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

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


RECENT ADVANCES IN GLASS IONOMER CEMENTS
• IMPROVED TRADITIONAL GLASS IONOMERS
HIGHLY VISCOUS GIC / PACKABLE GIC/
CONDENSABLE GIC
LOW VISCOSITY GIC
• METAL – MODIFIED GLASS IONOMERS
MIRACLE MIX
CEREMET
• RESIN MODIFIED GLASS IONOMERS
• POLY ACID- MODIFIED COMPOSITE RESINS /
COMPOMERS
• SELF- HARDENING www.indiandentalacademy.com
GLASS IONOMERS

• NEW FLUORIDE RELEASING GLASS IONOMERS:
-

LOW Ph “SMART” MATERIALS

-

FLUORIDE CHARGE MATERIALS

• BIOACTIVE GLASS
• FIBRE – REINFORCED GLASS IONOMER CEMENTS
• GIOMERS

IMPROVED TRADITIONAL GLASS IONOMERS
HIGHLY VISCOUS GLASS IONOMER
Due to the possibility of reduced secondary caries by
fluoride release and to the comparative ease of use of
conventional glass ionomers, further developments have
been made for posterior restorations in primary and
permanent dentition.

This material was developed largely as a response to the
need for filling materials in the atraumatic Restorative
Therapy or “ART”.


ART refers to the restorations of teeth under
conditions of minimal instrumentation currently in use
in third world nations where full dental care is not
always available.


ADVANTAGES OF PACKABLE GIC OVER
CONVENTIONAL GIC ARE:


They are packable and condensable



They are easy to place



They are non-sticky



Early moisture sensitivity is reduced




Rapid finishing can be carried out



Improved wear resistance.



Low solubility in oral fluids.


DISADVANTAGES OF THESE GIC’S ARE:


Due to their opacity, they have esthetic disadvantages



They have limited life potential.



Moderately polishable


LOW VISCOCITY GLASS IONOMERS
This type of glass ionomer has been developed as liners, fissure
protecting materials for hypersensitive cervical areas and
endodontic materials. Such materials are designed with low
powder-liquid ratios and highly flowable.
These are used as fissure protection materials during the eruption
Period of the teeth.

METAL – MODIFIED GLASS IONOMER CEMENTS
Glass ionomer cements lack toughness and hence,
cannot withstand high-stress concentrations. GIC have
been modified by the inclusion of metal filler particles
in an attempt to improve toughness
Two methods of modifications have been employed.

SILVER ALLOY ADMIX or MIRACLE MIX
Sced and wilson (1980) found that amalgam alloys could
be incorporated into glass ionomer cements and that these
served to increase the flexure strength. Spherical silver
amalgam alloy powder is mixed with Type II glass
ionomer powder in the ratio 7:1.

CERMET – IONOMER CEMENTS:
In an attempt to improve the abrasion resistance and strength
of GIC, McLean and Gasser(1985) developed the “cermet”ionomer. These cements, unlike simple mixtures of alloy
particles or metal fibres, contain glass-metal powders sintered
to high density that can be made to react with polyacids to
form a cement.


INDICATIONS:


As an alternative to amalgam in conservative Class I
cavities in primary teeth.



Core build –up material



Lining of class II amalgam restorations.



Root caps for teeth under overdentures



Preventive restorations and temporary posterior

restorations.


CONTRAINDICATIONS:
Anterior restorations.
Areas subjected to high occlusal loading.


RESIN – MODIFIED GLASS IONOMER CEMENT:
Low early strength and moisture sensitivity of the traditional
glass ionomer was the result of slow acid-base reactions.
Hence to overcome these two inherent drawbacks, some
polymerizable resin functional groups have been added to
GIC to impart additional curing process and allow the bulk
of the material to mature through the acid-base reaction.

DEFINITION:

“Resin –modified glass ionomer materials that are
modified by the inclusion of resin, generally to make them
more photocurable”


POWDER:

The powder component of a typical light- cured material
consists of ion leachable glass and initiators for light or
chemical curing or both


LIQUID:
The liquid component usually contains water, polyacrylic
acid with or without some carboxylic acid modified with
methacrylate and Hydroxyethyl methacrylate monomers.

POWDER : LIQUID RATIO = 3:1.


ADVANTAGES


Can be finished and polished immediately after set



Repairs can be carried out, as bond between old and

new material is very strong.


Exhibits increased adhesion to composite when used a

base




Ideal under composite as it can be etched immediately



Fluoride release is greater than conventional GIC and

compomers


High diametral strength of 20MPa


DISADVANTAGES:
-

Biocompatibility is controversial
Setting shrinkage is higher (-1%) and hence,

microleakage is more and marginal adaptation is poor
-

Lower wear resistance as compared to composite.


USES:
•

Used as a liner and base

•

Pit and fissure sealant

•

Core build-up material


POLYACID – MODIFIED COMPOSITE RESINS
“COMPOMERS”
A new variety of

the usual composite resins comprising

resins and inorganic filler particles is the polyacid-modified
composite resin or “compomer” which was introduced in the
early 1900s.


The compomer - combination of “comp” form composite
and “omer” from glass ionomer was introduced as a type of
glass ionomer, with claims that it offered some fluoride
release as well as improved physical properties and clinical
characteristics.


DEFINITION:
Compomer can be defined as a resin composite with fluoride
releasing Potential.
Polyacid – modified glass ionomer cement is defined as
materials that may contain either or both of the essential
components of glass ionomer cements but at levels insufficient
to promote the acid- base curing reaction in the dark.


COMPOSITION:
The compomers presently available contain resins and fillers
common to composite resins and glass ionomers. They
include reactive ion-glass particle and polymerizable acidic
monomers. They are usually one Component material.


PROPERTIES OF COMPOMERS
COMPRESSIVE STRENGTH

180-240

FLEXURAL STRENGTH (MP a)

65-125(-96)

DIAMETRAL TENSILE STRENGTH

25-40

FLEXURAL MODULUS (Gpa)

4.5-14(-14)

AVERAGE FILLER SIZE (u m)

0.8-5

VOLUME% OF FILLER

42-67

DEPTH OF CURE (mm)

4.7

FLUORIDE RELEASE (ug / cm2)

7.8

BOND STRENGTH TO DENTIN(MPa)

18.24 with dentin
bonding agent

SOLUBILITY IN WATERwww.indiandentalacademy.com
(% in 24 hrs)

Low

INDICATIONS:


Sealing and filling of occlusal pits and fissures



Restorations of primary teeth



Minimal cavity preparations



Lining



Core build-up




Repair of defective margins in restorations



Restorations of class III cavities



Restoration of Class V lesions



Restorations of erosion lesion



Sealing of root surface for over dentures



Potential root canal sealers



Retrograde filing materials in endodontic surgeries

CONTRA INDICATIONS


Class IV carious lesions



Lesions involving large areas of labial surface



Class II carious lesions where conventional cavities are
prepared



Lost cusp areas



Under full metal or PFM crowns where light cannot
penetrate

ADVANTAGES


Superior working characteristics to RMGIC



Ease of use



Easily adapts to the tooth



Good esthetics


TYPE II GIC

METAL
MODIFIED GIC

RESIN
MODIFIED GIC

COMPRESSIVE
STRENGTH(Mpa)

150

150

105

DIAMETRAL
TENSILE
STRENGTH(MP a)

6.6

6.7

20

HARDNESS(KHN)

48

39

40

PULP RESPONSE

Mild

Mild

Mild

ANTICARIOGENIC

Yes

Yes

Yes

SOLUBILITY

0.4

FLUORIDE
RELEASE (ug F)
14 days
30 days

440
650

200
300

1200
1600

BOND STRENGTH
MPa

1.1-4.5(to
<TYPE II
dentin)

13.4

DIRECT COMPARISON OF CONVENTIONAL GIC, RMGIC AND COMPOMER
CHARACTERISTIC

CONVENTIONAL GIC

RESIN
MODIFIED GIC

POLYACID
MODIFIED GIC

Handling properties/
preparation of the
material

Powder-liquid
systems, aqueous
based; hand-mixed
versions or
precapsulated
systems

Powder – liquid
Systems, Watermonomer based;
hand-mixed or
Precapsulated
systems

One component
material, no water
and no
mixing

Working time

1-2 minutes

Several
minutes (setting
initiated by light
curing)

Unlimited (light
Cured)

Setting mechanism

Acid – base
reaction (4-8 minutes),
second phase within the
next 24 hours

Light curing (40
seconds); radical
Polymerisation and
acid –base reaction

Light curing only
(40 seconds);
Incremental
technique


Moisture sensitivity
after placement

High, especially
Moderate to low
during first setting
Stage ( protective
covering required

None

Final finish

Fair

Excellent

Adhesion to tooth
Structure

Self adhesive;
Self adhesive;
chemical bond to Primer needed for
enamel and dentin Certain products

Strength

High compressive
strength; low
flexural strength

High compressive
Strength; medium
flexural strength

Wear resistance

Low ; highly
Viscous cementsModerate to
acceptable

Poor

Good


SELF

HARDENING

RESIN

GLASS

IONOMER

CEMENTS
This is another recent development in resin – modified glass
ionomer Luting cements. These contain certain monomers
with initiators to allow self polymerization similar to those
used in cold-cure acrylics It mainly contains benzoyl
peroxide and amine added to the glass Ionomer.

Its advantages are:
•

Easy to handle

•

No significant post- cementation sensitivity

•

Significant fluoride release

•

High compressive and fracture strength

•

No light activation required

1. FLUORIDE CHARGED MATERIALS
This is a modified glass ionomer and is a two part material

Restorative part

Charged part


2.

LOW pH ‘SMART’ MATERIALS
This materials is based on the fact that fluoride should
be released at a low pH i.e. when caries attack may be

most threatening.
Hence, they are called ‘smart’ materials. The fluoride
release is episodic and not continuous. This prolongs the
therapeutic usefulness of the material and optimises the
fluoride release. www.indiandentalacademy.com

BIOACTIVE GLASS
The idea of bioactive glasses was developed by Hench
and co. in 1973.

This is an excellent material for use in maxillofacial and
craniofacial

surgeries

as

it

performs

hydroxyapatite.

better

than

USES


Augmentation of alveolar ridges in edentulous

arches


Cementation of custom made implants into place



Correction of intra-bony pockets in periodontology



May help in the formulation of bioglass ceramics-

with superior strength for fabricating crowns.

FIBRE- REINFORCED GLASS IONOMER CEMENTS:

Newer developments in resin-modified glass ionomer
cements has lead to the incorporation of alumina fibres into
the glass powder to improve upon its flexure strength. This
technology is called polymeric Rigid Inorganic Matrix
Materials or PRIMM

GIOMERS:

SHOFU used the hybridization of glass ionomer and
composite rein to develop a new family of fluoride
releasing direct aesthetic restoratives and adhesion called
GIOMER characterised by pre-Reacted Glass ionomer
(PRG)


Thank you

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

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