Cad cam dentistry/ certificate programs in dentistry

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

INTRODUCTION
 The introduction of CAD/CAM systems to restorative
dentistry represents a major technological breakthrough.
 It is now possible to design and fabricate ceramic
restorations at a single appointment, as opposed to the
traditional method of making impressions, fabricating a
provisional prosthesis and using a laboratory for
development of the restoration.

 CAD/CAM generated restorations save the dentist and
patient time, provide an esthetic restoration, and have the
potential for extended wear resistance.

EVOLUTION OF THE CAD/CAM SYSTEMS
 Optical scanning and computer generation of restorations
were attempted as early as 1971 (Altschuler, 1971/1973).
 With the continued improvement in the technology, a
number of systems were currently being investigated at
this time (Duret et al,1988;Williams,1987; Rekow,1987;
Brandestini et al,1985; Duret and Preston,1991).

 The teams most actively pursuing this technology of
CAD/CAM in dentistry were the French group, headed by
Dr. Francois Duret, whose system is currently being
investigated at the University of Southern California;
 The DentiCAD unit at the university of Maryland, led by Dr
Dianne Rekow;
 And the Brandestini / Mormann unit,Working on the
CEREC System.

 This French System - one of the earliest - was first shown
as a prototype in 1983.
 This System uses lasers to optically scan the image or
preparation in the patient's mouth.
 Multiple images from different angles are obtained with
an optical probe.The Computer then creates a three
dimensional composite view of the tooth on which the
operator can trace the margins of the preparation.

 This system is capable of milling inlays, full crowns, and
three – unit fixed partial dentures.
 With this system dentists would most likely have to
maintain the probe in the dental office and transmit data
to a central laboratory for prosthesis fabrication.

 Dr Dianne Rekow originally used a technique described as
being "Stereo photogrametric".
 It used a series of black and white photographs to create
the tooth contours necessary to rebuild missing parts of
the clinical crown.
 The information was converted to digital form, which was
used by a computer to reconstruct the crown.

 The third system, the CEREC system, developed in Zurich,
Switzerland,can fabricate onlays, ¾ Crowns, 7/8 crowns,
and veneers.
 This system allow the clinician to restore the tooth with an
indirect, permanent restoration in one appointment.This
is done without the use of an impression or the assistance
of a laboratory technician.

 It consists of three basic components: a small camera, a
computer with screen and three axis of rotation milling
machine.
 A new version of the milling motor has been introduced. It
uses an electric motor ("E" version) to drive the milling
wheel instead of the water-pressure-driven "hydro"
version.
 This provides a smoother cutting of the ceramic, hence a
better fitting restoration.

MATERIALS USED FOR CAD/CAM RESTORATIONS:
 Chair side Materials
 Laboratory based materials
Materials fabricated for use in CAD/CAM systems must be
able to be milled rapidly, resist machining damage and be
finished easily before placement.

CHAIR SIDE MATERIALS
 CEREC 3 (Sirona Dental Systems, Germany) is the only
chair side system available.
Materials available for use with CEREC3 include:
a.feldspathic porcelain-based ceramics
Vitablocs Mark II (Vita Zahnfabrik,Germany)
ProCAD (lvoclar Vivadent, Lichtenstein) &
b.Resin-based composite block: Paradigm MZIOO (3M
ESPE)

Vitablocs mark II:
 This contains sanidine (KAISi3O8) as a major crystalline
phase within a glassy matrix.
 They are fabricated using fine-grained powders that
produce a nearly pore-free ceramic with fine crystals.This
results in improved polish ability, decreased enamel wear
and increased strength.

 Strength of this material is approximately 130 Mpa when
polished & about 160 Mpa or higher when glazed, which is
about twice as strong as conventional feldspathic
porcelains.
 The material has excellent esthetic qualities and can be
characterized using external stains and a porcelain add-on
kit.

ProCAD blocks:
 ProCAD blocks have a fine leucite crystal structure (about
5 to 10 micrometers in size) and can be further
characterized using external stains.
 Strength properties are similar to those ofVitablocs Mark
II blocks.

Paradigm MZ1OO:
 This is a resin-based composite with micro zirconia-silica
fillers.
 Its block form has mechanical properties superior to those
of the conventional Restorative direct resin-based
composite.

 All of these blocks have a fine particle-sized
microstructure that helps resist machining damage,
improve mechanical properties, decrease polishing time
and improve wear kindness of the finished restoration.
 They are mono chromatic. A variety of block shades are
available to match the patient's natural dentition and
these materials exhibit a "chameleon" effect in that they
tend to blend in with the surrounding tooth structure.

LABORATORY-BASED MATERIALS
Several materials are available:
a) Vita In-Ceram (Vita Zahnfabrik)
b) IPS e.max CAD (IvoclarVivadent)
c) Yttria partially stabilized zirconia materials (so called
"pure" zirconia)
>Vita InVizion system(Vita In-CeramYZ)
> IPS e.max ZirCAD (IvoclarVivadent)

Vita In-Ceram Materials:
 They belong to a class known as "interpenetrating phase
composites".
 They involve at least two phases that are intertwined and
extend continuously throughout the material.
 Porous blocks of Vita In-Ceram materials are milled to
produce a frame work.Then the blocks are infused with a
glass in different shades to produce a 100% dense material
which then is veneered with porcelain.

Vita In-Ceram is available in 3 types:
 Vita In-Ceram Spinell
 Vita In-Ceram Alumina
 Vita In-Ceram Zirconia
 Vita In-Ceram Spinell is the most translucent with
moderately high strength (350 Mpa) for anterior crowns.
 Vita In-Ceram Alumina with high strength (450-600Mpa)
and moderate translucency for anterior and posterior
crowns.
 Vita In-Ceram Zirconia with high strength (700Mpa) and
lower translucency for anterior and posterior crowns.

IPS e.max CAD:
 This is a lithium disilicate glass ceramic similar to IPS
Empress 2 (IvocIar Vivadent) in strength (320Mpa) and
microstructure.
 In block form it is only partially crystallized to facilitate
machining. After milling the framework is fired at 850 C for
0.5 hour, which completes the crystallization.
 This may be used for crowns, inlays and onlays.

Partially Stabilized Zirconia Materials:
 It is reliable material for high-stress areas, such as
posterior region of the mouth.
 Owing to its high strength and toughness, zirconia is a
universal ceramic restorative material that can be used
any where in the mouth.

 Zirconia may exist in several crystal types depending upon
the addition of minor components such as calcia,
magnesia, yttria or ceria.
 Specific phases are said to be stabilized at room
temperature by the minor components. If about 8-12%of a
component is added, a fully stabilized cubic phase, such as
cubic zirconia is produced.
 If smaller amounts (3-5% weight ) are added, then a
partially stabilized tetragonal zirconia phase is produced.

 Under stress, the phase may change to monoclinic phase,
with a subsequent 3% volumetric size increase.
 This dimensional change takes energy away from the
crack and can stop its growth and is called
"transformation toughening".
 Natural teeth often contain many cracks in the enamel
that do not propagate through the entire tooth.These
cracks can be stopped by the unique interface at the
enamel-dentin junction.

 The ability to stop the cracks as they enter the zirconia
core structure mimics the effect seen in natural teeth.
 Transformation toughening helps give the zirconia its
excellent mechanical properties: high flexural strength
(1.0 giga pascals) and toughness.
 Another beneficial property is its good biocompatibility.

 The Vita In-CeramYZ and IPS e.max ZirCAD blocks are
partially fired to produce a chalky block that is milled
easily.
 The framework is milled oversized to account for firing
shrinkage of 20-30 % and fired at about 1,500 C to fully
densify the zirconia.
 Each block has a bar code that tells the computer the
density at which to properly mill the framework oversized.
 Systems such as Lava (3M ESPE), Cercon Zirconia
(Dentsply), and Everest (KaV0 Dental) use this approach.

VARIOUS CAD/CAM SYSTEMS:

1. CEREC SYSTEM: (Computer-assisted CERamic
REConstruction)
 Dr.Brandestini produced the first design for the CEREC 1
unit and intra oral camera.
 The CEREC 2 and 3 units, as well as the CEREC inLab , and
extraoral scanner and the associated software versions,
were developed by CEREC teams at Siemens and Sirona
(Bensheim, Germany).

Cerec 1- 1985……first chair side inlay
Cerec 2- 1994…..partial & full crowns
Cerec 3- 2000….three unit bridge
2003….four unit bridge
2005….automatic occlusal adjustments..

Clinical Procedure for the CEREC System:
Preparation Design:
 There are certain prerequisites for the preparation design
for a CEREC restoration.The conventional inlay design
must be modified to best use the capabilities of the milling
device.
 The computer cannot accurately read bevels, convexities,
steps or undefined angles; it is therefore imperative that
the prepared walls be as straight as possible.The ideal
occlusal wall can be vertical, slightly convergent, or
slightly divergent to the occlusal cavosurface.

 If an undercut portion is generated during the preparation
procedure, it will be blocked out during imaging and
become filled in with the luting composite resin.
 The occlusal cavosurface should have a smooth, flowing
outline.

 Floors and walls that are relatively flat give the computer
an image that is more discernible and allow a much more
intimate fit, especially at the margin.
 Irregular surfaces make it more difficult for the milling
machine to accurately mill the ceramic material.

The Optical Impression:
 The surface of the prepared tooth often lack sufficient
reflectivity. It is therefore necessary to coat the
preparation with a special powder that has the proper
light reflective ability.
 A hand-held camera is placed over the prepared, powder-
coated cavity to obtain a fixed image on the computer
screen.The camera is adjusted until a clear image and all
aspects of the cavity can be seen.

 It is essential to position the camera over the long axis so
that the computer can read all internal walls and
cavosurfaces equally.
 At this point, the operator, by releasing the foot pedal,
"freeze frames" the preparation on the screen.
 The focal length of the camera is 10 mm; any depth
greater than 10 mm will not focus properly and an ill-
fitting restoration subsequently will be generated.

Computer-Generated Restoration Design:
 The restoration is designed from the image shown on the
computer screen by using a series of icons or symbols.
 The operator can electronically design the restoration by
moving a cursor along the limits of the preparation,
thereby defining its boundaries.

 The procedure can be stopped at any time and edited to
override the computer and allow the operator to correct
the electronically generated features.
 Once the restoration has been designed, the computer
develops the on screen 3-dimensional model or image of
the inlay, onlay or veneer.

 All of the information generated is stored automatically
on a programmed floppy disk. Up to 3 images may be
stored on each disk.
 The design phase usually takes from 2 to 8 minutes.This is
even possible when designing multiple cusp replacements
or veneers.

Milling Procedure:
 After all the data have been supplied, the computer
selects the size & shade of ceramic block to be used in the
milling process.
 Three materials can be used with this system:
Vita MarkII
DicorMGC
ProCad

 The material is mounted on a metal stub, which allows it
to be inserted into the milling unit. Once the material is
inserted, the small window is closed and the milling device
is activated.
 The milling is accomplished by a three-axis-of rotation
cutting machine, which mills 25 micro mm slices.

 A diamond wheel is driven by the electric motor, which
generally takes 4 to 7 minutes to complete the procedure.
 The milling allows for occlusal contours of the cuspal
inclines, marginal ridges and proximal contours.
 It does not provide for internal and secondary occlusal
anatomy. This is developed by the operator intraorally
after the inlay has been cemented.

Clinical Placement:
 Because breakdown primarily occurs at the tooth-
restoration interface, the interfacial gap and luting agent
play an important role in longevity of the restoration.
 The gap should be kept under 100microns, particularly on
the occlusal surface.

 Cementation involves etching the tooth with a 37%
solution of phosphoric acid for 20 seconds.
 The tooth is then washed and dried and a bonding agent is
applied.
 The ceramic restoration is etched on its undersurface,
outside the mouth.

 Currently, the two materials of choice are the Dicor
ceramic material andVita porcelain.
 The Dicor is etched with ammonium bifluoride, and the
Vita is etched with a buffered hydrofluoric acid gel.
 With either material, a silane coupling agent must be
applied to the undersurface for better retention to the
composite resin luting agent.

 A dual-cure microfill composite resin luting agent is used
to bond the inlay, onlay or veneer.
 The Brasseler system of diamonds is excellent to make the
final finishing and polishing using diamonds, 12 and 30
bladed carbide burs, rubber points and diamond paste.

Advantages of the CEREC System:
 Single appointment
 No impression
 Bonded restoration for strength
 Reduced marginal gap
 Wear hardness similar to enamel
 Less fracture of the inlay, because it is milled from a solid,
homogeneous block

 Excellent polishing characteristics
 Improved esthetics
 Less reduction of tooth structure, hence better
periodontal health
 Bonded restorations enhance tooth strength
 Preparation, fabrication, cementation and polishing
normally accomplished in 1 to 1.5 hours.

2. THE CELAY SYSTEM:
 It was developed by Dr. Stefan I.Eidenbenz at the
University of Zurich, is a variation on the direct-indirect
restoration concept but without the need for a laboratory
technician.
 An inlay or onlay preparation is made for the
compromised tooth, but, instead of a conventional
impression, a direct process is used.

 A moldable precision imprint material is molded directly
inside the mouth in the cavity preparation, where it is
adjusted for occlusion, contact relations, and marginal
integrity.
 The material then undergoes a light hardening or curing
process before it is removed from the tooth to serve as a
prototype model to be copied and reproduced in ceramic
on a unique milling system developed by Claude Nowak of
MicronaTechnology,Germany.

Design of Milling Machine:
The milling center has two distinct aspects:
 In one half the model to be copied is centered in a holder,
where it is manually scanned.
 A second part of the Milling machine contains a rotary
turbine with various cutting tools.

 The resin pattern (pre-inlay) is held for overall surface
tracing in a dry chamber on the left side of the unit.
 A ceramic blank is machined using a high speed turbine in
the wet carving chamber on the right side.
 A pantographic arm is situated between two stations and
acts as a geometric transfer mechanism to link the 3-
dimensional movements of the tracing device along the
eight axes provided with the milling device.

Pre-Inlay Fabrication:
a. Direct Method:
 Control of marginal excess and carving occlusal surfaces is
difficult because of the lack of color contrast with the
natural tooth.
 Also, light-activated pattern materials set rapidly, and
their rigidity makes removal difficult.

 A three-component composite material (ESPE-CELAY
Dent, Germany) is developed to achieve a more "elastic"
setting characteristic that can be hardened later using a
blue light.
 A dead soft steel matrix band with the necessary plasticity
can be used to facilitate proximal contouring.

b. Indirect Method:
 A light-activated composite material is chosen for
modeling on the die where undercuts can be more easily
recognized and eliminated.
 Longer working time allows the technician to form natural
occlusal surfaces for more complex restorations.
 This material also is colored with dark blue pigments but
with less light activator to delay setting and provide more
manipulation time.

Clinical Procedure:
 Tooth preparation follows the accepted rules for adhesive
inlay restorations.
 The cavity is cleaned and a steel matrix band is secured
using proximal wedging. A thin coat of a separating
medium is applied to the prepared tooth structure.

 The three component resin is adapted to the cavity walls
using finger pressure and a ball gauge.
 A special composite spatula (CELAY spatula, ESPE) is used
for final forming.
 Occlusal contacts are checked during maximum inter
cuspation as well as during excursive movements.

 While the material is still elastic after the initial setting, a
manipulative device(Visioform,Espe)is luted to the surface
pattern to facilitate removal and left attached until after
final polymerization using the blue light.
 When using the indirect procedure, an elastomeric
impression of inlay preparations is needed to fabricate
working cast.The stone die is prepared.

 After the material has been adapted, the die is replaced
into the mounted working cast to adjust proximal and
occlusal contacts.
 After all contact areas have been adjusted, the pattern is
light activated.

Milling Procedure:
Pattern is mounted on a jig in the left side of the unit.
The following milling instruments and polishing
instruments are used:
 A coarse diamond disk with a grit size of 126 microns for
efficient bulk reduction.
 A finishing diamond disk with a grit size of 64 microns for
precision milling of the final contour.
 Round tip diamonds with a grit size of 64 microns for
narrow concavities, i.e., secondary occlusal anatomy.

Procedure:
 For economy, the smallest ceramic blank possible(Vita-
CELAY Blank) is mounted.
 To reduce overall carving time, the bulk of excess ceramic
material is trimmed with the coarse diamond disk to a
rough estimate of the desired restoration.

 A highly filled, hybrid, dual-activated luting composite
resin agent has been used for cementation of direct as
well as indirect inlays.

Advantages of the CELAY System:
 A precisely fitting ceramic restoration can be developed in
one patient session.
 A ceramic restoration can be developed without the need
for a laboratory technician.

 The restoration is developed in factory-fired high grade
porcelain.
 The processing time required is very short.
 A small inlay can be milled in 3 minutes, a mesio occluso
distal inlay in less than 8 minutes, and a complete onlay in
12 to 13 minutes.

3. PROCERA ALLCERAM SYSTEM:
 It involves an industrial CAD/CAM process.
 The die is mechanically scanned by the technician, and the
data are sent to a work station where an enlarged die is
milled using a computer-controlled milling machine.

 This enlargement is necessary to compensate for the
sintering shrinkage.
 Aluminium oxide powder is then compacted onto the die,
and the coping is milled before sintering at very high
temperature (>1550C).
 The coping is further veneered with an aluminous ceramic
with matched thermal expansion.

Step by Step Procedure:
 Tooth preparation follows all ceramic guide lines.
 The cast is made in the conventional way but the die is
ditched to make the margin easier to identify during
scanning.
 The die is mapped using a contact scanner.

 The shape of the prepared tooth is transferred to the
computer screen.
 The design of the restoration is transferred to the
manufacturer via computer line.
 The production process starts with milling and enlarged
die to compensate for the sintering shrinkage.
 An enlarged high-alumina coping is milled that shrinks to
the desired shape after sintering.

 The coping is returned to the laboratory, and body and
incisal porcelains are applied in the conventional manner.

NOBEL PROCERA
 Can be used on any anterior or posterior teeth, implants or
abutments.
 Best precision fit. Production accuracy of < 10 microns.
 Highly biocompatible & homogeneity.
 Materials used are zirconia (1120 MPa), alumina ( 600-
700MPa),Titanium ( 345- 860 Mpa)

Advantages:
a) Industrial fabrication.
b) High quality product & long term success.
c) Veneering thickness is uniform to prevent chipping.
d) Eliminates time consuming adjustments.
e) Broad prosthetic versality.
f) Tooth preparation & cementation is same as conventional.

 Excellent esthetics
 Excellent flexural strength.
 Excellent material homogeneity.
 Innovative coloring technique.
 Automatic cut back function.
 Customized trans mucosal profile.

4. COMET SYSTEM: (COordinate MEasuring
Technique)
 The COMET system allows the generation of a 3-
dimensional data record for each super structure, with or
without the use of a wax pattern.
 Optical, full surface, high speed digitization allows for wax
patterns of the final restoration to be recorded with speed
and precision.

 The COMET system uses a pattern digitization and surface
feedback technique, which accelerates and simplifies the
3-dimensional representation of tooth shapes while
allowing individual customization and correction in the
visualized monitor image before milling.
 The final restoration is then milled or ground from any
desired material by an associated milling unit.

Three steps are involved:
a) Digitizing data from the die surface or a wax pattern
surface.
b) Mathematical processing of data to program the milling
machine, and
c) Milling of copings, crowns, multiunit restorations, and
implant abutments.

Three procedural options are currently feasible:
1.
 An impression is obtained of the prepared tooth, master
cast poured in die stone.The planned restoration is then
waxed and the surface of the completed wax pattern
opto- electronically scanned and digitized.
 After removing the wax pattern from the die, the surfaces
of the prepared tooth in the cast are digitized as well.
 The individual views are linked by special software.
 Thus, single crowns) inlays and onlays can be made of
various metals or metal alloys, ceramics or resin materials.

2.
 The prepared tooth surface and contact and occlusal
surfaces of the adjacent and opposing teeth on the master
model are digitized.
 A CAD program is used to generate the new crown
surface; whereas, the crown interior is computed from the
prepared tooth surface data.

3.
 For the production of custom copings, it is sufficient to
digitize the prepared tooth on the master cast.
 External and internal surfaces of the copings are
computed by the software.

Digitizing:
 The COMET system is characterized by an optical sensor
that is capable of capturing between 400,000 and 1 million
data points simultaneously, depending on the resolution
of the camera used.
 Automatic measurement software determines how many
views must be taken to reconstruct the object exactly.The
various views are then linked together in the computer to
form the tooth or prepared surface.

Data Processing:
 The surface of an object to be measured consists of a
number of points.
 Because only a finite number of points can be digitized
opto- electronically, a feature of the software computes
the non digitized points and generates a 3-dimensional
image of the surface of the object to be measured.

 To make single crowns, an additional program is available
for customization of occlusal surfaces whenever it is useful
to do so without a wax pattern.
 For manufacturing copings, the prepared tooth surface is
digitized, computed and shown on the monitor. Coping
dimensions are then calculated and the finish line is
verified.

Milling:
 This milling machine, especially developed for dental
applications, is equipped with a multiple-axis, high speed
milling/drilling tool, with interchangeable cutters driven
by computerized velocity and rotating at a maximum
speed of 60,000 rpm.
It takes place in4 steps:
 Rough milling of outside surfaces for bulk material
removal

 Fine outside milling to finalize the outer contours and
surfaces of the restoration.
 After rotating the work piece by 180 degrees, rough
internal milling.
 Fine inside milling to produce accurate internal fitting
surfaces of restoration.

5. CICERO SYSTEM: (Computer Integrated
Ceramic RecOnstruction)
 described by Denisson.
 It uses optical scanning, ceramic sintering, and computer-
assisted milling techniques to fabricate restorations with
maximum static and dynamic occlusal contact relations.
 With the CICERO CAD/CAM method, crowns and inlays
with different ceramic layers-such as high-alumina core,
dentinal, and incisal porcelain for maximal strength and
enhanced esthetics are produced.

PROCEDURE:
1. Scan-model preparation:
 An impression is made of the arch with the prepared teeth
and poured in gypsum.
 The gypsum cast of the model that contains the
preparation is marked with black/white contrast for
unambiguous scanning of the margin.

Optical scanning:
 The first step is an optical impression obtained by laser
scanning of the cast.
 CICERO CAD/CAM system makes use of a fast laser-stripe
scanning method to measure the 3-dimensional geometry
of the preparation, its immediate surroundings, and the
opposing teeth.
 A straight laser stripe, which is projected onto the cast, is
deformed by the 3-dimensional occlusal geometry of the
tissues; this deformation is used by the computer to
determine the actual 3-dimensional positions of those
points on the surface of the tissues.
 Camera scans the projected line.

Design:
 The crown form is designed by selecting the proper tooth
element from the library, modeling the crown on the
screen to fit, with the remaining dentition, and making
final adjustments to the proximal contacts with the
computer.

 The appropriate tooth is chosen by the operator from an
extensive collection of generic forms of theoretical teeth
in the program's library.
 When an intact mirror element can be found in the arch, it
can be scanned and used as a standard tooth.

 The lingual and buccal boundaries are clicked in and
dragged with the mouse to shape the tooth so that it fits
in a natural-appearing row with the adjacent teeth.
 Thus, the external contours of the new crown can be
adjusted interactively with the mouse, in much the same
way that porcelain is built up by brush.

 After the crown has been fitted into the row, the computer
adjusts the mesial and distal contacts to within +-0.02mm
of the adjacent teeth.

Design of crown layer buildup:
 After the interior and exterior tooth surfaces have been
designed, several interface surfaces between cement and
ceramic core and between dentin and incisal porcelain are
defined.
 The CICERO software calculates the interior surface
corrected with marginal gap (0.03 mm), overall cement
thickness (0.05-0.1 mm), and ceramic core-die cement
thickness (0.02mm) as specified by the operator.

6. OTHER CAD/CAM SYSTEMS:
1. DCS Precident
 It is consists of a Precision laser scanner and Precimill
CAM multi tool milling center.The DCS Dentform
software automatically suggests connector sizes and
pontic forms for bridges.
 It can scan 14 dies simultaneously and mill up to 30
framework units in 1 fully automated operation.

 Materials used with DCS include porcelain, glass ceramic,
In-Ceram, dense zirconia, metals, and fiber-reinforced
composites.
 This system is one of the few CAD/CAM systems that can
mill titanium and fully dense sintered zirconia.

2. Lava:
 Introduced in 2002, it uses a laser optical system to
digitize information from multiple abutment margins and
the edentulous ridge.
 The Lava CAD software automatically finds the margin
and suggests a pontic.
 The framework is designed to be 20% larger to
compensate for sintering shrinkage.

 After the design is complete, a properly sized semi
sintered zirconia block is selected for milling.
 The block is bar coded to register the special design of the
block.

 The computer controlled precision milling unit can mill out
21 copings or bridge frameworks without supervision or
manual intervention.
 Milled frameworks then undergo sintering to attain their
final dimensions, density, and strength.
 The system also has 8 different shades to color the
framework for maximum esthetics.

3. Everest:
 Marketed in 2002, it consists of scan, engine, and therm
components.
 In the scanning unit, a reflection-free gypsum cast is fixed
to the turntable and scanned by a CCD camera in a 1:1
ratio with an accuracy of measurement of 20 microns.

 A digital 3D model is generated by computing 15 point
photographs.
 The restoration is then designed on the virtual 3D model
withWindows-based software.

 Its machining unit has 5-axis movement that is capable of
producing detailed morphology and precise margins from
a variety of materials including leucite-reinforced glass
ceramics, partially and fully sintered zirconia, and
titanium.
 Partially sintered zirconia frameworks require additional
heat processing in its furnace.

4. Cercon
 The Cercon System is commonly referred to as a CAM
system because it does not have a CAD component. In this
system, a wax pattern (coping and pontic) with a
minimum thickness of 0.4 mm is made.

 The system scans the wax pattern and mills a zirconia
bridge coping from presintered zirconia blanks.
 The coping is then sintered in the Cercon heat furnace
(1,350C) for 6 to 8 hours.

CLINICAL PERFORMANCE OF CHAIRSIDE CAD/CAM
RESTORATIONS:
 CEREC 3 is the only chair side system available.
 Since the CEREC-generated restorations are placed in a
single appointment, some postoperative sensitivity will be
the result of occlusal interferences.

 Restoration Fracture:
Insufficient porcelain thickness is one of the major
contributors to the fracture of porcelain restorations.
 Color Match:
A custom stain and glaze technique can be used to modify
the color of a porcelain restoration to ensure an esthetic
match to a natural tooth.

 Margin Adaptation:
It is expected that well-fitting margins will maximize the
longevity of restoration. Resin-based composite cement
wear at the margin leading to ditching has been reported
in almost all clinical evaluations of CEREC-generated
inlays.
The margin wear is a surface phenomenon and is not
accompanied by a breakdown in the adhesive bond to the
tooth.

 Clinical Longevity:
Ceramic fracture was the overwhelming primary reason
for failure, followed by supporting tooth fracture. Ceramic
fracture is thought to be a result of occlusal stress or
insufficient ceramic thickness.

CONCLUSION
We feel proud that we have been using dental
restorative and prosthetic devices to recover and maintain
the oral function and health of patients.
There is no doubt that the application of CAD/CAM
technology in dentistry provides innovative, state-of-the-
art dental service, and contributes to the health and QOL
of people in aging societies.
Therefore, we in the field of dentistry must not
procrastinate in implementing new technology for the
benefit of our patients.

Thank you
For more details please visit

Cad cam dentistry/ certificate programs in dentistry

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