digital on-screen articulating paper
shows where there are contacts.
113
114. Image acquisition is more rapid with CEREC AC
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
114
115. Lava C.O.S.
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.
115
116. 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
116
117. 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
117
131. The advantages of using CAD/CAM technology
for the fabrication of crowns and FPDs can be
summarized as:
1) application of new materials
2) reduced labor
3) cost effectiveness and
4) quality control.
131
132. High-strength ceramics that were expected to be the
new materials for FPDs frameworks have been
difficult to process using conventional dental
laboratory technologies. CAD/CAM offers a
solution for this.
CAD/CAM technology was useful and effective in
compensating for changes in dimensions that come
with processing chalky material and post-treatment
to obtain fit of crowns and FPDs to abutment teeth.
132
133. Conventional dental laboratory technologies are
traditionally labor-intensive and the labor was
vastly reduced using CAD/CAM machine.
Conventional porcelain dental laboratory
processing with powder build-up and baking
required a degree of proficiency both in terms of
reproducing natural esthetics and shaping –
increases the cost
CAD/CAM due to mass production can reduce the
cost.
133
134. Drawbacks:
Need for costly equipment
Need for extended training
Technique sensitive
Inability to image in a wet environment
134
135. The powder layer applied to the tooth surface
results in an additional thickness of 13 to 85 μm.
The restricted measuring conditions in the mouth,
including the presence of adjacent teeth, gingiva,
and saliva, make accurate recognition of the margin
of an abutment difficult
135
136. Regardless of the digitizing mode applied,
clinical parameters, such as saliva, blood, or
movements of the patient can affect the
accurate reproduction of teeth.
136
139. 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.
139
140. 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 period for the device.
140
141. To conclude,
As Duret stated, “The systems will continue
to improve in versatility, accuracy, and cost
effectiveness and will be a part of routine
dental practice in coming time”.
141
143. Text books
1. Anusavice, Shen, Rawls; Phillip’s Science of Dental
Materials 2013, 12th edition, Elsevier.
2. Ronald L Sakguchi, John M Powers; Craig’s Restorative
Dental Materials 2013, 13th edition, Elsevier.
3. Marco Anntonio Bottino; Perception: Esthetics in Metal
Free Prosthesis of Natural Teeth and Implants 2009, Artis
Medicas Dentistry.
4. Bernard Touati, Paul Miara, Dan Nathanson: Esthetic
Dentistry and Ceramic Restorations 1999, informa healthcare.
143
144. Journals
1. AD Bona, AD Noguiera, OE Pecho; Optical properties of
CAD/CAM ceramic sysems; J Dent 2014, 42: 1202-09
2. GD Quin, AA Guiseppetti, KH Hoffman; Chipping fracture
resistance of dental CAD/CAM restorative materials; Dent Mater
2014, 30(5): e112-e123
3. 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.
144
145. 4. O Moldovan, RG Luthardt, N Corcodel, H Rudolph; Three
dimensional fit of CAD/CAM made zirconia copings; Dent
Mater 2011, 27: 1273-78.
5. S Giaunetopoulos, RV Noort, E Triston; Evaluation of the
marginal integrity of ceramic copings with different marginal
angles using two different CA/CAM systems; J Dent 2010,
38: 980-86.
6. ER Batson, LF Cooper, I Duqum, G Mendonca; Clinical
outcomes of three different crown systems with CAD/CAM
technology; J Prosthet Dent 2014, 28(5): 234-40
145
146. 7. Raul Euan, OF A lvarez, JC Termes, RO Parra; Marginal adaptation
of zirconium dioxide copings: Influence of the CAD/CAM system
and the finish line design; J Prosthet Dent 2014, 112: 155-62.
8. C Chen, FZ Trindade, N de Jager, CJ Kleverlaan, AJ Feilzer; The
fracture resistance of a CAD/CAM resin nano-ceramic (RNC) and a
CAD ceramic at different thickness; Dent Mater 2014, 30: 954-62.
9. Jeramies Hey, F Beur, T Bensel, AF Boeckler; Single crowns with
CAD/CAM fabricated copings from titanium: 6 year clinical results; J
Prosthet dent 2014, 112: 150-154.
146
147. 10. AC Johnson, A Versluis, D Tantbirojn, S Ahuja; Fracture
strength of CAD/CAM composite and composite-ceramic
occlusal veneers; J Prosthodont Res 2014, 58(2): 107-114.
11. NS Birbaum, HB Aoronson; Dental impressions using 3D
digital scanners: Virtual becomes reality; Compendium 2008,
29(8): 494-505.
12. 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.
147
148. 13. PR Liu, ME Essig; A panorama of dental CAD/CAM
restorative systems; Compendium 2008, 29(8): 482-493.
14. A Begum, R Ahmed, S Islam; Digital impressions; City
Dental College J 2012, 9(2): 31-34.
15. SS Manthri, AS Bhasin; CAD/CAM in dental restorations: An
overview; Annals and Essens of Dentistry 2010, II (3): 123-28.
148
which had an impact on the later development of
dental CAD/CAM systems in the world.
4. When this system was announced, it rapidly spread the term CAD/CAM to the dental profession.
---The emergence of this system was really innovative because it allowed
SAME DAY RESTORATION
Meanwhile, a number of Japanese universities
started research and development of dental CAD/
CAM systems in the latter half of the 1980s9-13) and
several CAD/CAM systems have been available on
the domestic Japanese market.
1. The basis of this type of scanner is the
3. , with the result that all data collected by the system can also be milled
1.----With such software, crown and fixed partial dentures (FPD) frameworks can be constructed on the one hand
2. The latest construction possibilities are continuously available to the user by means of updates.
The quality of the restoration does not necessarily increase with the number of processing axes. The quality results much more from the result of the digitalisation, data processing and production process.
2. as a result of which there are no initial drying times for the ZrO2 frame prior to sintering.
3. . A higher degree of pre-sintering results in a reduction of shrinkage factor and enables less sinter distortion.
Numerically controlled machine
METALLIC AND CERAMIC FABRICATIONS WERE GENERATED IN THE SECOND GEN
Marginal fit with this system is found to be satisfactory
Initially only cam and no cad
2. Now, as a complete CAD/CAM system,
If satisfactory
The CEREC MC
XL milling center
These models can then be used for conventional laboratory
techniques or for CAD/CAM restorations
Stereolithography (SLA or SL; also known as optical fabrication, photo-solidification, solid free-form fabrication and solid imaging) is an additive manufacturing or 3D printing technology used for producing models, prototypes, patterns, and production parts up one layer at a time by curing a photo-reactive resin with a UV laser or another similar power source
1. This total processing time
was much shorter than that of conventional powder
build-up and baking of porcelain. In addition, the
operator attended the machine for only 5-6 min and
most of the process was performed automatically by
the CAD/CAM machine
1. some drawbacks of this fabrication technology have to be mentioned.
Newer materials are more esthetic and wear more like enamel and strong enough for full crown and bridges.