This document discusses various types of dental ceramics and their strengthening methods. It describes the need to strengthen ceramics due to flaws and cracks that cause failure. Methods discussed include developing residual compressive stresses through fabrication techniques, reducing firing cycles, optimal prosthesis design, ion exchange, thermal tempering, dispersion strengthening, and transformation toughening. All-ceramic systems are classified and include condensed/sintered ceramics, castable ceramics, hot isostatically pressed ceramics, glass infiltrated core ceramics, and CAD/CAM ceramics. Specific ceramic materials like zirconia and their properties are also summarized.
brief description about pressable ceramicsCONTENTS: • Introduction • Definition For Dental Ceramics • Definition For Pressable Ceramics • History • Various All Ceramic Systems • Classification • Pressable Ceramics • History • Generation Of Pressable Ceramics • Cerestore – Development Fabrication Advantage Disadvantage 2
3. IPS Empress - Materials And Composition Special Furnace Fabrication Advantage Disadvantage IPS Empress 2- INDICATION Properties Fabrication Method Advantage Disadvantage IPS Emax Press - Microstructure Composition Properties OPC 3G- Development Indication Properties 3
4. INTRODUCTION There have been significant TECHNOLOGICAL advances in the field of dental ceramics over the last 10 years which have made a corresponding increase in the number of materials available. Improvements in strength, clinical performance, and longevity have made all ceramic restorations more popular and more predictable 4
5. DEFINITION FOR DENTAL CERAMICS⁶ An inorganic compound with non metallic properties typically consisting of oxygen and one or more metallic or semi metallic elements (e.g ;Aluminium, Calcium, Lithium, Mangnesium, Potassium, Sodium, Silicon, Tin , Titanium And Zirconium)that is formulated to produce the whole or part of a ceramic based dental prosthesis 5
6. DEFINITION FOR PRESSABLE CERAMICS ⁶ • A ceramic that can be heated to a specified temperature and forced under pressure to fill a cavity in a refractory mold 6
7. HISTORY OF DENTAL CERAMICS ⁶ • 1789-first porcelain tooth material by a French dentist De Chemant • 1774- mineral paste teeth by Duchateau in England • 1808-terrometallic porcelain teeth by Italian dentist Fonzi • 1817- Planteu introduced porcelain teeth in US • 1837- Ash developed improved version of porcelain teeth 7
8. • 1903 – Dr.Charless introduced ceramic crowns in dentistry he fabricate ceramic crown using platinum foil matrix and high fusing feldspathic porcelain excellent esthetics but low flexural strength resulted in failure • 1965- dental aluminous core Porcelain by Mclean and Huges • 1984- Dicor by Adair and Grossman 8
9. 9
10. VARIOUS ALL CERAMIC SYSTEMS Aluminous core ceramics Slip cast ceramics Heat pressed ceramics Machined ceramics Machined and sintered ceramics Metal reinforced system 10
11. MICROSTRUCTURAL CLASSIFICATION⁵ Category 1: Glass-based systems (mainly silica) Category 2: Glass-based systems (mainly silica) with fillers usually crystalline (typically leucite or a different high-fusing glass) a) Low-to-moderate leucite-
There have been several changes since inception in the field of dental ceramics. Need for newer materials with improved aesthetics, flexural strength and optical properties made it necessary for introduction of advanced technology in fabrication of dental ceramics.
Dental Ceramics and Porcelain fused to metal isabel
Dental porcelain (also known as dental ceramic) is a dental material used to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers.
brief description about pressable ceramicsCONTENTS: • Introduction • Definition For Dental Ceramics • Definition For Pressable Ceramics • History • Various All Ceramic Systems • Classification • Pressable Ceramics • History • Generation Of Pressable Ceramics • Cerestore – Development Fabrication Advantage Disadvantage 2
3. IPS Empress - Materials And Composition Special Furnace Fabrication Advantage Disadvantage IPS Empress 2- INDICATION Properties Fabrication Method Advantage Disadvantage IPS Emax Press - Microstructure Composition Properties OPC 3G- Development Indication Properties 3
4. INTRODUCTION There have been significant TECHNOLOGICAL advances in the field of dental ceramics over the last 10 years which have made a corresponding increase in the number of materials available. Improvements in strength, clinical performance, and longevity have made all ceramic restorations more popular and more predictable 4
5. DEFINITION FOR DENTAL CERAMICS⁶ An inorganic compound with non metallic properties typically consisting of oxygen and one or more metallic or semi metallic elements (e.g ;Aluminium, Calcium, Lithium, Mangnesium, Potassium, Sodium, Silicon, Tin , Titanium And Zirconium)that is formulated to produce the whole or part of a ceramic based dental prosthesis 5
6. DEFINITION FOR PRESSABLE CERAMICS ⁶ • A ceramic that can be heated to a specified temperature and forced under pressure to fill a cavity in a refractory mold 6
7. HISTORY OF DENTAL CERAMICS ⁶ • 1789-first porcelain tooth material by a French dentist De Chemant • 1774- mineral paste teeth by Duchateau in England • 1808-terrometallic porcelain teeth by Italian dentist Fonzi • 1817- Planteu introduced porcelain teeth in US • 1837- Ash developed improved version of porcelain teeth 7
8. • 1903 – Dr.Charless introduced ceramic crowns in dentistry he fabricate ceramic crown using platinum foil matrix and high fusing feldspathic porcelain excellent esthetics but low flexural strength resulted in failure • 1965- dental aluminous core Porcelain by Mclean and Huges • 1984- Dicor by Adair and Grossman 8
9. 9
10. VARIOUS ALL CERAMIC SYSTEMS Aluminous core ceramics Slip cast ceramics Heat pressed ceramics Machined ceramics Machined and sintered ceramics Metal reinforced system 10
11. MICROSTRUCTURAL CLASSIFICATION⁵ Category 1: Glass-based systems (mainly silica) Category 2: Glass-based systems (mainly silica) with fillers usually crystalline (typically leucite or a different high-fusing glass) a) Low-to-moderate leucite-
There have been several changes since inception in the field of dental ceramics. Need for newer materials with improved aesthetics, flexural strength and optical properties made it necessary for introduction of advanced technology in fabrication of dental ceramics.
Dental Ceramics and Porcelain fused to metal isabel
Dental porcelain (also known as dental ceramic) is a dental material used to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers.
Introduction
CERAMICS : An inorganic compound with non-metallic prosthesis typically consisting of oxygen and one or more metallic or semi-metallic elements that is formulated to produce the whole part of a ceramic based dental prosthesis. – GPT 7.
The word Ceramic is derived from the Greek word “keramos”, which literally means ‘burnt stuff’, but which has come to mean more specifically a material produced by burning or firing.
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
Composite Resin Luting cements (2nd edition) presentation powerpoint
A type of dental cement
Used for cementation of indirect restorations & brackets
A summary of five textbooks
Porcelains used in metal ceramics /certified fixed orthodontic courses by Ind...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Introduction
CERAMICS : An inorganic compound with non-metallic prosthesis typically consisting of oxygen and one or more metallic or semi-metallic elements that is formulated to produce the whole part of a ceramic based dental prosthesis. – GPT 7.
The word Ceramic is derived from the Greek word “keramos”, which literally means ‘burnt stuff’, but which has come to mean more specifically a material produced by burning or firing.
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
Composite Resin Luting cements (2nd edition) presentation powerpoint
A type of dental cement
Used for cementation of indirect restorations & brackets
A summary of five textbooks
Porcelains used in metal ceramics /certified fixed orthodontic courses by Ind...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Dental Ceramic in Conservative Dentistry and EndodonticsSNISHAMG
Detailed description on classification of dental ceramic,composition,advantages,disadvanatages,all ceramic system,CAD-CAM,fabrication of porcelain inlay
Fundamentals, synthesis and applications of Al2O3-ZrO2 compositesTANDRA MOHANTA
When the word “Ceramic” comes to our mind, we usually associate them with plates, saucers, cups and mugs. But, the word “Ceramic” encompasses more than just the word “plates” or “saucers”. Indeed, ceramic materials are hard and inherently brittle, but this is just the tip of the iceberg. They have multifarious properties and have acquired a status of high technical importance in the field of scientific research. Ceramics are the soul of the modern day’s structural applications owing to their high mechanical and thermal stability under different challenging conditions. They exhibit remarkable properties such as high hardness, high wear resistance, high corrosion resistance, high elastic modulus, high melting point and the ability to retain high strength at elevated temperatures. Alumina (Al2O3) is one such remarkable ceramic material known for its unique optical, mechanical and electrical properties. But the brittle nature of Al2O3 limits its use in certain engineering applications. Therefore, the strength of Al2O3 and Al2O3- based ceramics can be enhanced by tailoring the microstructural design through the application of strategic techniques that may involve secondary phase particle inclusion (such as Zirconia, ZrO2)
journal cub presentation on Bps denture/biofunctional prosthetic systemNAMITHA ANAND
watch video links below for better understanding
https://www.youtube.com/watch?v=_sR2Ip5p9RE
its a series of videos 1-7 beautiful videos explaining the construction of BPS DENTURES - step by step
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
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- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
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Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
5. Griffith’s microcracks
Named after discoverer
Minute submicroscopic surface defects (scratches and
cracks) present on the glass surface
Act as stress concentration centers when subjected to
tensile stresses
Large radius at tip causes large tensile stresses at their
tips leading to crack propagation
6. Stress concentration phenomenon
Numerous minute scratches/flaws
present on the surface
Behave as sharp slits(tip narrows as
spacing between several atoms in the
materials)
Under intra oral loading tensile stress
concentrated at tip of these flaws.
Stress concentration geometry at tip of
each surface flaw.
8. As the crack propagates;
Stress concentration
is maintained at
crack tip.
Meets another
crack/pore/crystalline
particle.
Crack moves
completely through
the material
10. Stress raisers How to avoid stress raisers
Discontinuities in brittle
materials
Abrupt change in
shape/thickness in ceramic
contour
Cause stress concentration
in these areas
Restoration more prone to
fracture
Sufficient bulk
Minimum sharp angular
changes
Proper proportioning
Proper compaction
Proper drying
Firing under vacuum
Slow cooling
Glazing
12. Methods of strengthening
Development of residual
compressive stresses
Interruption of crack
propagation
Development of residual
compressive stresses
Reduced number of firing
cycles
Optimal design of
prostheses
Ion exchange
Thermal tempering
Dispersion strengthening
Transformation
toughening
13. Development of residual compressive
stresses
Fabrication of metal
ceramic/all ceramic
Sintering at high
temperature
Hot pressing a
veneering ceramic on
to the metal or core
ceramic
Process of cooling
to room
temperature
Mis match in coefficient
of thermal contraction
of adjacent materials
Metal contracts slightly
more than ceramics.
Metal pulls the
ceramics inwards-
compression of
porcelain
Bonded platinum foil
aluminous porcelain
crown technique
Swaged gold alloy
foil technique
1
2
3
14. Disadvantages
There is a limit to coefficient mismatch that can be
tolerated
Difference in coefficient of thermal contraction causes
considerable shear stress at interface
Maximum tolerable difference 0.5 M/0K to 0.7 M/0K
If more - premature failure in shear
15. Reduced number of firing cycles
Stresses during cooling
Induces crack formation and propagation
Multiple firings
Increase in thermal expansion
coefficient
Exceeds that of metal
Mismatch between porcelain and
metal
Increase in concentrations of crystalline leucite(K2O.Al2O3 .4SiO2)
High expansion crystal phase Affects coefficient of thermal contraction
Firing cycle
Chemical reactions
16. Optimal design of prostheses
• Can sustain higher tensile stresses before crack develop in areas of
tensile stress
1.Tougher and stronger ceramics
• Reduce stress concentration in the restoration where tensile
component of bending stress will develop
2.Well rounded line angles
• To avoid risk of cracking or chipping during firing
3.Avoid knife edge margins
• Reduce probability of forming microcracks and reduce depth of
microfissures produced by abrasive particles
4.Use finest grit abrasive
17. Atypical designs-leads to ceramic fracture
a four-unit metal-ceramic
cast-joined bridge with
two connector fractures
at the two cast-joined
sections in the metal
framework.
Fluorescent dye
illumination allows better
visibility of the two areas
of ceramic cracking.
18. B)Schematic of a properly
designed cast-joined
three-unit bridge
framework.
C) Five possible cross-
sectional designs for cast-
joining at the pontic.
D)Plot of force versus
strain for a solid bar.
Design 1 was the best
choice of the five designs
on the left.
19. 5.Height of connector can be increased to a
maximum of 4 mm
Tensile stresses can be reduced using greater connector
height
a connector height > 4 mm - anatomic form in the buccal
area of a posterior FPD too bulky and unesthetic
21. 6.Radius of curvature of gingival embrasure portion
of the inter proximal connector is broadened
Radius of curvature of gingival embrasure portion of the
inter proximal connector is broadened
22. Ion exchange
K+ions is 35% larger (133pm) than Na+ ion.
Large residual compressive
stresses
Ion exchange up to depth of 100
micro meter
Loses due to finishing,wear,long
term exposure to oral fluids
Concentration driven phenomenon
Equlibrium eventually established Not a complete exchange
Immersed in molten potassium salt
K+ exchanges place with Na+ Remain in place even after cooling
Sodium containing glass
Small ionic diameter(90 pm)
23.
24. Thermal tempering
Rapid cooling of surface of
material while in molten
state/quenching
Rigid
surface
+
molten
inner core
Molten core
solidifies
;shrinks and
pull rigid
outer
surface
inwards
Residual
tensile
stresses in
inner core
+
Residual
compressive
stresses
within outer
surface
25. Most widely used method of strengthening glass
In dentistry silicone oil and other special liquids are used
for quenching ceramics instead of water/air
26. Dispersion strengthening and toughening
Increase in fracture resistance
Dispersed phase interferes with crack propagation
Absorbs energy from crack Prevents its driving force propagation
Reinforced with a dispersed phase of a different material
Addition of smaller and tougher filler particles
27.
28. Examples of dispersed
crystalline phases Action depends on
Leucite
Lithium disilicate
Alumina
Magnesia alumina spinel
Zirconia
Tetra silicic flouromica
Type
Size
Volume fractions
Inter particle spacing
Their CTE as compared
to glass matrix
30. Applications
• Al2O3 particles were dispersed in a glassy porcelain matrix
Aluminous porcelain
• IPS Empress-leucite crystals
• IPS Empress2-lithia disilicate
Hot pressed glass ceramics
• Leucite reinforced
OPTEC HSP
• In Ceram-alumina,In Ceram spinel-MgAl2O3 (Magnesia alumina spinel)
Glass infiltrated core ceramics
31. Transformation toughening
A change in crystal
structure under
stress
Absorbs energy
required for
propagation of
crack
Crack shielding
and toughening of
ceramic
32. Zirconium dioxide (ZrO2),
or zirconia Should not be confused with
Biomaterial since the
1970s.
hip replacement material
in dentistry for crown and
bridge applications since
2004.
white crystalline oxide of
zirconium.
1. with cubic zirconia, ZrO2,
which is a cubic crystalline
form of zirconia used as a
diamond simulant
2. zirconium, which is a
lustrous, gray-white, strong
transition metal
3. zircon (also known as
zirkon), which is zirconium
silicate, ZrSiO4..
33. Properties of zirconia
unique mechanical and electrical properties
extremely useful in heat insulators, oxygen sensors, and
fuel cells.
nonmetal with an extremely low thermal conductivity
chemically inert and highly corrosion resistant.
tetragonal-to monoclinic phase transition results in cracks
in bulk zirconia samples and a reduction in strength and
toughness.
Under this condition pure zirconia would be useless for
dental restorative applications.
35. High-temperature tetragonal phase can be
stabilized at room temperature by
.
Doping with Mg, Ca, Sc,Y,
or Nd
Reduce the crystal size to
less than 10 nm
Yttria stabilized zirconia
ceramics is known as
ceramic steel(due to
transformation
toughening)
stabilizing oxides
1.magnesium oxide (MgO),
2.yttrium oxide (Y2O3),
3.calcium oxide (CaO),
4.cerium oxide (Ce2O3)
(highly soluble trivalent
stabilizers)
Fracture toughness of PSZ=8-10 MPa/m
Flexural strength=900MPa
Conventional ceramics =1.1-3 Mpa/m
36. SIGNIFICANT
PROPORTION OF
META STABLE
TETRAGONAL PHASE
LOCALIZED
TRANSFORMA
TION IN TO
MONOCLINIC
PHASE
VOLUME
EXPANSION
ADJACENT TO
CRACK TIPS
HIGH LOCAL
COMPRESSIVE
STRESS
AROUND
CRACK TIPS
INCREASE
LOCALISED
FRACTURE
TOUGHNES
S AND
INHIBIT
CRACK
PROPAGATI
OAN
39. Classification Based On Their Type And
Method Of Fabrication
condensed sintered
Castable glass
ceramics
Glass
ceramics
Injection
moulded glass
ceramics
Hot
isostaically
pressed
glass
ceramics
Glass
infiltrated
core ceramics
Slip cast
ceramics
Machinable
ceramics
CAD CAM
Ceramics
40. ADVANTAGES
Most life like and
esthetically pleasing
It is translucent, color
stable, brilliant
uniformly reduced and
balanced preparation
long life expectancy
fine textured restoration
increased impact strength
Biologically
acceptable(well tolerated
by the soft tissues)
Porcelain crowns
cemented on natural
abutments and those
cemented on artificial
supports have the same
incidence of fracture;
therefore, a porcelain
crown can be successfully
used after a cast- metal
post and core has been
placed on a non – vital
tooth
41. DISADVANTAGES
Excessive tooth reduction
High cost of materials and processing equipments
Wear of opposing tooth and restoration
Low repair potential
Brittleness of ceramics
Difficult intraoral polishing
Fragility when cemented with conventional cements.
42. DISADVANTAGES
Margin may not be as accurate as a cast margin and a
cement line of varying dimensions can form that tends to
wash out and stain when conventional cements are used.
Therefore resin of resin ionomer type cements are
recommended.
Cervical shadowing or “ black line” is caused by “
disruption of the light harmony between the root and
crown” of the prepared tooth and the overlying soft
tissues.To avoid this esthetic problem, the facial margin
should be placed subgingivally, but no more than half way
between the gingival crest and the depth of the sulcus.
43. INDICATIONS
Obtaining the best esthetic is the single most important
consideration.
The patient is allergic to metal.
44. CONTRA INDICATIONS
Preparation of all- ceramic crown would unavoidably cause
pulpal involvement.
The patient participates in contact sports or has a
parafunctional habit such as pipe smoking that involves heavy
contact on small areas of the dentition.
Severe bruxism/clenching/malocclusion
Extensive wear of tooth structure/restoration
Excessive bite force capability/heavy occlusal forces
Previous history of all ceramic inlay/crown fracture
Limited interocclusal distance : in cases of short clinical
crowns, deep overbite, natural tooth is not completely erupted
or with a supra erupted opposing tooth
Inability to maintain a dry field
45. Sintered/Condensed
• Optec HSP
Leucite- reinforced feldspathic porcelain
•Vitadur- N TM core
Aluminous based porcelain( Pt foil)
• Hi Ceram
Alumina based porcelain
• Mirage II
Zirconia based porcelain: Mirage II
• experimental
Magnesia based feldspathic porcelain( Experimental)
• Duceram LFC
Hydrothermal low fusing Ceramics:
46. Porcelain Jacket Crown
Types
Crowns made
entirely of
feldspathic
porcelain
Constructed on a
platinum foil matrix
which is
subsequently
removed
Porcelain Jacket Crown-
traditional
Porcelain Jacket Crown
with Aluminous core
Porcelain Jacket Crown-
with Leucite reinforced
core(Optec HSP)
Porcelain
jacketcrown
Ceramicjacketcrowns
/glassceramiccrowns
47. ALUMINOUS PORCELAIN
McLean and Hughes (1965)
Increased content of alumina crystals in the core(40-50%)
Slightly better esthetics for anterior teeth than metal
ceramic crowns
Inadequate to use for posterior teeth.
48. 40 t0 50 wt% of Al2O3
Flexural strength 131 Mpa
Platinum foil technique
ALUMINOUS CORE PORCELAIN
Finished CoresMaster
model with
dies
Platinum foil
adapted to
die,Platinum
foil functions
as matrix
It supports
porcelain
during
condensati
on and
firing
49. Unsintered CrownsDentin Ceramic
additions
Finished Crowns on
dies
Post-Cementation
Mc lean 1979 Five year failure rate 2% for anteriors 15% for posteriors
Large sintering shrinkage
Seiber et al 1981 :light reflection better than porcelain fused to metal
50. INDICATIONS CONTRAINDICATIONS
shoulder thickness of only
0.5mm possible on the
labial surface.
occlusal clearance >
0.5mm in lateral
excursions.
The preparation is conical
with a little retention.
Short teeth or where there
is too little tooth structure
to support such a
restoration.
occlusal clearance < 0.5mm.
The patient habitually grinds
or clenches the teeth.
The patient requires a
reinforced restoration, such
as a posterior FPD.
51. ADVANTAGES
withstand torque better than conventional porcelains with
fracture rates slightly less than 0.5% (MCLEAN)
Pure alumina is 6 times stronger than standard porcelains.Thus
by combining alumina core with standard porcelain, you get a
restoration which is twice the strength of porcelain alone
(ABRAMOWSKY)
Low thermal conductivity
During processing, the alumina and porcelain unite by chemical
bond thus no problem in the adhesion between the different
materials
Both materials show the same co-efficient of expansion and
contraction
Good color consistency
52. HI CERAM 1985
borrowing a technique from industrial manufacturing.
It is a system similar to aluminous core ceramic crown,
using an epoxy die, a swaged resin coping and
a conventionally applied ceramic
53. Indications Contra indications
Anterior crowns
Posterior crowns where
occlusal conditions are
favorable.
Patients who do not want a
metal core.
Patients who are allergic to
metals.
Patients who require light
reflection from tooth
through the core of the
crown for esthetic purpose.
For posterior crowns
where occlusal stress is
high.
54. OPTEC-HSP-Leucite reinforced porcelain
feldspathic porcelain with a
higher leucite crystal content
(leucite reinforced).
Its manipulation, condensation
and firing is quite similar to the
alumina reinforced porcelain
jacket crowns (using platinum
foil matrix).
Uses Inlays, onlays, veneers and
low stress crowns.
Advantages
1. more esthetic - core is less
opaque (more translucent)
compared to the aluminous
porcelain
2. Higher strength
3. No need of special laboratory
equipment
Disadvantages
1. Fit is not as good as metal
ceramic crowns
2. Potential marginal inaccuracy.
3. Not strong enough for
posterior use.
55. Duceram LFC/Hydrothermal low fusing
ceramics
Advantages
It’s a low fusing
hydrothermal ceramic
consists of an amorphous
glass containing hydroxyl (-
OH) ions.
was developed in mid-1980
first time marketed in 1989
use in all ceramic prostheses,
ceramic/ metal-ceramic inlay,
and partial crowns.
greater density
higher flexural strength
greater fracture resistance
lower abrasion than
feldspathic porcelain.
Being highly polishable
they do not require
glazing
56. • The base layer containing Leucite
• condensed on a refractory die using conventional
powder slurry technique and sintered at 930 0C.
Duracem MC
(Duceram Metal
Ceramic )
• The veneering layer
• Duceram LFC is condensed with this base layer
and sintered at 660oC
Duceram LFC
(Duceram Low
Fusing Ceramic)
58. Glass ceramics
TYPES OF GLASS
CERAMICS
MacCulloch in 1968.
used a continuous glass-
molding process to
produce denture teeth.
suggested that it should be
possible to fabricate
crowns and inlays by
centrifugal casting of
molten glass.
CASTABLE
CERAMICS
MACHINABLE
CERAMICS
HOT
ISOSTATIC
ALLY
PRESSED
CERAMICS
59. GLASS CERAMICS
Promotes increased strength and toughness
Loss of glassy structure by crystallisation of glass
when an intraoral force was applied
Crystalline particles, needles, or plates
interrupt the propagation of cracks in the
material
Material is formed into the desired shape as a glass
Subjected to heat treatment to induce partial devitrification
60. CASTABLE GLASS CERAMICS
Supplied as
Properties are more
closer to glass
Only porcelain restoration
made by centrifugal
casting technique
Unique ceramming
process-enhance growth
of mica crystals
Glass ingots
Pre crystallised form-
Dicor MGC(as machinable
blanks for CAD CAM)
Uses
Inlays
Onlays
Veneers
Low stress crowns
61. Dicor
The first commercially available castable ceramic material
for dental use
Developed by Corning GlassWorks
Marketed by Dentsply International
Adair and Grossman
62. Fabrication of DICOR crown
Pattern constructed in wax
Invested in refractory material like a
regular cast metal crown
After buring out wax,nuggets of Dicor
glass are melted and cast into the
mould in a centrifugal casting machine
63. Glass casting is carefully removed from the
investment by sandblasting and the sprues are
gently cut away
The glass was then covered by a protective
“embedment” material and subjected to a heat
treatment(ceramming)
microscopic platelike crystals of tetrasilicic
fluormica to grow within the glass matrix.This
crystal nucleation and growth process is called
ceramming
Once the glass was cerammed, it was fit on the
prepared dies, ground as necessary, and coated with
veneering porcelain and a stain and glaze layer to
match the shape and appearance of adjacent teeth
64. Advantages
Ease of fabrication
Good esthetics(greater
translucency and
chameleon effect)
Improved strength and
fracture toughness
Good marginal fit
Very low processing
shrinkage
Low abrasion of opposing
teeth
Disadvantages
Inadequate strength for
posterior use
Internal characteristaion
not possible
Has to be stained
externally to improve
esthetics
65. CHAMELEON EFFECT
Dicor glass-ceramic was capable of producing remarkably good
esthetics, perhaps because of the “chameleon” effect, in which
part of the color of the restoration was picked up from the
adjacent teeth as well as from the tinted cements used for
luting the restorations.
The transparent crystals scatter the incoming light.The light
and also its color, is disbursed as if the light is bouncing off a
large number of small mirrors that reflect the light and spread
it over the entire glass-ceramic.
66. Dicor
characterized by the controlled crystallization (termed
ceramming) of a glass through the presence of one or
more nucleating agents.
55% by volume of tetrasilicic fluormica
(KMg2.5Si4O10F2)
was derived from the quaternary ceramic system, K2O-
MgF2MgO-SiO2.
low flexural strength (110 to 172 MPa)
low fracture toughness (1.6 to 2.1 MPa•m1/2)
67. Difference between Dicor and Dicor MGC.
Dicor Dicor MGC
55%vol of tetrasilicic
fluoramica crystals.
70% vol of tetrasilicic
flouramica crystals which are
2 µm in diameter
Crystallization done by the
technician.
Higher quality product that is
crystallized by the
manufacturer and provided
as cadcam blanks or ingots.
Mechanical properties
similar.
Less translucent than Dicor.
Only one shade Dark and light shades
available
Flexural strength is more
.
68. Hydroxyapatite based castable glass
ceramics: Cerapearl.
Sumiya Hobo and Kyocera Bioceram group of Kyoto
City, Japan .
Castable glass ceramic :CaO- P205- MgO-Si O2
Cerapearl
Oxyapatite
Hydroxyapatite
Moisture
Enamel
69. Melts at 14600C and flows like a melting glass.
CTE small enough to obtain accurate castings.
The cast material has an amorphous microstructure when
reheated at 8700C forms crystalline HA.
Biocompatible: Crystalline structure similar to enamel.
Enamel: Regular arrangement.
Cerapearl: Irregular arrangement.
Hence same crystal components but superior mechanical
strength.
Modulus of rupture :150 Mpa.
Enamel
Cerapearl
Properties of Cerapearl
70. Crowns thicker than metal ceramic because of poor flexural characteristics.
Tooth
preparation
2mm: occlusal reduction
1.5 mm: axial reduction.
1.2 mm on the margin.
Heavy chamfer or shoulder finish line.
All sharp edges should be rounded.
Procedure For Cerapearl
Waxing
A full arch impression is made.
Working cast fabricated with Type IV stone.
Dowel pins are employed.
Die spacer of 25μm is applied on the die
except within 1 mm of the finish line
Wax pattern is fabricated
71. Casting
Wax sprue 2.5 mm in diameter and 35 mm long. is
attached to the thick portion of the wax pattern. Other
end :orifice of the ceramic crucible.
A spl. phosphate bonded high heat investment
Investment exhibits the same CTE as Cerapearl’s casting
shrinkage( 0.53%).
The sprued wax pattern is located inside preformed
silicone form used for fabrication of ringless investment
mold and investment is poured.
Burnout procedure for cerapearl
Temperature less than 1000C for 30 min.
Temperature is raised to 5000C ,next 30 min.
Temperature is held at 8000C for 30 min.
Electric oven
Ringless investment mold with ceramic
crucible on the top
72. Casting of cerapearl Investment mold is transferred to
a specially designed casting machine.
8-10 g of raw Cerapearl is placed
in the ceramic crucible,
Melted under vacuum at 14600C
and cast into the mold.
Crystallization of Cerapearl.
Started at 7500C ,maintained for 15 min.
Temperature is then raised 500C per min until it
reaches 8700C and then held for one hour.
The apatite crystals would have occurred during the
process.
73. Cerastain by Bioceram
Trial insertion:Cerapearl.
Investment mold is removed from the oven and
cooled to room temperature.
Air abrading with 20 μ alumina oxide of the
casting.
The sprue is cut and polishing is done.
Staining and glazing:
Cerapearl is very white compared to enamel
Requires application of an external stain.
74. Slip cast ceramics/glass infiltrated core
ceramics
• ALUMINA
In Ceram
• MAGNESIA ALUMINA SPINELL
In Ceram Spinell(ICS)
• ZIRCONIA
In Ceram Zirconia
In Ceram 2000
75. GLASS INFILTRATED CERAMICS
A process used to form
green ceramic shape by
applying a slurry of
ceramic particles and
water or a special liquid
to a porous substrate
Such as a die material,
there by allowing
capillary action to
remove water and
densify the mass of
deposited particles
76. GLASS INFILTRATED CORE
CERAMICS/SLIP CAST CERAMICS
3 GLASS INFILTRATED
CORE CERAMIC SYSTEMS Minimize sintering
shrinkage
Ensure adequate fit
Each of these partially
sintered ceramics can be
infiltrated with a
lanthanum glass without
any significant dimensional
change.
Magnesia-
alumina
spinel
(MgAl2O4)
Zirconia-
alumina core.
Partially
sintered
alumina
77. • 85%alumina by volume
• Mean flexural strength-600MPa
VITA In-
Ceram
Alumina
• magnesia alumina spinel (MgAl2O4)
• More translucent
• Mean strength-350MPa
In-Ceram
Spinell
(ICS)
• 62% alumina, 20% zirconia, and 18%
infiltrated glass
• Mean flexural strength-620MPa
In-Ceram
Zirconia
78. Glass infiltrated ceramics
Uses
In addition to the usual inlays,
onlays, veneers and low
stress(anterior and posterior)
crowns, this material can be
used to construct low stress
anterior bridges. Because of its
occasional tendency to fracture
when used for bridge
construction its use should be
carefully selected
For people allergic to metal
based bridges
Where esthetics is absolutely
critical
79. Infiltrated with lanthanum based glass
Lanthanum glass melts Flows into pores
Forms inter penetrating
network
Sintered (11200 C for 10 hrs or more)
Porous core
Slip applied on to the gypsum die with brush-ceramic core
Water is removed by capillary action of porous
gypsum
Packed rigid network of ceramic particles
Powder particles coated with a polymer – even suspension
pH of water adjusted to create a charge on ceramic particles
80. Fabrication
Two dies are required
1. In stone
2. In refractory die material
Working model
Duplication
In-Ceram refractory
dies
81. Preparing the slips- A slurry of alumina is prepared and
deposited on the refractory die using the slip cast
method (the water from the slurry is absorbed by the
porous die leaving a layer of alumina on the surface).The
process is continued until a alumina coping of sufficient
thickness is obtained.
Prepared slip should be
smooth and homogenous
82. vita inceramat
The fragile slip cast alumina coping is dried
at 120°C for 2 hours.
The coping is sintered (Inceramat
furnace ) for 10 hrs at11200 C
After sintering the coping are tested
for cracks using a special dye
83. A slurry of glass material
is applied on to the
sintered alumina coping
and fired for 3 to 5 hours
at 1120°C.
The glass fuses and
infiltrates into the porous
alumina coping through
capillary action
84. The excess glass forms a glassy layer on the surface
which is trimmed off using special diamond burs.
The coping is now ready for the rest of the build up
using dentin and enamel veneering material (Vita
VM7)
Vaccumat 4000 Premium
85. Application of body
and incisal porcelain
Postoperative veiw of
In-Ceram crowns
Finished In-
Ceram copings
(Air abraded)
Finished crowns
Preoperative veiw
Probster et al : Strength of In-Ceram > IPS Empress < PFM
86. ADVANTAGES DISADVANTAGES
Good fit and marginal
adaptation
Good strength
Giordono 1995 : Al2O3
Core glass infiltrated
Ceramic > Strength than
Hi-Ceram, Di-Cor &
Feldspathic Porcelain
Strong enough for
posterior single crowns
and anterior FPD use
Comparatively less
esthetic because of the
opacity of the alumina
core.
Quite tedious to fabricate.
Not all the bridges were
successful, a few of them
did fracture occasionally.
87. Pressable/Hot Isostatically
Pressed/Injection Moulded Ceramics
• IvoclarVivadent
IPS Empress
• Leach and Dillon
Cerpress SL Pressable Ceramic System
• DENSTSPLY Ceramco
Finesse All Ceramic System
• IvoclarVivadent
IPS Empress11
• Pentron laboratory technologies
OptecOPC 3G
Contain
35% vol of
Leucite
crystals
Contain
65-70%
vol lithia
disilicate
90. The most well-known
leucite-based products
IPS Empress (Ivoclar
Vivadent)
Cerpress SL Pressable
Ceramic System (Leach
and Dillon)
Finesse All-Ceramic
System (DENTSPLY
Ceramco).
The glassmatrix layering
ceramic for these core
materials also contains leucite.
low flexural strength (up to
112 MPa) and fracture
toughness (0.9 to 1.3
MPa•m1/2) but twice that of
feldspathic ceramic
Higher porosity (9%)
not recommended for molar
crowns or bridges.
First generation pressable ceramics
91. Second generation pressable ceramics
contain approximately
65% to 70% by volume of
lithia disilicate
(Li2O•2SiO2) as the
principal crystal phase.
narrow sintering range-
processing of ceramic
prostheses very technique
sensitive
IPS Empress 2 (Ivoclar
Vivadent) and Optec OPC
3G (Pentron Laboratory
Technologies)
Initially lithium
metasilicate,cristobalite
forms
Final structure- highly
interlocked lithium
disilicate crystals(0.5µ in
length and 0.8µ in
diameter)
92. Second generation pressable ceramics
Advantages
Improved strength ( Inter
locked micro structure
and layered crystals)
crack propagation is
difficult in a direction
perpendicular to the
crystals alignment
Flexural strength twice
that of 1st generation.
mean flexural strength is
approximately 350 MPa
compared with the 112-MPa
strength of leucite-based
glass-ceramics.
This strength and a fracture
toughness of 3.3 MPa·m1/2
for lithia disilicate–based
glass-ceramics are generally
sufficient for
1.most anterior and posterior
crowns
2.anterior three unit bridges
95. Reasons for improved flexural strength
Additional re crystallisation during firing
Additional firings Improved flexural strength
Contributes to crack deflection
Prevent crack propagation Improved mechanical properties
Difference in coefficient of thermal expansion of glassy matrix and crystals
Tangential compressive stresses develop around leucite/lithium disilicate crystals
96. Fabrication of Pressable ceramics
Technique similar to
injection moulding
Since from a single ingot –
mono chromatic
Can be cast as coping and
layered with veneering
ceramics
Used for inlays, onlays,
single crowns and veneers
Glass ceramic
ingot is heated
Allowed to flow
under pressure into
mould using lost
wax technique
Contoured, stained,
and glazed for final
finish
97. FABRICATION
The wax patterns of the restoration are invested in
refractory material and heated to 8500 C in a furnace to
burn off the wax and to create mould space
98. Burn out 8500 C
It is then transferred to the
pressing furnace
99. Ceramic ingot &an
Alumina plunger is
inserted in to the
sprue
Pressing temperature
1075-11800 C-IPS
Empress
9200 C-IPS Empress II
Under air pressure-1500
psi
100. Core of restoration is retrieved from the flask
Compatible veneering porcelains are added to core to
build up final restoration
101. Property IPS Empress IPS Empress II
Core ceramic Glass ceramic with 35% vol of
leucite crystals.
Glass ceramic with 70%
vol of lithium disilicate
crystals.Lithium
orthophosphate in
much lower
concentrations.
Veneering
ceramic
Also contain leucite crystals in
glass matrix
Contains apatite
crystals which causes
light scattering similar to
tooth structure.
Processing
temperature
11800C 9200C
103. Heat pressed(hot isostatically
pressed)ceramics /injection moulded
ceramics
Advantages Disadvantages
Better fit- because of
lower firing shrinkage
Better esthetics-absence
of metal or an opaque
core
Need for costly
equipment
Potential fracture of
posterior areas
Edward B Goldin 2005 compared leucite IPS Empress with PFM
Mean marginal discrepancy 94 + 41 PFM
81 +25 IPS
105. Essentials of a CAD CAM System
• Virtual impression
Scanner/digitizer
• Virtual design (CAD)
Computer
• Produces the restoration or framework
Milling station
• Raw material for restoration
Ceramic blanks
• Post sintering,ceramming
Furnace
106. Schematic representation of CAD CAM
production
Tooth preparation
Conventional impression and die
fabrication
Wax pattern
Restoration or
framework
design(CAD)
Restoration or framework
milling(CAM)
Furthur processing-simple glazing
and staining to post sintering and
build up with veneering ceramics
Contact probes
/ optical
scanning
107. SCANNER OR DIGITIZER
CONTACT PROBES
Physically contacts the die
as it moves along its
surface while transmitting
the information to the
computer
Eg.Procera Forte contact
scanner
108. Scanners
Intra oral hand held wands Laboratory scanners
Chair side scanners
Reflects light(visible
light,laser or LED)
Captures it with a camera
Create an optical
impression of prepared
tooth and adjacent
structures
Stitch multiple images to a
3D image in computer
Larger scanners
Scan the cast or die
1. use a camera to capture
multiple images
Eg.white light optical scanner
2.Two cameras to capture the
object from multiple
angles using white light
Eg.Kavo Everest
3.Laser planes projected in a
grid pattern
110. Most recent versions of digital impression
softwares
3M ESPE Lava Chairside
Oral Scanner C.O.S
3M ESPE CEREC AC
Sirona Dental Systems
LLC;E4D Dentist
D4DTechnologies
iTero
Cadent,Inc.
Allow complete 3D
visualisation of the
projected restoration with
virtual seating capabilities
Various surfaces of the
virtual restoration can be
modified in all three
dimensions prior to
machining
111. Lava Chairside Oral Scanner
C.O.SiTero
Parallel
confocal
imaging-100000
point maps at
300 focal
depths spaced
50µ apart
Based on active optical wavefront
sampling
3 sensors collect video data from
different perspectives
20 3D datas per second
24 million datapoints per arch
112. 3M ESPE CEREC AC
High speed swept laser beam
combined with a camera
Series of 3D SCANS
Principle of LASER
triangulation
CEREC Bluecam-blue light
emitting diode and camera
system
Active triangulation to
create images of the tooth
surface
113. Computer/CAD Process
Restoration/core is designed based on software
Can automatically detect finish line
Some use a library of tooth shapes stored in computer
and suggest the proposed restoration
A recording of bite registration is also added to the data
Combined information+3D optical impression-establishes
approximate zone in which the new restroration can
exist
Can modify and correct the design if required
114. MILLING STATION
Signals from computer - milling tool which shapes the
ceramic block (according to the computer generated
designs)
Performed by a diamond or carbide milling tool
Cerec station-2 diamond bur to grind internal and
external surface simultaneously
Other machines-single tool moving along multiple axis(2-
5 axis)
Everest or kavo engine-5 axis milling station;Can mill both
ceramic and titanium
115. Can be
produced by
by chair-side
milling units
industrial
milling
processes
processing multiple jobs with a
high level of accuracy and
reproducibility.
very expensive( with typical
costs in excess of several
hundred thousand USD for
industrial CAD CAMS)
limited in their
processing speed and
their ability to process
large cases.
116. CERAMIC BLANKS
• Vitablocs Mark II (Vita)
Feldspathic porcelain blanks
• DIcor MGC,(tetrasilicis flouromica)Pro Cad,Everest G(Kavo)(leucite),IPS emax
CAD(Kavo)(lithia disilicate)
Glass ceramic blanks
• Alumina,(Vita InCeram Alumina)spinell,(Vita InCeram Spinell),zirconia(Vita In Ceram Zircona)
Glass infiltrated blanks
• Alumina (Vita In Ceram AL),
• Yttria stabilized zirconia (Vita In CeramYZ)
Pre sintered blanks
• Yttria stabilized zirconia (Everest ZH blanks)
Sintered blanks
117. Machinable ceramicsFromCADCAMceramic
blanks
Feldspathic porcelain-
Vitablocs Mark II
Lithia disilicate glass
ceramic-IPS e max
CAD,Kavo
Glass infiltrated
Partially sintered
zirconia-Vita In
CeramYZ
Sintered zirconia-
Everest ZH
FromCopymilledceramic
blanks
Alumina blocks-Celay
In Ceram
MgAl2O3 blocks-In
Ceram spinell
118.
119. • Can be milled to full contour
Feldspathic porcelain blanks
• Can be milled into full contour
Leucite reinforced
• Usually machined as cores or FPD substructures
• Subsequent glass infiltration,veneering,and glazing
Glass infiltrated blanks
• Machined in intermediate crystalline state-material shows characteristic
blue shade
• In this stage easier to shape and try in mouth
• Followed by simple, quick crystallization process-30 mnts
Lithium disilicate
120. MACHINABLE ALL CERAMIC MATERIALS
HARD MACHINING
SOFT MACHINING
FOLLOWING SINTERING
Machined in
fully sintered
state
Restoration is
machined
directly to final
size
In partially sintered state
Later fully sintered
Requires milling of an enlarged restoration
to compensate for sintering shrinkage
Used for alumina,spinell,zirconia(difficult to
machine in fully sintered state) Copings are
furthur glass infiltrated
Microstructure similar to that of slip cast
ceramics
Final marginal accuracy within 50µ
121. Hard machining
Machining of restoration from ceramic blocks by a computer controlled milling machine
Takes only few minutes
Bond to tooth preparation with resin
cements
Design restoration with aid of computer
Tooth preparation
Optical scanning Computerisation of image
122. Presintered Zirconia Sintered Zirconia
Most zirconia frameworks
are fabricated by machining a
porous or partially fired
block
Used as cores for crowns
and FPDs
Softer and easier to mill
Milled to larger size(20%)
Shaped by carbide burs
Post sintering
Sintering time-6-7.5 hours
Sintering temperature-1350-
15300 C
No need of post sintering
No shrinkage is expected
Takes more time(2hrs for a
single crown) and wear of
milling tool(extreme
hardness)
Shaped by diamond disks
and burs
Core construction for
crowns and long span
anterior and posterior FPDS
129. Procedural sequence for producing
ceramic prostheses by a CAD-CAM
system using partially sintered blanks:
Set the blank in
milling machine
Set the
enlargement
factor
Insert appropriate
milling/machining
tool
Remove the
framework and
residual blank
Cut the
framework from
blank using
diamond disk
Clean the partially
sintered
framework
completely
130. Dry the framework
completely
Place the
framework in the
isothermal hot zone
of the sintering
furnace
Set the thermal
processing
conditions according
to sintering
instructions
Sinter the
framework to
achieve optimal
density
After cooling
remove framework
Inspect for surface
and sub surface flaws
using fibre optic
trans illumination
131. Evaluate the
framework for
adequacy of wall
thickness,ease of
seating,and marginal
fit
Use water cooled
diamond tool to
perform minor
adjustment
corrections
Rinse the
framework
thouroughly with
water and dry it
completely
Depanding on the
zirconia product
framework used
with or without
veneering ceramic
Transitional liner
prior to application
of veneering
ceramic
132. COPY MILLED (CAM) SYSTEMS
Wax pattern of restoration is scanned
Replica is milled out of the ceramic blank
Celay
• Mikrona
Technologies,
Spreitenbach,
Switzerland
Cercon
• Degudent,
• Dentsply
• Has both
CAD CAM
and copy
milling system
Ceramill system
134. CELAY SYSTEMS
Uses copy milling technique
Resin pattern fabricated directly on master die and
pattern is used for milling porcelain restorations
Jacot et al 1998 : in ceram blanks in celay system.
Sorenson 1994 : marginal fit of CELAY > CEREC
Inlay pattern mounted
(copy side)
Copy milling pattern out
of ceramic material
(milling side)
135. It is an innovative system developed by Dr.Stefan I.
Eidenbenz at the university of Zurich in 1994
It is a high precision, manually operated copy milling
machine and the fabrication principle is the same as for
'Key' duplication.
136. prefabricated pattern of the
designed restoration made
from a blue resin-based
composite (Celay-Tech, ESPE,
Seefeld-Oberbay, Germany).
The resin pattern can be
produced directly on
prepared teeth or indirectly on
dies made from impressions
137. As the tracing tool passes over
the pattern, a milling machine
duplicates these movements as it
grinds a copy of the pattern from
a block of Alumina or other
ceramic material
138. Advantages Disadvantages
Precisely fitting ceramic
restorations can be
developed without a lab
technician in high grade
factory fired porcelain, in a
very short time in one
session.
The grains are finer than
conventional In-Ceram,
therefore the strength is
more than conventional.
the accuracy of the copy-
milled crowns is
dependent on the care,
time, and the profile
tracing ability of the
technician, the marginal
quality of crowns made
from the copy-milling
technique is likely to be
inferior to that of copings
made from the hot
pressing method.
139. 3.CERCON
It is commonly called as a CAM system as it does not
have a CAD component.
This system scans the wax pattern and mills a zirconia
bridge coping from presintered zirconia blanks, which is
sintered at 1,3500C for 6-8 hrs.
Veneering is done later on to provide esthetic contour.
Marginal adaptation for the cercon crowns and fixed
partial dentures was reported 31.3 μm and 29.3 μm
respectively.
140.
141. Ceramill system
Based on pantograph type of copy milling
‘puts material back in the hands of technician,
To create a zirconia coping,user applies light cure resin
over a traditional die
Attaches resin pattern into a plastic plate
Inserts it into milling unit side by side withYtZP zirconia
blank
142. Two conjoined arms of Ceramill system
• User manually traces
the resin build up
with probe tip
Holds the
probe tip
• Simultaneously mills a
duplicate coping out
of the zirconia block
Milling
handpiece
145. 1.CEREC(Chair Side Economic
Reconstruction of Esthetic Ceramic)
CEREC 1
• 1980-s
CEREC II
• 1996
CEREC III
• 2000
Optical scanner is used to scan
the preparation or the impression
and a 3D image is formed on the
monitor.There is a milling unit to
prepare the restoration
Can record multiple images within a
few seconds, which enables the
clinician to prepare multiple teeth in
same quadrant thereby creating a
virtual cast for that quadrant
146. Cerec System consists of :
A 3-D video camera
(scan head)
An electronic image
processor (video
processor) with memory
unit (contour memory)
A digital processor
(computer) connected to,
A miniature milling
machine (3-axis machine)
147. Materials used with CEREC
Dicor MGC (Machinable Glass Ceramic)(Dentsply)-mica
based machinable glass ceramic containing 70% vol of
crystalline phase
Vita Mark II (Vident):contain sanidine (KALSi3O8) as a
major crystalline phase within a glassy matrix.
148. ProCad (Ivoclar):Like Ivoclar's popular Empress™
material, ProCAD is reinforced with tiny leucite particles,
and has been referred to as: "Empress on a stick".
Vita IN-Ceram Blanks (Vita Zhanfabrik):
IN-Ceram Spinell.
IN-Ceram Alumina.
IN-Ceram Zirconia
152. Clinical shortcoming of Cerec 1 system :
Although the CEREC system generated all internal and
external aspects of the restoration, the occlusal anatomy
had to be developed by the clinician using a flame-shaped,
fine-particle diamond instrument and conventional
porcelain polishing procedures were required to finalize
the restoration.
Inaccuracy of fit or large interfacial gaps.
Clinical fracture related to insufficient depth of
preparation.
Relatively poor esthetics due to the uniform colour and
lack of characterization in the materials used.
153. Cerec 2
The changes include :
Enlargement of the grinding unit from 3 axis to 6 axis
Upgrading of the software with more sophisticated technology
which allows machining of the occlusal surfaces for the
occlusion and the complex machining of the floor parts.
Other technical innovations of Cerec 2 compared to Cerec 1:
The improved Cerec 2 camera : new design, easy to handle, a
detachable cover (asepsis/sterilization), reduction in the pixel
size/picture element to improve accuracy and reduce errors.
154. Data representation in the image memory and processing
increased by 8 times, while the computing capacity is 6
times more efficient.
Magnification factor increased from x8 to x12 for
improved accuracy during measurements.
Improved in rigidity and grinding precision by 24 times.
Improved accuracy of fit
155. Cerec 3
Software still easy and user friendly which uses windows
as operating system.
Two compatible cameras available- SIROCAM 2 /
SIDEXIS.
Precise restorations.
Extra-oral and intra-oral measuring.
Rapid production.
The imaging unit and the milling unit can be linked via
cable, IRD port, networked.
Supported with online help and design.
156. Cerec-3 that can design well-fitting inlays, onlays, crowns, veneers etc.,
in a single visit.
157. Advantages of CEREC System
One or two appointments.
Optical impression, max time required is 5 sec.
Wear hardness similar to enamel.
Less fracture due to single homogenous block.
Excellent polish.
Improved esthetics.
Time saving.
Good occlusal morphology in relation to antagonist.
158.
159. INDIRECT CAD - CAM
System that consists of several modules with at least, two
distinctive CAD & CAM stations
The optical impression is taken in the dental office, where
CAD is done; data are transmitted to CAM station for
restoration fabrication.
The optical impression is taken in the dental office;
collected information is then transmitted to a central
station, where CAD & CAM modules operate.
160. Because of the overall dimensions and the cost of the
indirect CAD – CAM devices, they are usually not located
in the dental office, but more likely in a central laboratory
where data is collected from different treatment places.
E.g.
Duret system.
Procera system (Noble Bio-Care).
Cicero system(Elephant Industries).
President system (DCS Dental).
CEREC SCAN & CEREC InLAB (Sirona Dental company)
161. CEREC SCAN
CEREC SCAN (inclusive of both scanning and milling
device)with lap top(imaging device).
162. Tooth preparation.
Conventional impressions.
Die preparation.
Controlled by one of the practice pc’s.
Works upon CEREC 3 software.
Intra oral scanning device is not present.
168. 2. DCS Precident
Consists of a laser Scanner called as Preciscan and a
multitool milling center called Precimill CAM.
The DCS software automatically provides suggestions for
connector sizes and pontic forms.
It can scan upto 14 dies simultaneously and mill 30
frameworks in one fully automated operation.
It can also mill titanium and fully dense sintered zirconia.
An in vitro study showed that marginal discrepancies of
alumina and zirconia based posterior fixed partial denture
machined by the DCS system was between 60 μm to
70μm
169. 3. Procera All Ceram System
introduced in 1994.
first system which provides outsourced fabrication using a
network connection.
According to research data average marginal gap for
Procera all Ceram restoration ranges from 54 μm to 64
μm.
171. Procera All-Ceram
Developed by Dr. Matts Andersson for Nobel Biocare
embraces the concept of computer assisted design and
computer assisted machining .
The technician can design a coping for a full crown
restoration controlling the thickness, emergence profile,
and precision of fit.
The design data can be forwarded to the manufacturing
facility and the coping produced in various materials.
The Procera AllCeram Crown involves a densely sintered
high-purity alumina core combined with a low fusing
veneering porcelain fabricated by the pressed powder
technology.
172. Advantages:
The finished crown has a translucence very similar to the
natural tooth.
Aluminum oxide is a highly biocompatible material,
comparable to titanium.
The coping is made of dense-sintered aluminum oxide to
maximize strength.
The Procera technique guarantees high precision for
optimal fit.
173. A technician using the special Procera design station
scans the die and designs the coping to be fabricated.This
station consists of a computer, a modem and the Procera
scanner
Once positioned on the scanner, a probe lightly touches
the die as it is rotated.A 3D map is produced from this
"tactile scan" that consists of approximately 50,000 data
points from around the die.
174.
175. After the master die is
scanned all the 3-D images
are transferred to the
processing center through
an internet link
an enlarged die is milled
by a computer controlled
milling machines.
The coping is sent to the
lab for veneering of
porcelain
Contact scanner
Shape on computer screen
176. 4. CICERO system (computer integrated
crown Reconstruction)
it was introduced by Denison et al in 1999,
it includes optical scanning, metal and Ceramic sintering
and computer assisted milling to obtain restoration.
The aim of CICERO is mass production of ceramic
restorations at one integrated site.
It includes rapid custom fabrication of high strength
alumina coping and also partially finished crowns to be
delivered to dental laboratories where porcelain layering
or finishing can be done.
177. 5.Lava system
introduced in 2002
mainly used for fabricating zirconia framework for the all
ceramic restorations.
Yttria stabilized tetragonal zirconia poly crystals (Y-TZP)
are used in this system are better than the conventional
ceramics as they have greater fracture resistance.
uses a laser optical system to transfer and digitize
information received from the preparation.
The Lava CAD software suggests a pontic automatically
according to the margin.
178.
179.
180. Cementing of ceramic restorations
-Resin bonding agents
Increase the retention of all-ceramic crowns and bridges.
High bond strength
Esthetics at margins is better
Improved translucence
Increase the fracture resistance and survivability of
ceramic restorations
Reduces water access to the inner ceramic surface
Etching blunts the tips of microcracks within the
ceramic,thereby inhibiting crack propagation
181. Bonding of cement to porcelain can be
improved by
• Create minute irregularities on the inner surface-
help the cement to retain better
• Clean in distilled water in an ultrasonic bath-10
minutes
1.Sandblasting
• Done with hydroflourous acid or ammonium
biflouride
• 2minutes
2.Chemical
etching
• Functions as coupling agent(difunctional
molecule)
• for silica based porcelains
3.Use of silane
primers
182. SILANE PRIMERS/COUPLING AGENTS
Contain one or more silicon
atoms
3-methacryloxypropyl
trimethoxysilane
Silane primers provide
covalent bonds that
promote adhesion at the
interface between polymers
and hydrolytically stable
silica based substrates,
assuming that the substrate
is free of contaminants
The bonding stage of silane
primer or adhesive to a
silicabased ceramic.
183. Silane as a di functional molecule
Methacrylate
group
• Capable of co
polymerisation with
methacrylate based
adhesives and resins
Methoxy
group(–
OCH3)
• that are hydrolyzed to
silanols (Si–OH) for
bonding to inorganics
such as silica-based
ceramics or metal oxide
substrates through the
formation of siloxane (–
Si–O–Si–) bonds.
184. Reaction of silanes with slica based
ceramics-4 stages
• Of methoxy groups
Hydrolysis
• Of oligomers
Condensation
• the oligomers then hydrogen bond with OH groups of the substrate.
Hydrogen bonding
• during curing, covalent links are formed with the substrate with
simultaneous loss of water
Bond formation
185. Factors affecting abrasiveness of dental
ceramics
Properties of the crystal phase particles and the glass
matrix (if present)
hardness
tensile strength
fracture toughness
fatigue resistance
particle-glass bonding
particle-glass interface
integrity
chemical durability
exposure frequency to
corrosive chemical agents
acidulated phosphate fluoride,
carbonated beverages
abrasiveness of foods,
residual stress
subsurface quality (voids or
other imperfections)
magnitude and orientation
of applied forces
chewing patterns
bruxing frequency
contact area
lubrication by saliva
duration of exposure to
abrasive particles.
186. Minimizing excessive wear of enamel
(1) ensure cuspid-guided disocclusion
(2) eliminate occlusal prematurities
(3) use metal in functional bruxing areas
(4) if occlusion is in ceramic, use ultralow-fusing ceramics
(5) polish functional ceramic surfaces
(6) re polish ceramic surfaces periodically
(7) readjust occlusion periodically if needed.
187. CHEMICAL ATTACK OF GLASS-PHASE CERAMICS
BY ACIDULATED PHOSPHATE FLUORIDE
When glazed feldspathic porcelain is exposed to 1.23%
APF or by 8% stannous fluoride, a surface roughness is
produced within 4 min.
a 30-min exposure to 1.23% APF gel appears to
preferentially attack the glass phase (areas with white
precipitate particles) of a gingival (body) porcelain.
ROUGHNESS STAINING
PLAQUE
ACCUMULATION
BREAKDOWN OF
THE STRUCTURE
188. CHEMICAL ATTACK OF GLASS-PHASE
CERAMICS BY ACIDULATED PHOSPHATE
FLUORIDE
Acidulated phosphate fluoride (APF), one of the most
commonly used fluoride gels, is known to etch glass by
selective leaching of sodium ions, thereby disrupting the
silica network.
Use of lower concentrations( 0.4% stannous fluoride and
2% sodium fluoride)-no significant effect
Avoid the use of APF gels when composites and ceramics
are present.
Should not be used on glazed porcelain surfaces. If such a
gel is used, surface of the restoration should be protected
with petroleum jelly, cocoa butter, or wax.
189. PORCELAIN DENTURE TEETH
Denture teeth are made by packing two or more
porcelains of differing translucencies(High fusing
porcelains) for each tooth into metal molds.
They are fired on large trays in high-temperature ovens.
Porcelain teeth are designed to be retained on the
denture base by mechanical interlocking.
190. • are made with
projecting metal pins
that become
surrounded with the
denture base resin
during processing,
Anterior
teeth
• are molded with
diatoric spaces(holes)
into which the
denture base resin
may flow.
Posterior
teeth
191. DISADVANTAGES
more esthetically satisfactory
(natural looking)
much more resistant to wear
Excellent biocompatibility
only type of denture teeth
that allow the denture to be
rebased (replacement of the
entire acrylic denture base)
Brittleness
Need for mechanical retention
Extra time required to grind
and contour the surfaces
Clicking sound produced on
contact with the opposing
teeth.
Higher density;increased
weight
Require a greater interridge
distance because they cannot
be ground as thin in the ridge
lap area as acrylic teeth
without destroying the diatoric
channels that provide their
only means of retention to the
denture base resin.
ADVANTAGES
192. SHADE GUIDES
Shade guides are produced by dental ceramic
manufacturers
1.to assist dentists and lab technicians in selecting optimum
ceramic shades
2. for communicating the desired prosthesis appearance to
each other.
Shade guides made of porcelain are used most often by
dentists to describe a desired appearance of a natural
tooth or ceramic prosthesis.
193.
194. Hue-is the basic color
A
SHADES OF
ORANGISH
BROWN
B
SHADES OF
YELLOW
D
YELLOWISH
BROWN
Chroma is
the intensity of
that color, so
that a higher
degree of
chroma would
have a higher
concentration
of hue.
Value is the
amount of
grayness or
whiteness. To
lower the value
means to
darken, and to
raise the value
means to
lighten. The
"C" shades can
be used to
indicate four
basic values.
195. Value Saturation Hue
DetermineThe Lightness
Level (Value)
• Hold shade guide to
patient’s mouth at
arms length
• Start with darkest
group moving
right to left
• SelectValue group 1, 2,
3, 4, or 5
From your
selectedValue
group,
remove the middle
tab (M) and
spread the
samples out like a
fan
Select one of the
three shade
samples
to determine
Chroma/saturatio
n
Check whether
the natural
tooth is
more yellowish
or more reddish
than
the shade
sample
196. Deficiencies of shade guides
1. Shade guide tabs are much thicker than the thickness of
ceramic that is used for dental crowns or veneers, and they
are more translucent than teeth and ceramic crowns backed
by a nontranslucent dentin substructure or veneering
ceramics backed by an opaque core ceramic, or a metal
framework
2. Much of the incident light is transmitted through a tab. In
contrast, most of the incident light on a crown is reflected
except at the incisal edge and at proximal incisal areas.
3. the necks of shade tabs are made from a deeper hue—that
is, higher chroma—and this region tends to distract the
observer’s matching ability in the gingival third of the tab.To
avoid this situation, some clinicians grind away the neck area
of a set of shade tabs
197. The VITA Easyshade
It is a simple-to-use point and click digital
spectrophotometer that provides instant dental
shade readouts regardless of the lighting conditions.
• Defines how the desired shade is developing between
biscuit firings, regardless if the crown is wet or dry.
• This approach assures that the final
success of the shade will exhibit
color from within, rather than a
stained external surface
.
198. Fracture of ceramic-ceramic prostheses
(Hientze and Rousson-2010)
• Need polishingGrade 1
• Need repairGrade 2
• Need replacementGrade 3
199. Repair of ceramic restorations
Porcelain
etching gel(HFl
acid)
Bonding agent
Opaquer(mask
the metal)
Glaze
200. Repair of ceramic restorations
Gingival
tissues are
protected
with a
protective
gel(Kool
Dam)
Ceramic is
etched with
the gel
Bonding
agent is
applied and
light cured
Opaquer(for
metal
ceramics)
After
trimming and
shaping –final
glaze
For bulk repair a regular light cured composite is used
201. FACTORS ASSOCIATED WITH FRACTURE
OF ALL CERAMIC PROSTHESES
design
inherent
surface
defects
loading bite force
and load
orientation
processing
defects
diet
procedural
errors
residual
stress
material
properties
202. Factors contributing
to
Surface
treatment Excessive
loading
during try in
Bruxing
loads
Loading
location
Load
distribution
Load
magnitude Transient
cooling
stresses
Crack
propagation
chipping
Crack
initiation
Bulk
fracture
Residual
cooling
stresses
Inadequate
tooth
preparation
Improper
core
framework
design
Inadequate
crown
thickness
Inadequate
core
thickness
Improper
connector
size
Quality of
cement
layer
Bond
quality of
ceramic
veneer to
core
ceramic
Voids in
cement
layer or at
cement
ceramic
interface
Elastic
moduli of
components
Elastic
moduli of
supporting
substrate
materials
203. How to reduce risk for ceramic fracture?
Sufficient tooth
reduction
Adequate prostheses
design
Distributed vertical
loading
sufficient thickness of
ceramics
meticulous attention
to the recommended
manufacturers’
procedures
204. Selection criteria for dental ceramics
Esthetic
demands of
patient
Type of
luting
cement
Amount
of tooth
reduction
205. Selection criteria for dental ceramics
• All types of metal ceramics
• up to 2nd molar
Single crowns
• Glass ceramics
• up to pre molars
• Maximum of four units
Anterior bridge
• Zirconia-based ceramicsLong span
bridges
• Zirconia based restorations
• Only when adequate tooth preparation is possible
• Proper veneering of zirconia core
Anterior
esthetic zone
206. How to make a decision?
Material to
be
used/design
Intra oral
conditions
Esthetic
needs
expectations
Financial
resources of
the patient
Anticipated
success
rates
Survival
time
Minimize
risk factors
Optimal
treatment
options
207. Longevity of ceramic restoration
Factors
Material factors
Dentist,lab,technician
factors
Patient factors
Operator reliability
Prevailing oral conditions
Longevity
Metal ceramic
restorations
5-8 years
All ceramic
restorations
15 years-up to
90% retention
3-5 years-100%
retention
208. Survival rate of all ceramics
Powder
condensation
CAD-CAM
ceramics
Hot
pressing
technique
209. IDENT-CERAM System for identification of
ceramic products
Introduced in 2007
To identify
1.manufacturer/company
2.brand name
3.composition of materials
Six in number
Recognizable letter code-
helps to ensure proper
insurance coding
practical way to document
informations
210. The letter codes
Ident Ceram Ident Alloy
• FDA LISTED ALUMINIUM OXIDE
AO
• FDA APPROVEDYTTRIUM
ZIRCONIAYZ
• FDA REGISTERED LITHIUM
DISILICATE GLASS CERAMICLD
• FDA CLEARED LEUCITE GLASS
CERAMICLG
• FDA REGISTERED
• FLUORAPATITE GLASS CERAMICFE
• FDA REGISTERED LEUCITE GLASS
LE
• HIGH NOBLE
HN
• NOBLE
N
• PREDOMINANTLY BASE
METAL
PB