Leader in Dental Ceramics Education

www.indiandentalacademy.com
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education

INTRODUCTION.
HISTORICAL BACKGROUND.
DEFINITION.
CLASSIFICATION OF ALL CERAMIC SYSTEMS.
RECENT ADVANCES IN ALL CERAMIC SYSTEMS.
MACHINABLE CERAMICS
CEREC SYSTEM :
a) CEREC 3
b) CEREC 3D
CELAY SYSTEM
ADVANCED APPLICATIONS OF CERAMICS.
CONCLUSION
A VISION FOR FUTURE DENTAL CERAMICS

INTRODUCTION
There has been more change and development in dentistry over the past
decade than in the previous 100 years combined; and the pace is accelerating!
The 20th
century has produced the greatest advancement in ceramics and
material technology since human have been capable of conceptive thought.
In this presentation, the history , recent advances in science and technology of
all-ceramics is highlightened.

DEFINITION
The world “ceramics” is derived from the Greek “Keramikos” which means
“earthen”. A ceramic is therefore an earthy material, usually of silicate
natural and may be defined as a combination of one or more metal with a
non-metallic element, usually oxygen (Gilman, 1967). The smaller metal
atoms (or semi-metal atoms such as silicon) tucked into the spaces
between the oxygen.

During the stone age more than 10,000 years ago, ceramics
were important materials, and they have retained their importance in
human societies ever since.
Glass has its history at the beginning of time, with naturally occurring
volcanic glasses such as obsidian being fashioned into implements,
tools and jewelry as early as stone age man.
HISTORY OF DENTAL CERAMICS

Pliny is said to have suggested that man first produced glass
accidentally when a wood fire was made on a bed of silica sand.
During the Egyptian XVIII dynasty 1527- 1475 BC, hollow glass
vessels were formed around refractory cores. Alternatively,
colored rods of softened glass may have been wound around the
core before being rolled to obtain the desired shape.

By the 10th
century A.D., ceramic technology in China had
advanced to such a stage that they were able to produce: “a
ceramic so white that it was comparable only to snow, so strong
that vessels needed walls only 2-3mm thick and consequently light
could shine through it. So continuous was the internal structure
that a dish if lightly struck would ring like a bell.”

Porcelain/refractory techniques for the
construction of dentures.
IN 1774, French Apothecary Alexis Duchateau first requested the fabrication of
porcelain dentures from a Parisian porcelain manufacturer.
Then started the ERA OF CERAMICS FOR DENTISTRY………
(JPD 2004 Vol 91 Pg 136-142)

According to JADA March 1997, Vol . 128, Pg 297 -307
The five categories of all ceramic systems are :
1. Conventional ( powder – slurry) ceramics
Optec HSP, Duceram LFC
2. Castable ceramics - Dicor.
3. Machinable ceramics – Cerec Vita Blocs Mark I, Cerec Vita Blocs
Mark II, Dicor MGC, Celay.
4. Pressable ceramics- IPS Empress, Optec Pressable ceramic,
5. Infiltrated ceramics – Inceram.
CLASSIFICATION

According to
Operative Dentistry Supplement 6, 2001, 211-228
Different types of ceramics
• Silicon oxide (feldspathic) ceramics
• Aluminum oxide ceramics.
• Aluminum oxide ceramics reinforced with Zirconium oxide.
• Zirconium oxide ceramics
• Hybrid ceramics.

The strongest ceramic with white shade is yttrium
stabilized tetragonal zirconium oxide (YTZP= yttrium
stabilized tetragonal zirconia polycrystal.
Zirconium Oxide Ceramics
Operative Dentistry Supplement 6, 2001, Pg 211-228

Recent core materials and technologies :
The most recent core materials for all-ceramic FPDs are the tetragonal
Y-TZP based materials.
Y-TZP based materials were initially introduced for biomedical use in
orthopedics for total hip replacement
They were highly successful because of the material’s excellent
mechanical properties and biocompatibility.

In the early 1990s, the use of Y-TZP expanded into dentistry
as its use in endodotnic posts and implant abutments
Y-TZP is currently being evaluated as an alternative core
material for full-coverage restorations such as all-ceramic
crowns and all-ceramic FPD’s
DCNA APRIL 2004, FIXED PROSTHODONTICS

Ceramic Machining Systems
• CAD-CAM (computer-assisted
design – computer-assisted
manufacture) systems have
recently been introduced to the
dental profession.
• Development of CAD-CAM systems
for the dental profession began in
the 1970s with the efficient of Duret
in France,
• Moremann’s (Switzerland) work led
to the development of Siemens’
CEREC CAD-CAM system

• The initial investigators were working on a method called CERamic
REConstruction, hence the name CEREC.
• This system allows the dentist to make an ‘optical’ impression of the tooth
preparation wherein the surface of the prepared tooth is coated with a special
powder that has 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.
• With the aid of computer, the restoration is designed. The restoration is then
milled from a block of ceramic material using a diamond wheel and ‘custom fitted’
to the patient’s occlusion using diamond burs.

The restoration produced by the CEREC I system must be ground
and polished to develop the proper occlusal contacts and anatomy.
The new CEREC II systems also mills the occlusal surface of the
restoration, and may be used to fabricate crowns in addition to
inlays, onlays and veneers.

CELAY SYSTEM
Another innovative system that machines ceramic inlays, onlay, crowns and
bridges is the CELAY system developed by Dr. Stefan I. Eidenbenz,
The concept is there is no need for a laboratory technician.
This is a precision copy milling machine, but is not computer driven.
A light-cured composite replica of the restoration is fabricated directly in
the patient’s mouth or on a master cast. The replica is mounted on one side
of the CELAY system (the scanning side), and a ceramic block is mounted
on the milling side.
Scanning tools are used to trace the surface of the restoration while a
corresponding milling tool removes the ceramic.
The system uses a sequential milling procedure proceeding from coarse to
fine milling burs, and can mill a typical restoration in about 15-20 minutes.

Advantages
A precisely fitting ceramic restoration can be developed in one patient
session.
A ceramic restoration can be developed without the need for a lab
technician.
The restoration is developed in factory - fired high grade-porcelain.
The processing time required is very short. A complete onlay can be milled
in 12 to13 minutes.

CEREC 3 SYSTEMS
• The CEREC 3 system simplifies and accelerates the fabrication of ceramic
inlays, onlays, veneers and quarter, half, and complete crowns for anterior
and posterior teeth.
• CEREC 3 software simplifies occlusal and functional registration. Proper
occlusion is established accurately and quickly; manual adjustment is
reduced to a minimum.
• The CEREC 3 system is network and multimedia ready and, in combination
with an intra-oral color video camera or a digital radiography unit, can be
used for patient education and for user training.
• The CEREC 3 system thus is a diagnostic, restorative, training,
and documentation centre for the dental practice.

The CEREC 3 TECHNIQUE
• The CEREC 3 system has several technical improvements over
CEREC 2, including the 3 dimensional CEREC 3 intraoral
camera, manipulation of the picture, and the grinding unit.
Intraoral camera:
• The most significant factor for surveying with the CEREC 3
intraoral camera is that tooth All points of interest can be seen
from a single visual angle, i.e., the angle of preparation or
insertion.
• The CEREC 3- dimensional surveying method uses the
principle of active triangulation. Here, the camera projects a
linear pattern under triangulation angle on the preparation, and
the projected image is recorded.

In the CEREC 2 camera, the survey region, depth scale was limited to a
single value of 6.4mm.
In the CEREC 3, the problem has been solved through “ double
triangulation”. In this procedure the triangulation projection of the single
optical impression is registered with 2 separate triangulation angles. This
leads to a clear, expanded depth scale of 20mms.
Double grinding unit: the computer controlled doubled grinding unit
dispenses with the grinding wheel and uses 2 individual cutting devices.
The 2 instruments act together symmetrically in a shaping process
providing morphologically better adaptation as well as better appearance
of the occlusal design.

The CEREC 3D CAD/CAM system
• The latest incarnation of the CEREC system is the CEREC 3D,which provides
a versatile, relatively simple, user-friendly method for fabricating esthetic
restorations without involving a dental laboratory.
• It has expanded on the concepts of computer imaging by utilizing three –
dimensional viewing capacities .
• There are distinct advantages to using the CEREC 3D as compared with its
predecessors (CEREC 1, CEREC 2, and CEREC 3).
• The primary difference is the software, which requires far fewer steps than
the CEREC three and makes it easier for the dentist to proceed.

Technique
The optical impression is made. The restorations are designed on the
computer using one of the two modes, “correlation” or “Dental Data
Base”.
Correlation utilizes a preoperative optical impression of the unprepared
tooth.
Dental Data Base utilizes the software’s virtual library of tooth
morphology to create the anatomy and contours of the restoration.
From this impression a virtual model is created on the screen.
The restoration is designed and carved from a solid block of porcelain.

Features.
The 3D feature of the software allows the model to rotate 360 degrees in every
plane.
With the CEREC 3D, the margins are created automatically by the software,
reducing the chance of operator error. The software makes this a user friendly
process through an automatic margin finder.
Once the dentist is satisfied with the margin line, the software will design the
restoration and place it on the die for viewing.
Further modifications can be made using edit window which offers the dentist
six different tools; edit, drop, scale, shape, position and rotate.
Its is likely that more and more dentists will be attracted to the technology and
this software will decrease the learning curve dramatically.
(General Dentistry May-June 2004 Pg 234-235)

RECENT APPLICATIONS OF CERAMICS IN
SURGERY
Recently, the world of surgery is amazed with a sensation :
atraumatic scalpels made of ceramics.
The cutting edge cannot be made thinner than 0.7 microns
when metal is used.
Ceramics made up of zirconium dioxide nanopowder with
admixtures of aluminum and yttrium in water, can serve to form
such a material which can be used to produce the cutting edge
thickness of 0.1 - 0.2 microns.
The post operative wound heals up 2 -3 times quicker if the
ceramic scalpel is used,as the blades had dissected the tissue
without traumatizing it.
(Mendeleev University of Chemical Technology, Moscow,
14/03/2003)

Ceramics in Orthodontics
• Most recent application of ceramics in orthodontics is its use in fabrication
of orthodontic brackets.
• The development and demand for these items has been driven solely by
esthetics.
• Polycrystalline alumina is the material of choice in this application.
Advantages:
• A profitable alternative to metal brackets.
• Bonds and debonds like metal.
• Excellent control of tooth movement.
• Less friction for better treatment times.
• Lowest profile in an all-ceramic bracket.
• Maximum patient comfort.

ALL-CERAMIC POSTS AND CORES: THE
STATE OF THE ART.
• Metal posts used to restore endodontically treated teeth may shine
through all-ceramic crowns and thin gingival tissue. When non
precious alloys are used, corrosion products may lead to
discoloration.
• All-ceramic posts and cores using high toughness ceramic materials
such as alumina or zirconia ceramics can be used in combination
with all ceramic crowns to prevent this problems. They are highly
biocompatible and will almost always contribute to better light
transmission and reflectance, providing the natural translucency.
• (Quintessence Int 1999; 30: 383-392)

Implants and ceramics: Entering the New
Millennium.
• The demand for optimal single tooth implant esthetics has lead
to perhaps the most exciting development in implant abutment
design, the ceramic abutment.
• Three different designs are currently available:
CerAdapt.
CeraOne.
CeraBase.
(The Intl Journal of Oral & Maxillofacial Implants 2000; vol 15; Pg 76-94)

Conclusion
Ceramics have a great past in dentistry. Their biocompatibility and excellent
esthetics have positioned them in the high-end segment of restorative
dentistry.
The future of ceramics is even greater since they offer great potential for
improvement , especially in manufacturing technology and materials which
also means that newer compounds, precisely engineered to function will be
developed.

A VISION FOR FUTURE DENTAL CERAMICS
Although predictably stronger materials have been developed, The ultimate
restorative procedure would be the onsite production of a ceramic like enamel
substitute firmly bonded to the remaining tooth structure. If such a material
could be hardened initially it would even be possible to produce direct crowns
that are later converted into a ceramic like material. Taking this even further,
imagine that molecular – biological techniques and gene technology can be
used.

Thank you

Leader in Dental Ceramics Education

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