Content uploaded by Gülay Uzun
Author content
All content in this area was uploaded by Gülay Uzun on Feb 25, 2018
Content may be subject to copyright.
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=tbeq20
Biotechnology & Biotechnological Equipment
ISSN: 1310-2818 (Print) 1314-3530 (Online) Journal homepage: http://www.tandfonline.com/loi/tbeq20
An Overview of Dental CAD/CAM Systems
G. Uzun
To cite this article: G. Uzun (2008) An Overview of Dental CAD/CAM Systems, Biotechnology &
Biotechnological Equipment, 22:1, 530-535, DOI: 10.1080/13102818.2008.10817506
To link to this article: https://doi.org/10.1080/13102818.2008.10817506
© 2008 Taylor and Francis Group, LLC
Published online: 15 Apr 2014.
Submit your article to this journal
Article views: 1009
View related articles
Citing articles: 8 View citing articles
530 BIOTECHNOL. & BIOTECHNOL. EQ. 22/2008/1
REVIEW MB
MEDICAL BIOTECHNOLOGY
Keywords: CAD/CAM, scanning software, dental materials,
future trends
Introduction
Computer-aided design (CAD) and computer-aided
manufacturing (CAM) technology systems use computers to
collect information, design, and manufacture a wide range
of products. With CAD/CAM, parts and components can
be designed and machined with precision using a computer
with integrated software linked to a milling device. This
technology was introduced to dental community in the early
1980s. The earliest attempt to apply CAD/CAM technology to
dentistry began in the 1970s with Bruce Altschuler, Francois
Duret, Werner Mormann, and Marco Brandestini. Young
and Altschuler (51) fi rst introduced the idea of using optical
instrumentation to develop an intraoral grid surface mapping
system in 1977. The fi rst commercially available dental
CAD/CAM system was CEREC, developed by Mormann and
Brandestini (25).
A dental restoration must fi t its abutment within a 50 μm
range (12). This requirement calls for the system to have a very
accurate data collection technique, suffi cient computing power
to process and design complex restorations, and a very precise
milling system.
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.
The hope and expectation was that automation could
achieve the following:
- to produce higher- and more uniform-quality material by
using commercially formed blocks of material;
- to standardize restoration-shaping processes;
- to reduce production costs.
The use of high-strength structural materials like alumina-
and zirconia-based ceramics for restoration cores and
frameworks, which can be shaped only by CAD/CAM systems,
has both increased the lifetime of restorations and expanded
the demand for CAD/CAM-produced restorations (16). As a
result, the number of CAD/CAM systems currently available
to the dental community has increased substantially within the
last few years (14, 39, 49).
All CAD/CAM systems have three functional components:
data capture or scanning to capture and record data about
the oral environment (tooth preparation, adjacent teeth and
occluding tooth geometry); CAD to design the restoration to
fi t the preparation and to perform according to conventional
dental requirements; and CAM to fabricate the restoration.
Data Capture
Data capture differs remarkably between commercially
available dental CAD/CAM systems (49). An intraoral digital
3-D scanning device (digitizer) is an integral component of the
CEREC system (CEREC 3D, Sirona Dental Systems GmbH,
Bensheim, Germany). The Evolution 4D system, currently
under development by D4D Technologies (Richardson, Texas),
also is expected to have intraoral data capture capabilities.
Other commercially available CAD/CAM systems capture
data from models, using mechanical or optical digitizers of
various types. With few exceptions, these high-precision
digitizers use technologies that prevent them from being used
intraorally. Mechanical digitizers, for instance, must map the
entire surface of a prepared tooth while accurately maintaining
the relative position of the device to the tooth. Many optical
digitizers are exceptionally sensitive to any motion. Slight
movement of a patient during data acquisition with either of
these types of scanner would compromise the quality of the
data, ultimately leading to a restoration that would not fi t. In
most cases, the scanner used to capture data is an integral part
of the CAD/CAM system and operates only in combination
with dedicated CAD software.
AN OVERVIEW OF DENTAL CAD/CAM SYSTEMS
G. Uzun
Hacettepe University, School of Dental Technology, Sıhhıye, Ankara, Turkey
Correspondence to: Gülay Uzun
E-mail: vuzun@hacettepe.edu.tr
ABSTRACT
For 20 years, exciting new developments in dental materials and computer technology have led to the success of contemporary
dental computer-aided design /computer-aided manufacturing (CAD/CAM) technology.
This article provides an overview of the status of current CAD/CAM systems, describes components of CAD/CAM technologies
and suggests future possibilities.
531
BIOTECHNOL. & BIOTECHNOL. EQ. 22/2008/1
Restoration Design
Several CAD software programs are available commercially
for designing virtual 3-D dental restorations on a computer
screen. Some of these programs can design restorations nearly
matching the excellence of restorations produced by master
dental technicians. The degree of interaction needed from the
CAD/CAM system operator to design a restoration varies,
ranging from substantial to no required user operations. Even
in the most automated systems, the user generally has the
option to modify the automatically designed restoration to fi t
his or her preferences. Like the data acquisition systems, the
software programs usually are proprietary to the CAD/CAM
system and can not be interchanged among systems. When
the design of the restoration is complete, the CAD software
transforms the virtual model into a specifi c set of commands.
These, in turn, drive the CAM unit, which fabricates the
designed restoration.
Restoration Fabrication
CAM uses computer-generated paths to shape a part. A diverse
set of technologies has been used to create dental restorations.
Early systems relied almost exclusively on cutting the
restoration from a prefabricated block with the use of burs,
diamonds or diamond disks (44). This approach, in which
material is removed to create the desired shape, is termed a
“subtractive method”; material is subtracted from a block to
leave the desired shaped part (the restoration) (13). Subtractive
fabrication can create complete shapes effectively, but at the
expense of material being wasted. Approximately 90 percent
of a prefabricated block is removed to create a typical dental
restoration. As an alternative, “additive” CAM approaches like
those used in rapid prototyping (also called “solid free-form
fabrication”) technologies are beginning to be used in dental
CAD/CAM systems (26). Selective laser sintering is one of
the technologies that can be used to fabricate either ceramic or
metal restorations (Medifacturing, Bego Medical AG, Bremen,
Germany; Hint ELs, Hint-ELs, Griesheim, Germany). In this
method, the computer design of the part (the dental restoration)
generates a path much like a cutting tool path in existing CAD/
CAM systems. However, instead of cutting, the system sinters
material along the path, building a part from a “bath” of ceramic
or metal powder and adding material continually until the
complex part is complete. No excess material remains. Some
commercially available CAD/CAM systems use a combination
of additive and subtractive CAM approaches. In one (Procera,
Nobel Biocare, Göteburg, Sweden), an enlarged metal die fi rst
is milled based on the 3-D data for the prepared tooth with
the use of the subtractive approach. (This enlargement takes
into account shrinkage associated with sintering the fi nal
restoration to achieve its fi nal strength.) Powder is compacted
under pressure onto the metal die, creating an oversized block
by means of an additive approach; the block then is milled away
to create the outer contours of the restoration. The oversized
restoration is removed from the die and sintered to make the
material as dense as possible and to shrink it to its correct
size. Another combined CAM approach (Wol-Ceram, Wol-
Dent, Ludwigshafen, Germany) involves the path, building
a part from a “bath” of ceramic or metal powder and adding
material continually until the complex part is complete. No
excess material remains. Another combined CAM approach
(Wol-Ceram, Wol-Dent, Ludwigshafen, Germany) involves
the application of a slurry of alumina powder directly to
a master die using an additive electrophoretic dispersion
method, which creates a coping. The operator trims away by
hand excess material extending beyond the margin. The outer
contour of the restoration is shaped using a subtractive CAM
approach. The operator then removes the coping from the die
and infi ltrates glass. An additive approach also has been used
to generate copings and frameworks for bridges from pure
alumina oxide and zirconia-based ceramics with superfi ne
nanodispered ceramic particles smaller than 100 nanometers
(ce.inovation, Inocermic, Hermsdorf, Germany). This system
is housed in a production center, and details of the fabrication
have not been disclosed. Brick and colleagues (6) reported that
it produces frameworks with high strength. A different additive
rapid prototyping technique, 3-D printing, is being used to
design and then print a wax pattern of a restoration (WaxPro
printer of the Pro 50 system, Cynovad, Saint- Laurent, Quebec,
Canada) (45). Operating like an inkjet printer, the machine
builds wax patterns of frameworks and full crowns. The wax
pattern subsequently is cast or pressed in the same manner as
manually waxed restorations would be. An advanced printing
unit (Cynovad) prints a resin-type material instead of the wax.
This system has an expanded capability beyond that of most
CAD/CAM systems for dental restorations; it also can be used
to fabricate auricular prostheses (37).
Integration of these technologies has resulted in the
introduction of several highly sophisticated CAD/CAM
systems: CEREC3 and in lab DCS Precident; Procera; Lava;
Cercon Smart C e r a m i c s ; Everest; Denzir; DentaCad;
and Evolution D4D. CAD/CAM technology provides several
advantages from the dental laboratory perspective. CAD/
CAM systems offer automation of fabrication procedures with
increased quality in a shorter period of time. Dental CAD/
CAM systems have the potential to minimize inaccuracies in
technique and reduce hazards of infectious cross-contamination
associated with conventional multistage fabrication of indirect
restorations. However, capital costs of these CAD/CAM
systems are quite high and rapid large-scale production of good
quality restorations is necessary to achieve fi nancial viability.
CAD/CAM systems have been created for dental
applications other than producing restorations. One system
(SL, Perfactory, Envisiontec GmbH, Gladbeck, Germany)
uses stereolithography, another additive process to produce
3-D dental components from acrylics (48). Three-dimensional
occlusal splints and similar components are created by
selectively light-curing sequential layers of acrylic monomer in
a liquid. In addition, CAD/CAM systems have been developed
to fabricate surgical templates (custom drill guides) to guide
dental implant placement (31) (SurgiGuide, Materialise,
Leuven, Belgium) and working models, permiting restorations
532 BIOTECHNOL. & BIOTECHNOL. EQ. 22/2008/1
to be inserted immediately after implants have been placed (41)
(Nobel Guide software, Nobel Biocare). Both systems use data
captured from computerized tomographic scans in conjunction
with CAD software to determine the most ideal restoration
placement, and CAM Technologies generate the templates and
working models.
Restorative Materials for CAD/CAM
Using CAD/CAM systems, operators can fabricate restorations
from an array of materials. These include ceramics, metal alloys
and various composites. The ceramics currently being used
for restorations are predominantly alumina- (including those
subsequently infi ltrated with glass), zirconia- and porcelain-
based ceramics. The combination of materials that can be used
and restoration types that can be produced by different systems
vary.
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 and fi xed partial dentures. Many ceramic
materials are available for use as CAD/CAM restorations (Table
1). Common ceramic materials used in earlier dental CAD/
CAM restorations have been machinable glass ceramics such
as Dicor (Dentsply Caulk, Milford, DE 19963) or Vita Mark
II (Vident, Bera, CA 92821). Although monochromatic, these
ceramic materials offer excellent esthetics, biocompatibility,
great color stability, low thermal conductivity, and excellent
wear resistance (24). They have been successfully used as
inlays (28, 33), onlays (28), veneers (21), and crowns (3).
However, Dicor and Vita Mark II are not strong enough to
sustain occlusal loading when used for posterior crowns (19).
For this reason, alumina and zirconia materials are now being
widely used as dental restorative materials. These ceramic
agents may not be cost-effective without the aid of CAD/CAM
technology. For instance, In-Ceram l, fi rst described by Sadoun
and Degrange (30), has been shown to have good fl exural
strength and good clinical performance (29, 32). However, the
manufacture of conventional In-Ceram restoration takes up to
14 hours (15). By milling copings from presintered alumina
or zirconia blocks within a 20 minute period and reducing the
glass infi ltration time from 4 hours to 40 minutes, Cerec inLab
decreases fabrication time by 90%. Zirconia is strong and has
high biocompatibility. Fully sintered zirconia materials can be
diffi cult 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 infi ltrated to fi ll fi ne porosities. Other
machinable presintered ceramic materials are sintered to full
density, eliminating the need for extensive use of diamond tools.
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.
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,
hydrofl uoric acid etch) is not needed. Microetching with Al2O3
particles on cementation surfaces removes contamination and
promotes retention for pure aluminum oxide ceramic (1). Two
in vitro studies recommended that 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 (4, 5).
TABLE 1
Common Restorative Materials for Dental CAD/CAM Systems
Restorative material CAD/CAM system Indications Cementation
Dicor MCG Cerec Inlay, onlay veneer Adhesive (dual-cured)
Vita Mark II Cerec Inlay, onlay veneer, anterior crown Adhesive (dual-cured)
Pro CAD Cerec Inlay, onlay veneer, anterior crown Adhesive (dual-cured)
In-Ceram Spinell Cerec 3D, Cerec inLab Anterior crown Adhesive (self-cured),
conventional
In-Ceram Alumina Cerec 3D, Cerec inLab, DCS
Precident Crown and anterior bridge Adhesive (self-cured),
conventional
In-Ceram Zirconia Cerec 3D Cerec inLab, DCS
Precident Crown and bridge Adhesive (self-cured),
conventional
Alumina Procera Crown and bridge Adhesive (self-cured),
conventional
Partially sintered Zir-
conia
DCS Precident, Lava, Procera,
Everest, Cercon Crown and bridge Adhesive (self-cured),
conventional
Fully sintered Zirconia DCS Precident, Everest Crown and bridge Adhesive (self-cured),
conventional
533
BIOTECHNOL. & BIOTECHNOL. EQ. 22/2008/1
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 (2).
Several articles have reported the extension of CAD/CAM
technology to the fabrication of maxillofacial prostheses such
as the artifi cial ear (7, 18, 40, 42).
Review of Common CAD/CAM Systems
CAD/CAM systems may be categorized as either in-offi ce or
laboratory systems. Among all dental CAD/CAM systems,
Cerec is the only manufacturer that provides both in-offi ce and
laboratory modalities. Similar to Cerec is the Evolution D4D.
Laboratory CAD/CAM systems have increased signifi cantly
during the last 10 years and include DCS Precident, Procera,
Cerec inLab, and Lava. Cercon is a laboratory system that
possesses only CAM capabilities without the design stage.
Business Models For Producing CAD/CAM Restorations
As might be expected, based on the number of CAD/CAM
systems available and the broad range in size and cost, different
business models for producing CAD/CAM restorations have
emerged. These include in-offi ce systems, dental laboratory
systems, dental laboratories working in collaboration with a
production center, and a network or open-concept business
model.
In-offi ce system model. The fi rst, and so far only,
commercially available in-offi ce system is the Cerec system
(Sirona). With this system, all three steps involved in the
automated production of restorations can be accomplished
in a dental offi ce. The dentist can prepare a tooth and, by
selecting appropriate materials, can fabricate a restoration and
seat it within a single appointment. The supplement to this
issue of JADA summarizes the evolution of this system and
the performance of restorations produced by it as it reaches its
20th anniversary.
Dental laboratory. The dental laboratory model is similar
to that used in producing conventional restorations. The dental
offi ce sends an impression or model of the prepared and
opposing teeth to the laboratory, and the laboratory fabricates
the restoration. The only difference with this CAD/CAM
technology is that at least part of the fabrication is automated.
Unfortunately, the cost of many of these CAD/CAM systems is
high, often precluding all but a few of the largest laboratories
from offering this service.
Dental laboratory–production center model. In the dental
laboratory–production center model, the dental laboratory
has the data acquisition and design software available to
it (36). The laboratory technician scans models and designs
the restorations, making optimal use of his or her skills. The
laboratory sends the fi nished design to a production center,
where it is converted into appropriate commands to drive
the CAM component of a CAD/CAM system. This model
minimizes the cost to the laboratory and has the potential to
improve fabrication effi ciencies.
Network or open-concept model. The network or open-
concept model is similar to the dental laboratory–production
center model, but in this model multiple commercial
laboratories and/or production centers collaborate. The dental
laboratories have data acquisition and design capabilities
and the production center and/or other dental laboratories
have the CAM capabilities. In general, only limited types
of materials can be fabricated with any one CAM system.
With this network model, greater fl exibility with regard to
material choices is possible; the same restoration design can be
produced from a broader array of materials. In the most open
concept, a standard fi le format (similar to that used in solid
free-form fabrication) facilitates transfer of design data to any
number of different CAM systems, permitting interesting and
more fl exible material choices and pricing strategies. Only a
few manufacturers of digitizers and software programs offer
networking or openconcept possibilities. Most dental CAD/
CAM systems operate as closed-data systems. That is, all
components are linked by a unique data format, precluding
data from one system from being used to shape a restoration
with a different system (46, 47). The notable exceptions are
the ZENO Tec (Wieland Dental+Technik GmbH, Pforzheim,
Germany) and Hint ELs (Hint-ELs) systems.
CAD/CAM Systems of the Future
No automated system currently offers the fl exibility with
regard to restoration types and material choices that is possible
with traditional fabrication methods. However, new and
emerging technologies will continue to push the boundaries
we face today. An emphasis on intraoral data acquisition
scanners and digitizers is likely. This could lead ultimately
to the elimination of impressions and stone models. It is
likely that future digitizers or scanners will be more robust,
facilitating accurate data capture despite the differences in
foundation restorations within teeth, as well as differences in
saliva and soft tissue. This means that data pertaining to the
prepared, adjacent and opposing teeth could be sent directly to
a CAD/CAM system without being interpreted by a technician
or clinician. CAD software is relatively mature and probably
will not change dramatically. However, likely enhancements
may include a simpler user interface and integration of virtual
articulators, which would facilitate automatic design of the
occlusal surface.
The CAM component of dental CAD/CAM systems likely
will undergo the most remarkable changes. A major challenge
that has not been addressed completely in existing systems is the
completely automated, economical, high-precision production
of restorations. Highspeed machining is being adapted,
permitting faster removal of material. This reduces machining
time and could reduce production costs. Femtosecond lasers
have been introduced for cutting dental materials, including
zirconiabased ceramics (43). Direct shell production uses a
rapid prototyping process similar to selective laser sintering
534 BIOTECHNOL. & BIOTECHNOL. EQ. 22/2008/1
to create ceramic investments in the shape needed, without a
wax pattern (50).
Other systems may shape parts using additive techniques
such as selective laser sintering, stereolithography and 3-
D printing, as described above. Another rapid prototyping
approach that has shown much promise is direct-write
assembly (34). With this system, the material from which
the part is made is incorporated into special inks. The ink is
delivered through specialized nozzles along the “tool path,”
defi ning the designed restoration to create the complex 3-D
part. As the ink leaves the nozzle, it freezes instantaneously
into the desired shape; however, for high-strength parts such as
ceramic dental restorations, the materials need to be made more
dense. This technology could expand the breadth of material
choices, eliminate damage induced during subtractive shaping
operations and minimize the amount of material needed to
produce a restoration.
One limitation of current CAD/CAM systems is their
inability to incorporate esthetic veneers with strong (but
relatively unesthetic) cores and frameworks. Lasers have been
shown to sinter translucent veneering silicate ceramics after
they have been applied to a core using a plotter system and
direct shell production casting (50). Other approaches such as
direct-write assembly also may be able to improve esthetics by
applying an esthetic outer layer onto a strong core layer within
a single additive CAM process. Many new technologies are
being applied in industrial fi elds, resulting in the creation of
complex 3-D parts from an array of materials. In the future,
practical application of these technologies to dentistry may
provide unexpected paradigm shifts in fabrication approaches
and materials options.
As more scanning and fabrication technologies are
introduced to fabricate restorations, it is likely that more
cooperative networks and open systems will be used (47).
People with special expertise may be required to select and
combine the components of open CAD/CAM systems.
Informed decisions will be needed to optimize the choice of
materials, hardware for shaping the materials and specifi c
dental indications.
Marginal Integrity of CAD/CAM Restorations
One of the most important criteria in evaluating fi xed
restorations is marginal integrity. Evaluating inlay restorations,
Leinfelder and colleagues reported that marginal discrepancies
larger than 100 μm resulted in extensive loss of the luting
agent (20). O’Neal and colleagues (27) reported the possibility
of wear resulting from contact of food particles with cement
when gap dimension exceeded 100 μm. Essig and colleagues
(11) conducted a 5-year evaluation of gap wear and reported
that vertical wear is half of the horizontal gap. The wear of
the gap increased dramatically in the fi rst year, becoming
stable after the second year. McLean and Von Fraunhofer (23)
proposed that an acceptable marginal discrepancy for full
coverage restorations should be less than 120 μm. Christensen
(9) 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 (8, 17, 35). 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 (10, 22, 38).
Conclusions
CAD/CAM systems have enhanced dentistry by providing
high-quality restorations. The evolution of current systems and
the introduction of new systems demonstrate increasing user
friendliness, expanded capabilities, and improved quality, and
range in complexity and application. New materials also are
more esthetic, wear more nearly like enamel, and are strong
enough for full crowns and bridges. Existing CAD/CAM
systems vary dramatically in their capabilities, each bringing
distinct advantages, as well as limitations. None can yet acquire
data directly in the mouth and produce the full spectrum of
restoration types (with the breadth of material choices) that can
be created with traditional techniques. Emerging technologies
may expand the capabilities of future systems, but they also
may require a different type of training to use them to their full
capacity.
REFERENCES
1. Awliya W., Oden A., Yaman P., Dennison J.B., Razzoog
M.E. (1998) Acta Odontol. Scand., 56, 9-13.
2. Besimo C., Jeger C., Guggenheim R. (1997) Int. J.
Prosthodont., 10, 541-546.
3. Bindl A., Mormann W.H. (2004) Eur. J. Oral Sci., 112,
197-204.
4. Blatz M.B., Sadan A., Blatz U. (2003) Quintessence Int.,
34, 542-547.
5. Blatz M.B., Sadan A., Martin J., Lang B. (2004) J.
Prosthet. Dent., 91, 356-362.
6. Brick E.M., Rudolph H., Arnold J., Luthardt R.G.
(2004) Comput. Med. Imaging. Graph., 28(3), 159-65.
7. Carpentieri J.R. (2004) Pract. Procedures Aesthet. Dent.,
16, 755-757.
8. Chaffee N., Lund P.S., Aquilino S.A., Diaz-Arnold A.M.
(1991) Int. J. Prosthodont., 4, 508-516.
9. Christensen G.J. (1966) J. Prosthet. Dent., 16, 297-305.
10. Ellingsen L.A, Fasbinder D.J. (2002) J. Dent. Res., 81,
331.
11. Essig M., Isenberg B.P., Leinfelder K., Liu P.R. (1997)
[abstract 1201] J Dent Res, 76, 164.
12. Estafan D., Dussetschleger F., Agosta C., Reich S. (2003)
Gen. Dent., 51, 450-454.
13. Filser F., Kocher P., Lüthy H., Schärer P., Gauckler
L. (1997) In: Bioceramics. Proceedings of the 10th
International Symposium on Ceramics in Medicine, Paris,
535
BIOTECHNOL. & BIOTECHNOL. EQ. 22/2008/1
France, (Sedel L., Rey C.), October 5-9, 1997. Oxford,
Pergamon, 10, 433-436.
14. Giordano R. (2003) J. Dent. Technol., 20, 20-30.
15. Hickel R., Dasch W., Mehl A., Kremers L. (1997) Int.
Dent. J., 47, 247-258.
16. Hintersher J., (1994) Europäische Patentschrift EP
0630622B1. June 23.
17. Hunter A.J., Hunter A.R. (1990) J. Prosthet. Dent., 64,
548-552.
18. Jiao T., Zhang F., Huang Z., Wang C. (2004) Int. J.
Prosthodont., 17, 460-463.
19. Lampe K., Luthy H., Mörmann W.H. (1996) In: CAD/
CAM, in Aesthetic Dentistry, Cerec 10 Year Anniversary
Symposium (Mörmann W.H.), Chicago, II: Quintessence,
463-482.
20. Leinfelder K.F., Isenberge B.P., Essig M.E. (1989) J. Am.
Dent. Assoc., 118, 703-707.
21. Liu P.R., Isenberg B.P., Leinfelder K.F. (1993) J. Am.
Dent. Assoc., 124, 59-63.
22. May K.B., Russell M.M., Razzoog M.E., Lang B.R.
(1998) J. Prosthet. Dent., 80, 394-404.
23. McLean J.W., Von Fraunhofer J.A. (1971) Br. Dent. J.,
131, 107-111.
24. McLean J.W. (1984) In: Dental Ceramics. Proceedings of
the First International Symposium on Ceramics (McLean
J.W.), Chicago: Quintessence Publishing Co., 13-40.
25. Mörmann W.H., Brandestini M. (2006) In: State of
the art of CADS/CAM restorations: 20 years of CEREC
(Mörmann WH) London, Quintessence, 1-8.
26. Noorani R. (2006) Hoboken, N.J., Wiley.
27. O’Neal S.J., Miracle R.L., Leinfelder K.F. (1993) J. Am.
Dent. Assoc., 124, 48-54.
28. Posselt A., Kerschbaum T. (2003) Intl. J. Comput. Dent.,
6, 231-248.
29. Probster L. (1996) J. Oral. Rehabil., 23, 147-151.
30. Sadoun M., Degrange M., Heim N. (1987) Journal de
Biomateriaux Dentaires, 3, 61-69.
31. Sarment D.P., Sukovic P., Clinthorne N. (2003) Int. J.
Oral Maxillofac. Implants., 18(4), 571-577.
32. Scotti R., Catapano S., D’Elia A. (1995) Int. J.
Prosthodont., 8, 320-323.
33. Sjogren G., Molin M., van Kijken J.W. (2004) Int. J.
Prosthodont., 17, 241-246.
34. Smay J.E., Cesarano J., Lewis J. (2002) Langmuir.,
18(14), 1639-1643.
35. Sorensen JA, Okamoto SK, Seghi RR, Yarovesky U.
(1992) J Prosthet Dent, 67, 162-173.
36. Stietzel R. (2001) Quintessenz Zahntech, 27 970-980.
37. Sykes L.M., Parrott A.M., Owen C.P., Snaddon D.R.
(2004) Int. J. Prosthodont., 17(4), 454-459.
38. Tinschert J., Natt G., Mautsch W., et al. (2001) Oper.
Dent., 26, 367-374.
39. Tinschert J., Natt G., Hassenpfl ug S., Spiekermann H.
(2004) Int. J. Comput. Dent., 7(1), 25-45.
40. Tsuji M., Noguchi N., Ihara K., Yamashita Y., Shikimori
M., Goto M. (2004) J. Prosthodont., 13, 179-183.
41. van Steenberghe D., Glauser R., Blombäck U.,
Andersson M., Schutyser F., Pettersson A., Wendelhag
I. (2005) Clin. Implant. Dent. Relat. Res., 7(1), 111-120.
42. Wang R.R., Andres C.J. (1999) J. Prosthet. Dent., 82,
197-204.
43. Weigl P., Kasenbacher A., Werelius K. (2004) In:
Femtosecond technology for technical and medical
applications (Dausinger F., Lichtner F., Lubatschowski H.,
Eds.). New York, Springer, 167-187.
44. Witkowski S. (2002) Zahntech. Mag., 6, 696-709.
45. Witkowski S. (2002) Quintessnz. Zahntech., 28, 958-971.
46. Witkowski S. (2002) Quintessenz. Zahntech., 28, 374-
386.
47. Witkowski S., Bannuscher R. (2002) Chicago: 51st
Annual Meeting of the American Academy of Fixed
Prosthodontics.
48. Witkowski S., Lange R. (2003) Schweiz. Monatsschr.
Zahnmed., 113, 868-886.
49. Witkowski S. (2005) Quintessence Dent Technol, 28, 169-
184.
50. Wohler T. (2004) Annual worldwide progress report. Fort
Collins, Colo.: Wohlers Associates; 2004. Available at:
“http://wohlersassociates.com/2004info.htm”. Accessed
July 27, 2006.
51. Young J.M., Altschuler B.R. (1977) J. Prosthet. Dent., 38,
216-225.