CAD-CAM

By. Ahmed Hamarsha

 Technological and biomechanical improvements has
provided the dentists with a new approach to dental
restorations with great precision and improved
mechanical properties, this is achieved by machining
and industrially manufactured restoration from
blocks/disks

 Machining could be mechanical such as copy milling or

automated like CAD-CAM
Stages and steps in milling an inlay starting from a
ceramic block
 Copy milling
 Wax or resin replica of the restoration is fabricated, a
scanning tool traces the replica that serves as the exact
template for copy milling the restoration
System that applies the copy milling
 Therefore it involves manual fabrication of the replica
and mechanical scanning and manufacturing of the
restoration
 CAM: computer aided manufacturing
 Similar to copy milling
 Replica is fabricated by the technician, then it is
scanned by a laser scanner, then the data is transformed
to a computer and then a restoration is fabricated
according to the data in the computer
 Materials that are most commonly used in CAM
technology are subjected to 20% shrinkage after firing,
therefore data obtained from scanning the data are
adjusted to compensate for this shrinkage
 Computer aided design/computer aided
manufacturing CAD-CAM:
 it is the process of fabrication of a prosthesis through
the use of computer aided design and computer aided
manufacturing
 It is achieved by scanning the prepared tooth or the prepared
die, transfers the data to a computer software that designs the
restoration and sends it to a milling machine to fabricate the
prosthesis
 Place of production of the prosthesis:
 Could be in three possible locations
 1.Chairside: all component of the CAD-CAM are located in the
dental clinic, the cavity or the tooth preparation is scanned by an
intraoral scanner that transfers the cavity dimension and
geometry to the computer software to design the prosthesis, the
information are then transferred to a milling machine to produce
the restoration
 Example is the Cerec 1 and 2 systems
 2. In the dental laboratory:
 Dentist sends an impression to the dental laboratory, a model is
then prepared, a three-dimensional scanning of the prepared die
is carried out and again transfer of the data to the software for
designing, followed by the fabrication of the prosthesis by
milling, example is Cerec InLab
 3. Fabrication in a centralized production center :
 Fabrication of the prosthesis or the core is in a specialized
milling center
 the surface of the prepared die is scanned by a special scanner,
the data is then transferred via a modem to a distant production
center, the prosthesis/core is fabricated there and sent back to
the laboratory for further veneering. Example is the Procera
system
All CAD/CAM systems have three main components : 

 1. Scanner
 2. Software for designing
 3. Processing Machine (milling or addition)
Scanning of the dental cast
 Components of CAD-CAM
 All CAD/CAM systems have three main components
 1. Scanner that transforms geometry (shape and dimensions)
and converts it to digital data to be processed by the computer
 A) Optical scanner: scans the prepared tooth or the
die with laser or white light

 B) mechanical scanner: master cast is read mechanically and

line by line through a ball that rotates around the die and
registers 360 dots in each rotation and can register 25000-
50000 dots depending on the height of the tooth and the
number of rotations in an estimated reading time of 3
minutes this results in a high accurate scanning capability
Mechanical scanner of Procera
 This scanner is only provided by Procera system/
Nobel Biocare
 Disadvantages:
 The scanner is very expensive due to complicated
mechanics
2. Software that process data and depends on the
application produces data set to fabricate the
prosthesis
3.Machine that produces the prosthesis depending on the
data fed by the computer software.
Many types available:
4 axes – 5 axes, Wet or dry
 The materials that could be used are in
CAD/CAM systems are:
 Metals: metals like Titanium and chrome cobalt
could be processed using milling machines
 Feldspathic porcelain blocks such as VitaBlocks
Mark II
 Pure alumina : such as In ceram AL Block
 Zirconia (ZrO2) in the form of Yttrium
stabilized zirconium oxide an example is YZ
cubes
 Glass ceramics (IPS emax blocks)
Digital Designing of the
restorations on the
Cad-Cam system I
Lecturer : Dr. MUSTAFA ATATRA
Injectable Pressable System
(IPS)-Empress
Lecturer : Ahmed Hamarsha
 Ceramic Ingot Press furnace
Burnout Furnace

Press ring
Cylindrical Crucible Former Press plunger/ Pushing rod
3.
1. High Opacity (HO)

2. Medium Opacity (MO)

All-ceramic Materials Overview

AHMED HAMARSHA
 Study Resources

⚫ Contemporary fixed porsthdontics by Rosenstiel (2016): Chapter 25

⚫ Lecture notes
⚫ Papers attached in E-learning
 All-ceramic Systems

⚫ Started with the platinum foil technique (developed over 100 years ago). The platinum
foil supported the porcelain during firing and prevented distortion. Then it is removed
prior cementation.
⚫ Nowadays, with the rise of new materials (i.e. Zirconia and Lithium disilicate); hot-
pressing, slip-casting and milling (using CAD/CAM) are the most popular fabrication
techniques.
⚫ All-ceramic restorations may be fabricated in several ways.
 All-ceramic Systems

Aluminous Core Ceramics

⚫ Considered to be a high-strength ceramic core.

⚫ Introduced to dentistry in 1965 by McLean and Hughes

⚫ They advised using aluminous porcelain (aluminum oxide (alumina), which is composed
of crystals dispersed in a glassy matrix due to the fact that alumina has high fracture
toughness and hardness. The technique involved:
1. An opaque inner core containing 50% by weight alumina for high strength.
2. Veneering material with matching thermal expansion. It consisted a combination of
esthetic body and enamel porcelains with 15% and 5% crystalline alumina.

⚫ The final restorations were approximately 40% stronger than those fabricated with
traditional feldspathic porcelain.
 All-ceramic Systems

⚫ Later on, high-strength core frameworks for all-ceramic restorations were produced with a
slip-casting procedure/technique, i.e. VITA In-Ceram.

⚫ A technique originally used to make sanitary ware in the ceramic industry.

⚫ In this technique, the slip is an aqueous suspension of fine ceramic particles in water with
dispersing agents.

⚫ The porous refractory die absorbs the water from the applied slip which leads to the
condensation of the slip on the die.

⚫ The refractory die is then fired at a high temperature (1150°C) and shrinks more than the
condensed slip; allowing easy separation after firing. The fired porous core is then glass
infiltrated, a unique process in which molten glass is drawn into the pores by capillary
action at a high temperature.
 All-ceramic Systems

⚫ Restorations processed by slip-casting technique tend to exhibit lower porosity and fewer
processing defects than do traditionally sintered ceramic materials.
⚫ In-Ceram is about three to four times stronger the earlier alumina core materials.

⚫ Modifications in In-Ceram porcelain component, lead to In-Ceram Spinell. It contains a

magnesium spinel as the major crystalline phase, which enhances the translucency of the
final restoration.
⚫ In-Ceram Zirconia, contains zirconium oxide (ZrO2), provides the highest strength.

⚫ In-ceram reported good marginal fit. However, being technique sensitive and the need
for a skilled dental technician, limited its popularity and also created poor marginal fit
sometimes.
 Pressable Ceramics

Pressable ceramics
⚫ Ceramics which are pressed under pressure and heat into a mold to make an all-ceramic
dental restoration.
⚫ Under a certain heat and pressure, a piston (Plunger) is used to force a heated ceramic
ingot through a heated tube into the designated mold. Then, the ceramic form cools and
hardens to the shape of the mold.
⚫ lost-wax technique is used to create a mould of the restoration into which ceramic is
pressed at high temperatures and pressure.
⚫ Pressable ceramics come in prefabricated ingots made of crystalline particles distributed
throughout a glassy matrix to produce a well-controlled and homogeneous material.
 Pressable Ceramics

⚫ Heat-Pressed Ceramics

⚫ Leucite Based

⚫ Heat-pressed ceramics popular in restorative dentistry since 1990s.

⚫ Restoration are waxed, invested, and pressed similar to gold casting.

⚫ Provides better marginal adaptation compared to high-strength alumina core materials.

⚫ Most heat-pressed materials contain leucite as a major reinforcing crystalline phase,

dispersed in a glassy matrix.
⚫ The crystal size varies from 3 to 10 μm, and the leucite content varies from approximately
35% to approximately 50% by volume, depending on the material.
 Pressable Ceramics

⚫ In this technique, ceramic ingots are pressed at a high temperature (≈1165°C) into a
refractory mold made by the lost-wax technique.
⚫ The ceramic ingots are available in different shades.

⚫ Two finishing techniques can be used:

1. Characterization technique (surface stain only).
2. Layering technique, involving the application of a veneering porcelain.

⚫ The two techniques lead to comparable mean flexural strength values for the resulting
porcelain composite.
 Pressable Ceramics

⚫ In the veneering technique; the CTE of the core material is usually lower than that for the
staining technique; to be compatible with the CTE of the veneering porcelain.
⚫ They were not indicated for FDP

⚫ Some current leucite-containing materials for heat-pressing:

1. IPS Empress (Ivoclar Vivadent)
2. IPS Empress CAD
3. Optimum Pressable Ceramic (OPC, Pentron Clinical)
4. Cerpress (ADS, Inc)
5. Finesse (Dentsply Prosthetics).
 Pressable Ceramics

⚫ Lithium Silicate Based

⚫ First introduced as IPS Empress II in 1998
⚫ Then in 2005 introduced as IPS e.max
⚫ Is the second generation of heat-pressed dental ceramics; where lithium disiliate is the major
crystalline phase of the core material.
⚫ A high strength of 350 Mpa.
⚫ The material is pressed at 920°C and layered with a glass containing some dispersed apatite
crystals.
⚫ It is indicated for crowns and anterior three-unit fixed dental prostheses (FDPs).
⚫ Commercially available as IPS e.max Press and IPS e.max CAD (Ivoclar)
 Pressable Ceramics

⚫ Indicated for:
1. Thin Veneers
2. Inlays & Onlays
3. Crowns in the anterior and posterior region
4. 3-unit bridges in the anterior region
5. 3-unit bridges in the premolar region up to the second premolar
6. Implant superstructures for single-tooth restorations (anterior and posterior regions)
7. Implant superstructures for 3-unit bridges up to the second premolar
8. Primary telescopic crowns
 Pressable Ceramics

⚫ Contraindicated for:
1. Posterior bridges reaching into the molar region
2. 4- and more-unit bridges
3. Inlay-retained bridges
4. Deep sub-gingival preparations
5. Patients with substantially reduced residual dentition
6. Bruxism
7. Cantilever bridge
8. Maryland bridges
9. Layer thicknesses below 1 mm
10. Preparations with sharp edges
11. Preparations that do not provide anatomical support and with irregular layering
thicknesses
Thank you 
Ceramic Inlay/Onlay
Lecturer : Ahmed Hamarsha
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