The emerging trends in ceramics, selective laser sintering, CAD CAM and its evolution. 3D printing of dental cermics

1. Vinay Pavan Kumar K
2nd year PG student
Dept of Prosthodontics
AECS Maaruti College of
Dental Sciences

2. Metal ceramic
prosthesis
Ceramic
prosthesis
Advances in
substructure
Advances in
Composition
Innovation in
processing
methods
Introduction
Innovation in
processing
techniques

3.  In 1903, Land : making of porcelain crowns
 In 1938, Pincus : Concept of ceramic veneers.
 In the evolution of ceramics the researchers
have strived hard to find innovative methods to
strengthen the most esthetic, but yet brittle.
 Modify in processing
 Modify the Composition
 Techniques of Substructure

4.  Conventional method
 Digital method
 Additive techniques
 Selective laser sintering
 3D printing
 Substrative techniques
 CAD CAM

5.  Condensing and Sintering
 Methods of condensation
 The Vibration technique
 The Spatulation technique
 The Brush technique
 Process of heating closely packed particles to
achieve inter particle bonding and sufficient
diffusion - ↓decrease surface area /↑ density of
structure
 Partial fusion or compaction of glass

7.  Selective laser sintering or selective laser melting
produces a 3D model by laser sintering or melting a
powder, layer by layer using a laser beam
 The laser beam locally raises the temperature close to
the melting point of the metal particle, to avoid
complete melting
 The platform is slightly immersed in the powder, and
powder thickness is controlled by a cylinder rolling on
the powder pool

8. After each new powder layer application, the laser
melting process is repeated until the 3D object is
completed
Oxidation of the metal can be controlled by
confining the melting to a sealed gas chamber.

9.  Greater liquid flow between the metal particles and
lower initial porosity results in the production of a low
porosity microstructure.
 The selective melting process should not completely
melt the metal particles; the melted particles will
aggregate and form larger spheres. Resulting in
major dimensional discrepancies in the final
workpiece
 To avoid this, the metal particles should be heated to
just below the melting temperature to ensure melting
is confined to the external surface of the particles
and fusion contact forms necks between the
adjacent powder particles

10.  3D printing extrudes material from a nozzle that
solidifies as soon as it is deposited on the
manufacturing platform
 The layer pattern is achieved through horizontal
nozzle movement and interrupted material flow.
 This is followed by vertical movement for the
sequential layer deposition.

11.  There are a range of materials that can be used
for 3D printing. This includes thermoplastic
materials, such as waxes, resins, or fused
filament
 Pass through a heated nozzle and solidifies
immediately after extrusion.
 Some systems allows multicolour production
 This approach is used in dentistry to fabricate
dental models, facial prosthesis patterns, acrylic
prostheses, investing flasks, and castable or
ceramic frameworks

12. 3D printing is distinguished from other fabrication
methods in the ability to print multiple materials at one
time

13.  3D printing overcome the problems created by
milling, such as surface cracking, shrinkage, and
material wastage
 high-strength zirconia frameworks have been
produced by 3D printing
 The reported strength was of the zirconia
prosthesis was 764MPa and the fracture
toughness was 6.7MPa
 submicron-sized pores were also detected and
attributed to the clogging of nozzles during the
injection of zirconia paste.

14.  Subtractive manufacturing is based on milling the
workpiece from a larger blank by a computer
numeric controlled (CNC) machine.
 The CAM software automatically translates the
CAD model into tool path for the CNC machine.
 This involves computation of the commands
series that dictate the CNC milling, including
sequencing, milling tools, and tool motion
direction and magnitude

15. Basic components of CAD CAM Involes:
 Digitalized Scanner
 Optical Scanner
 Mechanical scanner
 Design Software
 Processing Device or Computer numeric
control machine

16.  Optical Scanner
 Based on the principle of triangulation
 The light source and the receptor unit are in a
definite angulation in relation to each other
 Everest scan, Lava Scan, es1
 Mechanical Scanner
 The master cast is read mechanically line by line by
means of a ruby ball
 The 3D structure is measured
 Procera scanner

17.  Design Software
 Special software is provided by the
manufacturer for designing wide variety of
restorations
 Ranging from copings, full anatomical crowns,
inlays, onlays, FPDs frameworks, Adhesive
FPDs, telescopic primary crowns, post and
core.
 The information for such designing is stored in
various formats such as Standard
Transformation Language (STL)

18.  Processing Devices
 The dental CNC machines are composed of multi
axis milling devices to facilitate the 3D milling of
dental work pieces
 To facilitates production of very complex geometries
and smooth external surfaces dental restoration,the
milling machines combine burs with different sizes
 Milling is better accomplished in two steps:
 a rough milling is done at a low feed rate and high cutting
force while the final fine milling is performed at a higher
feed rate and reduced cutting forces
 The fine milling will reduce the chip thickness and
minimise surface roughness

19.  3 axis milling
In Lab (Sirona), Lava (3M ESPE),
Cercon brain(Degudent)
 4 axis milling
Zeno (Wieland-Imes)
 5 axis milling
Everest engine (KaVo), HSC
milling device (etKon)

20.  Dry Milling
 zirconium oxide blanks with low degree of presintering
 Advantages
 Economical
 no moisture absorption by the die ZrO2 mould
 no additional time is spent on drying ZrO framework
prior to sintering
 Disadvantages
 high shrinkage of framework
 Zeno 4030, Lava form and Cercon Brain

21.  Wet milling
 Milling diamond /carbide cutter protected by a
spray of cool liquid against overheating
against over heating of milled materials
 All metals and glass ceramics
 Zirconium oxide (if presintered)
 Reduction of shrinkage, less sinter distortion
 Everest (KaVo), Zeno 8060, in Lab(Sirona)

22.  Chair side Production
 Laboratory production
 Centralised fabrication in a production centre

23. • Chairside Economical
Restoration of Esthetic Ceramics
or
• computer-assisted CERamic
REConstruction
• Mörmann and Brandestini of
zurich university developed in
1980
• Dr. Alain Ferru, a young French
software engineer developed the
basic layout of the design
software in 1983

24.  The CEREC was first introduced in 1986.
 It consisted of a mobile unit containing :
1.A small camera
2.A computer with scan and
3.3-axis-of rotation milling machine
 The Old milling machine water-pressure driven.
 Clinical shortcoming
• Occlusal anatomy had to be created by the clinician
• Inaccuracy of fit or large interfacial gaps
• Clinical fracture
• Relatively poor esthetics

25.  Mobile unit containing small
camera, computer with scan
and 3-axis-of-rotation milling
machine with electric motor
 better and smoother cutting of
ceramic - better fitting
restorations
 Upgrading of software -
allows machining of occlusal
surface

26.  In 2003,three-dimensional virtual
display of the preparation, of the
antagonist and of the functional
registration became available
 The 2005 and 2006 versions
include the automatic adjustment of
a selected digital full-crown
anatomy to the individual
preparation, to the proximal
contacts and to the occlusion
 In 2006, a “step bur” replaced the
cylinder

28.  In 2007, a new generation of milling machine, MC
XL, was launched with increased precision which
resulted in attaching the crowns using dental
cement
 In 2009, a new imaging technology, the CEREC
Bluecam, which is based on short-wave blue light
 In 2011, the 4.0 version of the software simplified
the user interface with intuitive menu navigation
 In 2012 the CEREC Omnicam intraoral
camera,powder-free digital impressions in natural
colors.

29.  Lava System (3m Espe, Seefeld, Germany)
 Procera System
 Katana System
 Celay System
 Everest System
 Cercon System
 Dcs Precident

30.  ZENOTec (Wieland Dental & Technik GmbH & Co KG)
 DentaCAD system (Hint-ELs, Griesheim, Germany)
 Cerasys (Cerasystems, Buena Park, CA)
 Wol-Ceram (XPdent corporation, Miami, FL)
 BEGO Medifacturing (BEGO Medical GmbH,Germany)
 Turbodent System (U-Best Technology Inc, Anaheim, CA)
 Etkon system (etkon USA, Arlington, TX)
 iTero (Cadent, Carlstadt NJ, US)

31. SYSTEM
MARKET
LAUNCH
SCANNING
MECHANISM CAD PROGRAM CAM PROCESS PROCESS CENTRE
Cerec 3 2000 Optical
Yes, custom design
and database Fully automatic Chairside
Cerec InLab 2001 Laser
Yes, custom design
and database Fully automatic Dental Lab
DCS Precident 1989 Optical
Yes, custom design
and database Fully automatic Dental Lab
Procera 1993 Manual
Yes, custom design
and database Fully automatic New Jersey or Sweden
Lava 2002 Optical
Yes, custom design
and database Fully automatic Dental Lab
Everest 2002 Optical
Yes, custom design
and database Fully automatic Dental Lab
Cercon 2001 Laser No Fully automatic Dental Lab

32. CAPTEK System
 Capillary casting technology
 Principle - Capillary attraction to produce a gold
composite metal
 Composite alloy composed of 2 distinct alloy
phases
 Inner and outer surface contains 97% Au
 Available as Captek P and G

33.  Renaissance crown (Unikorn Ltd, Israel)
 Developed by Shoher and Whiteman
 Delivered in a fluted shape
 Swaged with a swaging instrument and
burnished on a die
 Flame sintered
 Veneered with porcelain and fired

34.  Predominantly glass based : Vita Mark I and II
 Particle filled glass : Inceram ,eMax
 Polycrystalline : lava, Procera, emax ZirCAD

35.  Conventional Sintered ceramics
 Castable ceramics
 Pressable/ injectable ceramics
 Infilterated/slip cast ceramics
 Machinable ceramics
 Printable ceramics

36.  Ceramic powders are mixed in water and the
slurry is built up in layers on die and the sintered
 The density of porcelain increases, it is associated
with the volmetric shrinkage of 30-40 %
 The sintered porcelain can be:
 Leucite reinforced glass ceramic
 Alumina based porcelain
 Magnesia based core porcelian
 Zirconia based porcelian

37.  Contains 45 vol% tertagonal leucite
 High modulus of rupture, compressive strength,
thermal contraction coefficient
 Heat treatment -1 hr at temp 705 to 980°C forms
sanidine( KAlSi the expense of the glassy matrix
 Crystallization of sanidine-translucent to opaque
 No special processing equipment
 Relatively high in vitro wear of opposing teeth

38.  Hi-Ceram (Vident, Baldwin Park, CA) Baked
directly onto refractory die (1994)
 Strengthening by dispersion of a crystalline phase
 Alumina -high modulus of elasticity (350 GPa),
fracture toughness (3.5-4 MPa)
 40-50% Alumina by wt
 Core baked on Pt foil and later veneered with
matched-expansion porcelain

39. The core material is obtained by reacting
magnesia with silica glass between 1100-1150 c
 Flexural strength is 131 Mpa due to formation of
Forsterite (Mg2SiO4)
 In-Ceram Spinell (alumina and magnesia matrix)
 the most translucent with moderately high
strength and used for anterior crowns

40.  Conventional feldspathic porcelain -tetragonal
Zr fibers included
 Zr undergoes a crystallographic transformation
from monoclinic to tetragonal at 1173°C
 Partial stabilization -CaO,MgO,Y2O3
 Transformation to stable monoclinic form -occur
under stress, associated with ↑ in slight particle
volume

41.  These are polycrystalline glass-ceramic
material supplied has solid ceramic ingots
 Used in fabrication ofCores/ full-contour
restorations by lost wax and centrifugal-casting
technique
 Crystals can be:
 Mica based
 Hydroxyaptite based
 Lithia based

42.  Dicor , was developed by Corning Glass Works and
marketed by Dentsply international.
 A full-contour transparent glass crown is cast at
1350 C, then is heat-treated at 1075 C for 10 hours
- “Ceramming”
 fracture resistance is 152MPa
 Indicated for Inlays,Veneers,Full crowns-accurately
 Crystals - less abrasive to opposing tooth structure

43.  a Castable ceramic developed by Kyocera, San
Diego, CA.
 Main crystalline phase -oxyapatite, transformable
into hydroxyapatite when exposed to moisture
(Hobo and Iwata, 1985)
 Refractive index, density, hardness, thermal
expansion, thermal conductivity similar to natural
enamel

44.  Developed by Uryu
 Composition: It contains mica crystals of NaMg3
(Si3AlO10) F2 and Beta Spodumene crystals of
LiO.AI2O3.4SiO2 after heat treatment
 The crystalline phase, lithium disilicate
(Li2Si2O5) makes up about 70% of the volume
 It has microstructure : small plate-like crystals
that are interlocking and randomly oriented
 the needle-like crystals deflect cracks and arrest
the propagation of cracks

45.  Supplied as ceramic ingots
 Melted at high temp and pressed into a mold
created using the lost-wax technique
 full contour/substrate for conventional feldspathic
porcelain buildup
 Leucite Based
 Spinell Based

46.  Developed by Ivoclar USA, Amherst, NY
 Leucite crystals ↑ resistance of crack propagation
 Ingot placed under plunger, assembly is heated
(1150°C) plunger presses molten ceramic into
specialized refractory mold (pressure- 0.3-0.4
MPa) -20 minutes -automatic press furnace
 Ingots -different shades- produced by sintering at
1200°C
 Flexural strength -improve under subsequent heat
treatments - 126 Mpa to160-182MPa

47.  Developed by Innotek Dental Corp, Lakewood,
 Magnesium spinel -major crystalline phase
 Initially introduced has "shrink-free" relied on
conversion of alumina and magnesium oxide to a
magnesium aluminate spinel
 Advantages -excellent marginal fit (Wohlwend et al)

48.  Dr. Micheal Sadorun (1980)
 Supplied as powder (aluminum oxide/ spinel) -
porous substrate
 Glass -infiltrated at high temperature into the
porous substrate
 Core ceramics:
In-ceram Spinell
In ceram Alumina
In-ceram Zirconia

49.  Prefired blocks of feldspathic or glass ceramics
 Supplied -ceramic ingots in various shades
 Machined restoration -stained and glazed
 Do not require further high-temperature
processing
 Based on composition
 Silica based
 Infiltrated ceramics
 Oxide based

50.  Cerec Vitablocs Mark I
 Feldspathic porcelain-large particle size – 10-
50 um
 Cerec Vitablocs Mark II
 Feldspathic porcelain reinforced with
Aluminium oxide- increased strength, finer
grain size (4 um) -less abrasive wear
 Sanidine -major crystalline phase within
glassy matrix - lack of translucency

51.  IPS e.max
 Includes lithium disilicate , high-strength
zirconium oxide
 Thin veneers to 10-unit bridges
 Esthetics and strength suitable for Press
technique and CAD-CAM
 Dicor MGC
 Fluorosilicic mica crystals in a glass matrix (70
vol% of crystalline phase)
 Mica particles size - 2 um
 Available as Dicor MGC light and Dicor MGC
dark

52.  Procesed in porous,chalky conditions and
infiltered with lanthanum glass
 Vita Inceram offers three variants:
 Vita Inceram Alumina : coping in anterior and
posterior region, 3 unit fpd frameworks in
anterior region
 Vita Inceram Zirconia : coping in anterior and
posterior region, 3 unit fpd frameworks in
anterior and posterior region
 Vita Inceram spinel : highly esthetic, anterior
copings

53.  Aluminium oxide:
 milled in pre sintered state
 sintering temp : 1520 c
 coping in anterior and posterior region, 3 unit
fpd frameworks in anterior region
 Yittrium stabilized Zirconium oxide
 high flexural strength and fracture toughness
 Framework of posterior FPDs and implant
abutments

56.  3D printed ceramics is relatively rudimentary when
compared with a traditional lab ceramic system
 3D printing ceramics differ from regular 3D printing
 Once you "print" out your crown you still have to
fire your ceramic 3D printed object in the oven
 The 3D model is rescaled 40% larger than the
original scanned model to obtain the correct size
after shrinkage

57. Green copings & crowns printed with ProMetal binder and Sumitomo AA-18 alumina
Green and post sintered crown parts

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Materials, 12th edition, India, Elsevier
Publishers, 2006, pp 443-477
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ceramics,TPDI 2010 vol 1 no 2 pp 38-44

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