Recent advances in dental materials /certified fixed orthodontic courses by Indian dental academy

GOOD AFTERNOON

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


RECENT ADVANCES IN
DENTAL MATERIALS
Presented by
Dr. A. Premalatha
Final M.D.S
Dept.Of Prosthodontics

CONTENTS
INTRODUCTION
CLASSIFICATION
HISTORY
IMPRESSION MATERIALS
DENTAL LUTING AGENTS
DENTAL CERAMICS
DENTURE BASE RESINS
CONCLUSION
REFERENCES

INTRODUCTION
The overriding goal of dentistry is to maintain or improve
the life of the dental patient . The main challenges for
centuries have been the development and selection of
biocompatible,

long

lasting,

direct

filling

tooth

restoratives and indirectly processed prosthetic materials
that can withstand the adverse conditions of the oral
environment.


HISTORY
About 3000 B.C Gold bands and wires were
used by the Phoenicians (After 2500 B.C) .
Around 600 A.D The Mayans used implants
consisting of sea shell segments that were
placed in anterior teeth sockets.
Fauchard (1678-1761) the father of modern
dentistry used tin foil and lead cylinders for filling
the tooth cavities.

In 1756 Phlip Pfaff of Germany described a method for
making impressions .
In 1774 Duchateau a French pharmacist designed a
process for producing hard , decay proof porcelain
dentures.
Planteau, a French dentist first introduced porcelain
teeth in 1817.
In 1839 Charles Goodyear has invented vulcanized
rubber denture bases , and in 1935 polymerized acrylic
resin was introduced as a denture base material.

CLASSIFICATION
Preventive materials
Restorative materials
Auxiliary materials


IMPRESSION MATERIALS
CLASSIFICATION
Based on setting mechanism
Based on mechanical properties
Based on the uses
Based on their use in dentistry
Based on the amount of pressure applied
Based on the manipulation
Based on the tray used for impression

Plaster
Non-elastic

Compound
Waxes

Impression
Materials

ZnO - Eugenol

Aqueous
Hydrocolloids
Elastic

Agar (reversible)
Alginate (irreversible)
Polysulfide

Non-aqueous
Elastomers

Silicones
Polyether


Condensation
Addition

AGAR HYDROCOLLOID
Indications
– crown and bridge
high accuracy

Example
– Slate Hydrocolloid
(Van R)


AGAR HYDROCOLLOID
COMPOSITION:
Agar- 13-17%
Borates -0.2-0.5%
Sulfates-1-2%
Diatomaceous earth, clay, silica
Thymol
Glycerin
Water-85%
(sol)

(gel)
HEAT TO 43degree

Agar hydrocolloids (hot)

Agar hydrocolloid (cool)

HEAT TO 100 degree


Available as
-syringe material
-tray material


3-chamber conditioning
unit
– (1) liquefy at 100°C for
10 minutes
converts gel to sol

– (2) store at 65°C
– place in tray
– (3) temper at 46°C for 3
minutes
– seat tray
– cool with water at 13°C for 3
minutes
converts sol to gel


RECENT TECHNIQUES

Laminate technique
Wet field technique


LAMINATE TECHNIQUE
Is the combined agar – alginate technique
Tray material- chilled alginate
Syringe material –agar
Advantages
-water cool tray is not required
-syringe agar records the tissues
more accurately
Disadvantages
-agar- alginate bond failure.
-technique sensitive.

WET FIELD TECHNIQUE
The oral tissues are flooded with warm water.
The syringe material is injected over the surface
to be recorded.
Before the syringe material gels tray material
placed.
The hydraulic pressure of the viscous tray
material forces the fluid syringe material down in
to the areas to be recorded.

ALGINATE HYDROCOLLOID
Most widely used
impression material
Indications
– study models
– removable fixed partial
dentures
framework

Examples
– Jeltrate (Dentsply/Caulk)
– Coe Alginate (GC America)

ALGINATE HYDROCOLLOID
COMPOSITION:
Potassium alginate -18%
Calcium sulphate
dihydrate -14%
Sodium phosphate -2%
Diatomaceous earth or
silicate powder -56%
Organic glycols
Winter green oil
Pigments
Disinfectants

MANIPULATION
Weigh powder
Powder added to water
– rubber bowl
– vacuum mixer

Mixed for 45 sec to 1 min
Place tray
Remove 2 to 3 minutes
– after gelation (loss of
tackiness)


RECENT DEVELOPMENTS
Dust free alginates
Siliconised alginates
Low dust alginates
Antiseptic alginates
Color indicating alginates


DUST FREE ALGINATES
Dustless alginates
contain no dust
particles so avoiding dust inhalation.
This can be achieved by coating the
material with glycerine or glycol.
This causes the powder to become more
denser than in uncoated state.

SILICONIZED ALGINATES
It is a two component system in the form
of two pastes, one containing the alginate
sol and the second containing the calcium
reactor.
The components incorporate a silicone
polymer component which makes material
tear resistant compared to unmodified
alginates.

ANTISEPTIC ALGINATES
Introduced by Tameyuki Yamamoto, Maso Abinu
patented in 1990.
o.01 to 7 parts by weight of an antiseptic such as
glutaraldehyde and chlohexidine gluconate per
100 parts
The antiseptic may be encapsulated in a
microcapsule or clathrated in a cyclodextrin.

LOW DUST ALGINATES
– Introduced by Schunichi, Nobutakwatanate in
1997.
– sepiolite and a tetraflouroethylene resin
having a true specific gravity of from 2-3.
– The material generates less dust , has a
mean particle size of 1-40microns.


COLOR INDICATING ALGINATES
Color changes are visualizing the major decision
points in impression making
-end of mixing time
-end of setting time ( tray can be removed
from mouth)
it indicates two color changes
-violet to pink indicates the end of mixing
time.
-Pink to white indicates end of setting time .

Aqueous
Hydrocolloids
Elastic

Agar (reversible)
Alginate (irreversible)
Polysulfide

Non-aqueous
Elastomers

Condensation

Silicones
Polyether


Addition

Polysulfide
First dental elastomers
Indications
– complete denture
– removable fixed partial denture
tissue


Examples
– Permlastic (Kerr)
– Omni-Flex (GC America)

Composition
Base
– polysulfide polymers
– fillers
– plasticizers

Catalyst
– lead dioxide (or copper)
– fillers

By-product
– water

Manipulation
Adhesive to tray
Uniform layer
– custom tray

Equal lengths of pastes
Mix thoroughly
– within one minute

Setting time 8 – 12
minutes
Pour within 1 hour

Condensation Silicone
Indications
– complete dentures

Examples
– Speedex (Coltene/Whaledent)
– Primasil (TISS Dental)


Composition
Base
– poly(dimethylsiloxane)
– tetraethylorthosilicate
– filler

Catalyst
– metal organic ester

By-product
– ethyl alcohol
Phillip’s 1996

Addition Silicones
AKA: Vinyl polysiloxane
Indications
–
–
–

crown and bridge
denture
bite registration

Examples
–
–
–
–
–

Extrude (Kerr)
Express (3M/ESPE)
Aquasil (Dentsply Caulk)
Genie (Sultan Chemists)
Virtual (Ivoclar Vivadent)


Composition
Improvement over
condensation silicones
– no by-product

First paste
– vinyl poly(dimethylsiloxane)
prepolymer

Second paste
– siloxane prepolymer

Catalyst
– chloroplatinic acid
Phillip’s 1996

Polyether
Indications
– bite registration

Examples
– Impregum F (3M/ESPE)
– Permadyne (3M/ESPE)
– Pentamix (3M/ESPE)
– P2 (Heraeus Kulzer)
– Polygel (Dentsply Caulk)

Composition
Base
– difunctional epimine-terminated prepolymer
– fillers
– plasticizers

Catalyst
– aromatic sulfonic acid ester
– fillers

Cationic polymerization
– ring opening and chain extension

RECENT ADVANCEMENTS
Hydrophilized addition silicone.
with the incorporation of non ionic
surfactants as micelles.
This increased wettability allows
the addition silicones to spread
more freely along the surface
Miller and coworkers reported
modified polydimethyl siloxane
wetting agent (extrinsic surfactant)

Recently radiofrequency glow discharge
has been advocated for use as a
disinfecting procedure for polyvinyl
siloxane impressions.
Whilst this procedure is claimed to clean
and improve the wettability of the
impression surface

MONOPHASE IMPRESSION
MATERIALS
These materials can be used as both light
bodied and heavy bodied materials.
The amount of pressure given during mixing
determines the viscosity. The greater the shear
the thinner the viscosity.
If more pressure is used it can be used as a light
bodied material if less pressure is used it acts as
a heavy bodied material.

Visible light cured poly ether
urethane
Composition includes:
-polyether urethane dimethacrylate
- diketone – photo initiator
- transparent silica – filler (40-60%)


MANIPULATION
Transparent stock trays are available.
The light bodied material is syringed and the
heavy body material is placed above it.
Blue light is used for curing. The exposure
should be done from the posterior to anterior
region. Each region should get an exposure of
30sec.

Advantages:
Long working time, but short setting time.
Impressions can be corrected.
Dimensional stability ,flow, detail
reproduction .
Disadvantages:
Expensive
Requires special equipment

LUTING CEMENTS
A dental cement used to attach indirect
restorations to prepared teeth is called a
luting agent .
Luting agents may be definitive or
provisional depending on their physical
properties and the planned longevity of the
restoration.

CLASSIFICATIONS
Craig’s classification based on the chief ingredients eg:
zinc phosphate, zinc silicophosphate, zinc oxide
eugenol, zinc polyacrylate, glass ionomer, and resin.
O’Brien classified dental cements by matrix and bond
type (eg: phosphate, phenolate, poly carboxylate, resin,
resin modified glass ionomer)
Donovan classified cements into conventional (eg:zinc
phosphate,polycarboxylate,
glass
ionomer)
and
contemporary (eg:resin modified glass ionomer, resin )


Resin modified glass ionomer
(RMGI)
Introduced in 1980’s.
part of the water component of glass poly alkenoate
cement was replaced with a water hydroxyl methyl
methacrylate (HMMA) mixture plus an initiator/ activator
for the added resins.
Resin modified glass ionomer is a dual cure hybrid.
The acid base reaction continues to develop a polysalt
hydrogel matrix which hardens and strengthens the
existing polymer matrix.

COMPOMERS
appeared in the late 1990’s, and were described as
being a combination of composite resin (comp) and
glass ionomer (omer).
Compomers are anhydrous resins that contain ion
leachable glass as part of the filler and dehydrated poly
alkenoic acid.
higher compressive and flexural strength than RMGI, but
inferior to unmodified composite.
Tooth addition is very little , fluoride release is very
limited and it’s less than that of conventional glass
ionomer .

RESINS
Resin cements are methyl- methacrylate, BisGMA dimethacrylate or Urethane dimethacrylate
based with fillers of colloidal silica or barium
glass 20-80% by wt.
They
are
available
as
powder/liquid,
encapsulated or paste/paste systems and may
be auto, dual or light cured to form the polymer
matrix.
Resin bonding to enamel is by mechanical
interlocking into an acid etched surface.

ADHESIVE RESINS
In the early 1980’s conventional Bis GMA resin
cement was modified by adding a phosphate
ester to monomer component.
Eg; Panavia – contained the bifunctional
adhesive monomer 10- methacryloyloxy deci
dihydrogen phosphate (MDP) and was a
powder/ liquid system
the current product Panavia F is a two paste
system that is dual cured , self etching and self
adhesive plus fluoride releasing

Dong xie, Youfun yang et al had
developed a novel comonomer free light
cured glass ionomer system based on 4
arm star shape poly acrylic acid.
has significantly improved mechanical
strength, and no invitro cytotoxicity
observed.

GC
America announces Fuji CEM
Automix , the first automix delivery
system available in a resin modified glass
ionomer.
Fuji CEM
Automix requires no hand
mixing and dispences a consistent mixing
ratio directly into the restoration.

Def:
An inorganic compound with nonmetallic
properties typically consisting of oxygen
and one or more metallic or semimetallic
elements (eg: aluminium, calcium, lithium,
magnecium, potassium, silicon, sodium ,
tin, titanium and zirconium) that is
formulated to produce the whole or part of
a ceramic based dental prosthesis

HISTORY
The porcelain tooth material was patented in 1789 by French dentist
de Chemant in collaboration with a French pharmacist Duchateau.
In 1808, Fonzi an Italian dentist invented a terrometallic porcelain
tooth that was held in place by a platinum pin or frame.
Planteau, a French dentist introduced porcelain teeth to united
states in 1817 and Peale an artist.
Ash developed an improved version of the porcelain tooth in 1837.
Dr Charles land introduced one of the first ceramic crowns to
dentistry in 1903


Pressable glass ceramic (IPS Empress )
was introduced in early 1990’s,
A more fracture resistant, pressable glass
ceramic (IPS Empress 2) was introduced
in the late 1990’s.


CLASSIFICATION
Based on chemical composition
Based on crystalline nature
Based on fusion temperature
Based on type
Based on the method of fabrication
Based on application
Based on sub structural material
Based on use
Based on firing
Classification based on recent types of
ceramics

Classification based on recent types of ceramics
– castable glass ceramics eg: Inceram, alumina,
Inceram, spinell
– pressable ceramics EG: Optec HSP, IPS empress
– CAD – CAM ceramics eg: cere vitablock markI,
vitablock mark II
– Injection molded ceramics eg: Optec HSP

Castable glass ceramics
– EG Inceram, alumina, Inceram, Spinell, Dicor
and Dicor MGC
– Castable ceramic systems are used to cast
crowns by the lost wax process.
– Indicated in cases of single anterior and
posterior crowns
– An ingot of the ceramic material is placed in a
special crucible and melted and cast with a
motor driven centrifugal casting machine at
1380 degree C.

Hot pressing
Eg: IPS Empress, IPS Empress 2, IPS e max press,
OPC
pressure molding is used to make small intricate
objects .
IPS Empress is a glass ceramic provided as core ingots
that are heated and pressed until ingot flows in to a
mold.
It contains a higher conc. of leucite crystals that increase
the resistance to crack propagation (fracture).

Machinable ceramics
Computer aided design / computer aided
manufacturing
There are two popular systems available
for machining all ceramic restorations
-CEREC System (siemens,
Bensheim, Germany)
-Celay system (Mikrona
technologies, Switzerland)

CEREC SYSTEM
HISTORY:
It was introduced by Werner H.Mormann (1980) at the university of
Zurich.
The first chair side CEREC introduced in 1985.
In 1994 CEREC -2 was introduced.
In 2000 CEREC -3 was introduced.
In 2003 , 3D soft ware version is released, allowing users to see 3D
views of teeth and models
In 2008, Sirona release the MCXL milling unit , this milling unit can
produce a crown in 4 minutes.

CEREC - I
introduced in 1985
chief indications are single
dual surface inlays and
material is vitablocs markII

and
the

The concept of grinding inlay
bodies externally with a grinding
wheel along the mesiodistal axis
suggested itself.


CEREC - II
– introduced in 1994
– additional cylinder
diamond enabling the
form grinding of partial
and full crowns.
– An upgraded 3D
camera was provided.


CEREC - III
skipped the wheel and introduced the two bur
system.
It’s a compact windows based CAD- CAM system


CELAY system
The celay system (Mikrona technologie,
spreitenbach, Switzerland) uses a copy milling
technique to manufacture ceramic inlays or
onlays from resin analogs.
The Celay system is a mechanical device based
on pantographic tracing of a resin inlay or onlay
fabricated directly on to the prepared tooth or on
to the master die (Eidenbenze U/1994).

DENTURE BASE RESINS
Poly (methyl methacrylate) polymers were
introduced as denture base materials in
1937.
previously used materials:
vulcanite , nitrocellulose, phenol
formaldehyde, vinyl plastics and porcelain


CLASSIFICATION
Based on the duration of use
Based on the material used
Based on the chemical composition of
the resins
Types of acrylic resins
-based on their mode of activation
-based on filler particles

EVOLUTION
Acrylic acid and its derivatives came to be well known by the 1890’s
Dr.ottorohm is considered as the father of Recent acrylic. He
introduced polymers of acrylic acid in 1901.
1927
acryloid
and
plexigum
both
polymers
polymethylmethacrylate were introduced by Rohm and Haas.

of

In 1931 commercial production of harder poymethyl methacrylates
occurred with the introduction of plexiglass (also known as organic
glass, leucite I plexite)
Acrylic resins came in to use in dentistry between 1930 and 1940.
they are used in dentistry as denture base materials.


RECENT ADVANCEMENTS
Pour type acrylics
High impact strength acrylics
Rapid heat polymerized acrylics
Light activated acrylics
Reinforced denture base materials

Pour type acrylics
The principle difference is in the size of the polymer
powder or beads.
smaller powder particles, when mixed with monomer the
resulting slurry is very fluid.
The mix is quickly poured in to an agar hydrocolloid or
modified plaster mold and allowed to polymerze under
pressure at 0.14MPa.
Centrifugal casting and injection molding are technique s
used to inject the slurry into the mold.

High impact strength acrylics
These polymers are reinforced
butadiene –styrene rubber.

with

These materials are supplied in a powderliquid form and are processed in the same
way as other heat accelerated methyl
methacrylate materials.


Rapid heat polymerizing acrylics
The initiator is formulated from both
chemical and heat activated initiators to
allow rapid polymerization without the
porosity.
After placing the denture in boiling water
the water is brought back to a full boil for
20min.

Light activated acrylics
This denture base material consists of a urethane
dimethacrylate matrix with an acrylic copolymer ,
microfine silica fillers and a photoinitiator system.
It’s supplied in premixed sheets having a clay like
consistency.
The denture base material is adapted to the cast while
it’s still pliable
The denture base can be polymerized in a light chamber
with blue light of 400-500nm.

Reinforced denture base resins
Glass fillers
Carbon / graphite fillers metal fillers
Aramid fillers
Polymer fiber composites
Ultra high modulus polyethylene fibers
(UHMP).
Aluminium oxide addition

Introduction of a denture injection
system for use with microwavable
acrylic resins


In the GC INJECTION system a pneumatic
press is used to force unpolymerized acylic resin
into the mold cavity.
A modified microwavable flask is used to
facilitate this process .
The modified flask has a small channel in its lid
that permits a small diameter sprue (7mm)to
pass from the external surface of the flask in to
the mold cavity.


Development of a radio-opaque
auto polymerizing dental acrylic
resin
There are many materials which can act as radio
opaque additives eg;Barium sulfate, Barium
acrylate, Bismuth bromide
Patrik A..Mattie et al (1994) proposed a
component that is Triphenyl Bismuth has a very
low level of cytotoxicity which
indicates
significant biocompatibility.

CONCLUSION
It is the goal of medical procedure to provide the
best treatment for the patient while following the
Hippocratic oath: “First , do no harm”. As dentists , we
are challenged to restore function while providing a
highly esthetic result .
An examination of material properties should
lead us to select those systems engineered to provide
the patient with best clinical out come with respect to
esthetics , function , longevity and compatibility with
surrounding natural tissues.

REFERENCES
Restorative Dental materials:G Craig & John M Powers-11th
edition2002.
Phillips science of dental materials: Anusavice; 11th edition
DCNA, July 2007, 994-1003.
O’Brien, Dental Materials & their Selection 1997
Evolution of dental ceramics in the twentieth century, John
W.Mclean, JPD VOL-85, NO.1, Jan-2001.
A novel comonomer –free light-cured glass – ionomer cement for
reduced cytotoxicity and enhanced mechanical strength. Dong
Xie, J of Dental materials 23 (2007) 994-1003.
The effect of disinfection and a wetting agent on the wettability of
addition silicone Impresion materials; Paul J.Milward, JPD 2001;
86.165-7.

Introduction of a denture injection system for use with microwaveable acrylic
resins; R,D Phoenix, JOP, V ol 6, No.4, DEC1997, pg286-291.
JOP , 2004,VOL13, NO.2(june), pg 83-89
JOP; VOL-2, No.3 ,sept 1993; pg 174-177
JOP; VOL-3,No.4 DEC.1994;pg 213-218
Poly vinyl siloxane impression materials ; an update on clinical use; Michael
N.Mandiko; Australian dental journal ,1998, 43 (6); 428-434.
JOP; xx (2008) 1-6
JOP; VOL-5, No.4 DEC,1996, PG 270-76
JOP; VOL-8, No.1 march 1999, pg 18-26
Clinical performance of chair side CAD/CAM restorations;JADA, VOL 137,
22-31
The evolution of the CEREC system; Werner H. Mormann, JADA, vol 137,
2006
Materials for chairside CAD/CAM produced restorations, Russell
GIORDANO;JADA, vol 137 ,2006 14

ACKNOWLEDGEMENTS
TO
ALL THE STAFF MEMBERS
DEPT. OF PROSTHODONTICS
SIBAR INSTITUTE OF DENTAL SCIENCES


Recent advances in dental materials /certified fixed orthodontic courses by Indian dental academy

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