3. Definition:
It is a natural gum like copal resin or synthetic
resin dissolved in organic solvents such as ether,
chloroform or alcohol
4. Composition:
Copal and nitrated cellulose are typical examples of natural
gum and the solvents used to dissolve these materials can be
ether, acetone benzene, ether acetate, ethyl alcohol,
chloroform, amylacetate and medicaments such as
chlorobutanol, thymol and eugenol are also added. Recently
fluoride are included in its composition. Flouride varnishes are
used to prevent/arrest decay on smooth surfaces in young
5. Manipulation:
On a patient, Cavity varnish is applied with the help of small
cotton pellet with the help of wire or R.C Reamer or a brush
applicator. Thin layers of varnish are applied on the floor,
walls including cavosurface margins. Gentle stream of air
can be used to remove the excess.Apply a second coat and
the bottle should be tightly capped after use to minimize loss
of solvent.
6. Contraindication:
- Composite – free monomer layer dissolves the varnish
- Ca(OH)2/ ZOE beneficial affects are lost
- Polycarboxylate – interferes with adhesion
- GIC – blocks fluoride penetration.
7. Properties:
1. It is not a physical or mechanical insulator, provides
chemical barrier.
2. Thickness: 2-40µm
3. Always applied in 3 layers to be more effective
8. Uses:
1. 1.Prevents marginal Leakage / Microleakage
2. Prevents penetration of acids from ZnP cement i.e prevents
chemical penetration.
3. Prevents penetration of corrosion products from amalgam
therefore prevents discoloration of tooth.
4. Decreases post operative sensitivity and pain.
5. It may be used as a surface coating over certain restorations
to protect them from dehydration or from contact with oral
fluids until they harden.eg.silicate andGI cements
9. Liners:
Definition: It is liquid in which CaOH and zinc oxide
(occasionally)are suspended in a solution of natural
or synthetic resins.
12. Equal amounts of material from each tube is collected over a
glass slab or mixing pad with help of PD probe both are
mixed till homogeneous colour is got and with same
instrument it is carried -
13. - to deepest portion of the cavity and since it is fluid in
consistency it readily flows or gets painted over the cavity
over which the thermal insulating base or temporary
restoration is provided.
14. Properties:
1. Acts as a thin barrier between the restoration and the
remaining dentine and protects the pulpal tissue from
irritation caused by physical,mechanical,biological, or
chemical agents .
2. Like cavity varnish it neither possesses mechanical
properties nor provides thermal insulation.
15. Uses:
1. As pulp capping agent due to its sealing ability.
2. As anticariogenic cement because it stimulates the
production of secondary or reparative dentin.
3. Prevents post operative sensitivity or pain.
4. It is compatible with all types of restorative materials.
18. Bases :
Chemical and Thermal, Mechanical Insulation
Cements:
General applications
Classification
Individual Cements - Composition
- Manipulation
- Properties
- Uses
19. General Applications:
1. Thermal and chemical insulation
2. Temporary restorations – Zn OE
3. Intermediate restorations – IRM
4. Permanent restorations – GIC
5. Temporary Luting – Type I ZOE
6. Permanent Luting – GIC, ZnP, Zn Poly Carb
20. 7. Cementation of orthodontic appliances
8. As sedative dressing for the pulp of freshly prepared tooth
9. As pulp capping agents
10. Pit and fissure sealants – Composites, GIC
11. Core build-up
12. Root canal sealants Gutta-percha
13. Periodontal dressings
21. Clinical Considerations:
Clinical Judgements about the need for specific liners and
bases are linked to the amount of remaining dentin thickness
(RDT), considerations of adhesive materials, and the type of
restorative material being used.
22. In a shallow tooth excavation, which includes 1.5 to 2mm or
more of RDT, there is no need for pulpal protection other than
in terms of chemical protection. For an amalgam restoration,
the preparation is coated with two thin coats of a varnish, or a
dentin bonding system, and then restored.
23. For a composite restoration, the preparation is treated with a
bonding system (etched, primed, coated bonding agent) and
then restored.
24. In a moderately deep tooth excavation for amalgam that
includes some extension of the preparation toward the pulp so
that a region includes less – than – ideal dentin protection, it
may be judicious to apply a liner only at that site using ZOE or
calcium hydroxide.
25. Either one may provide pulpal medication, but the effects
will be different. ZOE cement will release minor quantities of
eugenol to act as an obtundent to the pulp.
26. How ever, in a composite tooth preparation, eugenol has the
potential to inhibit polymerization of layers of bonding agent
or composite in contact with it.
27. Therefore calcium hydroxide is normally used, if a liner is
indicated. If the RDT is very small or if pulp exposure is a
potential problem, then calcium hydroxide is used to stimulate
reparative dentin for any restorative material.
29. Zinc Phosphate Cement:
Available as Powder and Liquid
Powder.
Zn Oxide – 90%
Mg Oxide – 8-9%
SiO2, Bismuth trioxide, Barium oxide – traces
Liquid.
Phosphoric acid (85%) and water (33+ 5%)
30. Chemistry of Setting:
When the alkaline powder comes in contact with acidic liquid it
partially dissolves in liquid. It is an exothermic reaction. The set
cement consists of hydrated amorphous network of ZnP that
surrounds partially dissolved ZnO2 particles.
35. It is a combination of silicate and ZnP cement
Properties fall between those of ZnP and silicate.
pH: lower than of ZnP
and has got degree of translucency.
Anticariogenic property because of fluorides.
38. Properties:
1. Working time : 3-6mins
2. Setting time 5.5mins
3. Mixing time: 30 to 60secs
4. Compressive strength (24hrs): 8000psi
5. Tensile strength: 900psi
6. Film thickness: 21µm
7. Pulp response: mild
Binds chemically to tooth structure
39. Uses:
Primary Uses
1. Luting agent for cementation of restorations
2. Thermal insulating base
Secondary uses
cementation of orthodontic appliances and intermediate
restorations
40. Advantages over ZnP
- Not irritant to pulp due to high mol. size
- Binds chemically to tooth structure
- Can be used safely in moderately deep cavities.
No need to use cavity varnish.
42. Type I : Temporary luting or cementation
Type II: Permanent cementation ex: kalzinol
Type III: Intermediate restoration, thermal insulating
base, temporary restoration.
Type IV: Cavity liners or subbase
Examples:
Type III: IRM
Type IV: Dycal and life
43. Basic Composition:
As Powder and Liquid
Powder:
ZnO- Main ingredient – 70%
White rosin – reduces brittleness of cement
Zinc acetate – improves strength
Zinc stearate – acts as plasticizer
45. Modifications in basic composition
Type II – Ethoxy benzoic acid/Resins are added increases
the strength of the cement
Type III- Resin reinforced, partially polymerized surface
treated with propionic acid
- Increases strength and abrasive resistance
Type IV – 2 paste system. Active ingredient in both pastes
is Ca OH.
46. Examples: Type I: Tempbond / Neogenol / Freegenol
II: Kalzinol
III: IRM
IV: Dycal
Chemistry of Setting:
ZnO + H2O Zn (OH)2
Zn hydroxide
Zn (OH)2 +2HE ZnE2 + 2H2O
Base Acid Zn – eugenolate salt
48. Mixed on glass slab or mixing pad. Powder is dispensed and
liquid is collected just prior to the mixing. Bulk of the powder
is incorporated into the mixture and spatulated with a stainless
steel spatula till it becomes paste on creamy in consistency.
Powder or cotton fibers can be added which will improve the
retention of the cement in the cavity.
49. Properties:
Setting time : 4-10mins
Compressive strength (after 24hrs): 4000psi
Film thickness: 25um
Solution and disintegration: 0.04% by wt
Pulp response mild
53. Available as powder or 2 paste cements
It is available as dry powder or two paste system.
Mixed either with distilled water or saline to form a paste as
it can also be suspended in chloroform and conveyed to the
required area with the help of a syringe
54. When available as 2 paste cements.
One paste
– monomer of methyl cellulose as initiator and CaOH
Other paste:
Calcium hydroxide and catalyst, when they are brought in
contact methyl cellulose undergoes polymerization and
porous matrix is formed
pH:11
57. Invention,
Composition,
Classification,
Setting Reaction,
Properties,
Variations in basic composition,
Indications,
Contraindications,
Manipulation and clinical procedures for placement.
58. Invented in 1969 but first reported by Wilson & Kent
1971. It was invented in a creative response to inadequate
materials particularly from deficiencies of silicates.
59. 1. It adheres to tooth structure
2. Translucent
3. Releases fluorides
4.Has also all favorable properties
5. Biocompatible and Bioactive
61. POWDER
Consists of calcium aluminosilicate glass containing fluoride.
SiO2 - 30%
Al2O3 - 19.9%
Al F3 - 2.6%
CaF2 - 34.5%
NaF - 2.6%
AlPO4 - 10%
Radioopacifiers like Strontium, Barium and Lanthanum
62. Fluoride is one of the main components.
It lowers fusion temperature,
Improves strength provides translucency and therapeutic
value
and improves working characteristics of the cement
63. Powder particles are obtained by heating all these particles
between 11000 C - 16000 C
64. LIQUID
Polyacrylic acid which is a polyacrylite which is a polymer
of carbonic acid.
Some amount of maleic acid and itaconic acid is added.
Sometimes poly acrylic acid is blended dry with the powder
so that it is mixed with either water or tartaric acid.
66. Type I: As luting agent
Type II: As restorative agent
Type III: Liners and bases and pit and fissure sealants
Type II: Conventional
Reinforced – Metal modified Glass Ionomers
68. When the powder comes in contact with the liquid to form a
paste, surface of powder particles are attacked by liquid. Ca,
Al, Na, F ions are released into the aqueous medium.
69. Calcium polysalts form 1st eventually followed by a Al poly
salts which form cross linking's. They undergo hydration to
form gel matrix and there are untreated powder particles
surrounded by silica gel. Set cement consists of agglomeration
of powder particles surrounded by silica gel in an amorphous
matrix of hydrated Ca and Al polysalts.
71. 1. Translucency – mainly due to fluoride
2. Adhesion
3. Biocompatibility
72. 1. Glass Ionomer cement is an esthetic filling material. Its
translucency arises because of powder particles which is
a clear glass. But it takes 24hrs to achieve, mature and
develop full translucency. Only after this period one can
appreciate the colour match with the adjacent tooth
structure.
Color of GIC remains unaffected by oral fluids unlike
composite resins which tends to discolor.
73. 2. It enables the conservative approach for the
restoration because providing mechanical undercuts to retain
the material is not necessary. This is of particular importance
while restoring cervical abrasions and erosions and there will
be a tight marginal seal. Hence less percolation of bacteria
around cavity margins and walls
74. Type of Adhesion
Chemical bond and can be improved using conditioners
like polyacrylic acid and citric acid.
76. GIC are therapeutic materials. Their adhesion to the tooth
structure ensures a marginal seal thus eliminating secondary
caries by sustained release of fluorides. These materials are not
only biocompatible and bioactive because they promote bone
growth can be used as bone cements after endodontic surgery.
77. The adverse effects on vital tissues are minimal. Hence a
protective barrier is rarely required
4. Setting time 4-5mins
5. Compressive strength (24hrs): 20000 psi
6. Tensile strength: 400 psi
7. Hardness: 60KHN
8. Solubility and disintegration 0.4% by wt
9. Pulp response – Mild
10. Anticariogenic activity.
79. GIC are weak in tensile strength. so incorporation of
metal alloy particles into the powder can reinforce the
cement one such product commercially available is miracle
mix.
80. Here alloy powder particles and glass ionomer powder
particles are mixed by dentist or assistant before mixing
with liquid.
There is improvement in strength.
It does not take up a good surface finish and
cannot be burnished.
Abrasive resistance is less than conventional GIC.
81. Hence in an attempt to improve these properties cermet
ionomer cements were introduced, in this cement metal
alloy particles like Ag and Au are sintered to the powder
particles which have to be mixed with polyacrylic acid to get
a smooth paste.
82. These get a good surface finish and can be burnished and
have good abrasive resistance.
But cannot be compared with composites and amalgam.
83. INDICATIONS:
1.Can be used as a luting agent
2. Can be used for restorations
Restoration of cervical abrasions and erosions without
cavity preparation.
Restoration of class III carious lesions
Restoration of class V carious lesions
84. 3. Pit and fissure sealants
4. Thermal insulating base
5. As cavity liner wherein cariostatic action is required
6. Core building material
7. Tunnel preparation
8. Sandwich technique
86. It is a brittle material with low tensile strength and
esthetically not as good as composites therefore cannot be
used in following situations.
- Class II cavity
- Class IV cavity
- Fractured incisal edge
- Lost cusps
- Restorations where esthetic is a prime consideration
87. MANIPULATION AND CLINICAL PROCEDURE:
1. Select the shade
2. Prepare the cavity required
If remaining dentine is less than 0.5mm provide
Ca hydroxide lining.
88. 3. Isolate the tooth from saliva
4. Apply surface conditioner which will improve
adhesion
5. Wash and gently dry the cavity without dehydrating
dentine
6. Reisolate and dry gently
7. Dispense cement on a glass slab or a mixing pad and
mix thoroughly for 30 sec with agate spatula using folding
method.
8. Convey the material to the cavity
89. 9. Place matrix if required matrix can be cellophane or
mylar strip. Allow cement to set
10. Remove the matrix and remove the excess by using
sharp surgical blade or knife and before it comes in
contact with moisture a protective barrier is applied
either with cavity varnish, petroleum jelly
Final polishing is postponed for 24hours but however modern
GIC’s can be finished and polished immediately after their
restorations.
93. Definition:
“A properly shaped piece of metal or non metal that
supports and gives form to the restoration during its
insertion and hardening”
94. Objectives:
1. To provide temporary wall of resistance during insertion
and hardening of the material.
2. To displace or retract gingiva and rubber dam
3. To achieve dryness and non-contamination of operating
field.
4. To maintain shape of the restoration till it sets
5. To resist and compensate for dimensional changes that
can occur during setting.
95. 6. To maintain natural contact and contours
7. To promote health of inter dental gingiva by preventing
overhanging restorations.
96. Ideal Requirements:
1. Should replace the missing wall temporarily
2. Should be rigid, flexible
3. Should have good stability
4. Should be easily applied and removed
5. Should be less cumbersome
6. Should be more comfortable for the patient
7. Should be reusable, sterilisable
97. 8. Inexpensive
9. Should not react or adhere to the restoration material
10. Should be small and handy so that access and visibility
is not affected.
11. Matrix band should extend about 1mm over marginal
ridge.
98. CLASSIFICATION:
I Based on area of restoration
a) Anterior – Cl III, Cl IV
b) Posterior – extended Cl I and Cl II
99. II Based on material used.
• Metallic – ex: stainless steel, copper and brass
• Non metallic ex: Celluloid and polyester
available as strips, open faced crowns (semicircular shape),
crown forms (surrounds full tooth)
100. III Based on method of retention
a) Without mechanical retainers
b) With mechanical retainers
Ex:
A] Black’s matrix and copper band supported by impression
compounds
B] Toffelmire, Ivory no. 1,8, Sequiland
101. IV Gilmore’s classification:
a) Custom made
Prepared by dentist or assistant suitable size matrix is cut
and impression compound placed in the place of wedge.
b) Mechanical
Toffelmire, sequiland, ivory no. 1 and 8
c) Miscellaneous
T-Band, soldered band, copper band, orthodontic band,
seamless band, blacks matrix.
104. Ivory No. 1
The band encircles one of posterior proximal surfaces therefore
indicated in unilateral Class II cavities.
Band is attached to the retainer through wedge shaped
projections which engage the tooth thru the embrasures of
unprepared surface.
105. Ivory No. 8:
Band encircles entire crown therefore indicated for bilateral
class II cavities,
Extended Class I and also for unilateral
Class II in which adjacent tooth is missing.
106. Tofflemire:
Also called as universal matrix
designed by B.R.Toffelmire.
Best used when 3 surfaces of
posterior teeth have been prepared.
107. Advantages:
- Convenience
- Placement on tooth buccal and lingual surface but
however lingual approach requires contra angle
design
- Retainer can be easily separated from band without
disturbing restoration.
108. Available in smaller sizes also so that it can be
comfortably used in deciduous dentition.
Bands available in 2 thickness 0.05 and 0.038mm
109. Blacks Matrix:
A metallic band is cut so that it will extend only slightly over
buccal and lingual surfaces of the tooth beyond buccal and
lingual extremities of cavity preparation.
This band is tied to the tooth with either a floss or wire at the
corners of gingival ends of band.
110. Auto matrix:
Retainers not used, designed for any tooth in the arch
regardless of its dimension. Best used in large class II
cavity.
Those replacing one or more cusps and
In pin amalgam restorations.
111. Advantages:
- Convenience
- Improved visibility due to absence of retainer
- Facial and lingual placement
- Reduced time for application
- Number of teeth can be restored in one visit
Disadvantages:
Expensive
113. Definition:
Material made up of either wood or synthetic material that is
used along with matrices during insertion and hardening of
plastic restoration material.
114. It is pointed,
Triangular in cross section
Base of cone is towards interdental papilla.
115. Classification:
I Based on material used:
- Wooden
- Plastic
II Based on availability
- Preformed
- Custom made – prepared by dentist / assistant
116. III Based on surface treatment:
- Medicated – coated with astringents
- Non – medicated
IV Based on material used
- Natural
- Synthetic
117. USES:
- Used along with matrix during insertion and
hardening of restoration material.
- It helps in close adaptability of matrix band to the
tooth thereby preventing restorative material getting
accumulated over the inter dental papilla which is
called overhang of restoration thereby preserving
health of periodontium.
118. - To immobilize matrix band
- To cause separation
- To retract gingiva and rubber dam
- To arrest bleeding temporarily
119. SEPERATORS:
- Tooth movement
- Objectives of separation
- Principles of separation
- Methods of separation
120. TOOTH MOVEMENT:
Act of separating / involved teeth from each other or
bringing them closer to each other or changing their
positions in one or more directions.
121. OBJECTIVES:
1. To move drifted, tilted and rotated teeth to their
physiologically indicated position to maintain natural
contacts and contours.
2. To close the space between the teeth which is not closed by
restorative methods.
122. 3. To move the teeth in order to improve the health of
periodontium.
4. To move the teeth apically (intrusion) and to move the teeth
incisally (occlusally) called extrusion to make them
restorable.
5. In order to expose the proximal surface to polish proximal
restorations.
6. To change the position of teeth from non-functional
position to a functional position.
123. 7. To detect proximal caries which is not detected by
conventional methods.
8. For easy placement of matrix band
9. To remove foreign bodies collected between teeth which
is not removed by floss, brush or explorer.
125. 1. Wedge principle:
Separation is achieved by placing pointed wedge shaped
device between the teeth and slowly inducing pressure.
Ex: Elliot’s separator, Wedges.
126. 2. Traction principle:
It is achieved by a mechanical device which engages
proximal surface of teeth to be separated by holding arms
and then separation is achieved.
Ex: Non interfering true separator, Ferrior double bow
separator.
128. Advantages of Rapid Separation:
Procedures is quick and stable
Disadvantages:
Chance of rupturing Periodontal Ligament fibers and it
will cause pain or soreness.
Examples:
Wedge, Ivory Separator, Elliot’s separator, Non interfering
true separator, Ferrior double bow separator.
129. Delayed Separation:
Advantages:
1. Less chances of tearing Periodontal ligament fibers
and doesn't cause much pain.
2. No mechanical device required.
3. Separators can be left in place for weeks together.
130. Disadvantages:
Procedure is time consuming and is not stable.
Examples:
Brass wire/ligature wire, heavy rubber dam material,
rubber elastics, oversized temporaries. Orthodontic
appliances.
139. Zones of dentinal caries
Effects of caries on pulp dentin organ
Diagnosis of deep carious lesions
Prognosis based on pulp exposure
Treatment.
140. Zones of Dentinal Caries:
1. Decayed zone
2. Septic zone
3. Dimineralized zone
4. Transparent zone – zone of dentinal sclerosis
5. Opaque zone
Zones of decay in Zones of decay in
acute decay. chronic decay.
141. Decayed zone:
Characterized by –
Complete absence of mineral structure
Organic matrix is completely decomposed
Collagen fibres are lost and if they are present they
have lost their cross striations and internal links
Significantly invaded by microorganisms and
plaque deposits.
142. Septic zone
- Called so because here you find highest population
of microorganisms, even though dentine is
demineralized its frame work structure can be
appreciated.
- Collagen fibers may have normal cross links but
internal links are lost.
143. - Dentinal tubules are widened and cavitated.
- Remaining mineral structure are deformed and
scattered irregularly.
- Color may range from light yellow to dark reddish
brown
144. Dimineralized Zone:
- Important diagnostically and therapeutically
- Dentinal matrix intact
- Collagen fibers normal
- Dentinal tubules normal dimensions
- Repair is taking place in the form of re-mineralization
145. Transparent Zone:
- Also called zone of dentinal sclerosis.
- Looks transparent in ground section but radio opaque
in radiographs.
- Here undisturbed repair mechanism is taking place.
- We can find few microorganisms.
- Slightly discoloured and very hard when compared to
normal dentine.
146. Opaque Zone:
It is characterized by intratubular fatty degeneration with
lipid deposits being precipitated from fatty degeneration of
the peripheral odontoblastic processes.
147. The maximum resistance to pulpal penetration occurs with
the arrival of the transparent and demineralized zone.
However, if the septic zone penetrates the pulp chamber, the
P-D organ will be unable to offer any resistance, and will
suffer complete collapse.
148. Caries can produce 3 types of irritation to underlying
pulp.
Biological – from microorganisms and their metabolites
Chemical – Acids released
Physico– Mechanical – due to reduced effective depth of pulp
dentine organ.
149. Severity of these irritation depends on
- Type of Decay
- Duration of Decay
- Depth of Involvement
- Number and pathogenecity of microorganisms
- Tooth resistance – depends on thickness of remaining
dentine, permeability and Ca++, F+ content.
150. Diagnosis and Prognosis of Deep Caries Lesions
1. Pain
2. Radiographs
Indicate
a. The proximity of carious lesions to pulp
chamber and root canal system
b. Any pulpal changes in the form of intra
pulpal and peripulpal calcification
c. The thickening of periodontal ligament with an
intact lamina dura etc.
151. 3. Pulp testing
a. Thermal
b. Electric pulp testing
4. Direct pulp exposure
5. Percussion
6. Type of dentine
153. Indirect pulp capping
Clinical Procedure
Decayed and infected zones and the external part of decalcified
zone are excavated using a spoon excavator.
154. All surrounding walls should be cleared of soft tooth
structure and debris to improve the stability of temporary
restoration.
Suitable capping material either calcium hydroxide or
ZnO liner is placed over the remaining dentine at the deepest
portion.
155. Then the cavity is sealed with either modified ZnOE Type III
or polycarboxylate cement or sometimes amalgam can be
used.
156. A radiograph is taken
Patient is recalled after 4-6wks if it is Calcium hydroxide and
6-8 wks if it is ZnO.
When the patient comes back a fresh radiograph is taken and
diagnostic information regarding pain is collected and
compared with pre treatment records.
157. If signs and symptoms and radiograph findings indicates no
degeneration in the pulp the pulp capping procedure is
considered as a clinical success and we can plan for
permanent restoration.
If repair has not taken place it is better to go in for RCT.
158. Direct pulp Capping
The tooth can be considered a candidate for DPC
a. There are no signs and symptoms of degeneration in PD
organ.
b. The exposure has small diameter relative to the pulp size
c. There is no hemorrhage from the exposure site, if there is
then blood should immediately coagulate in the form of
small button.
d. Dentine at periphery should be sound.
159. TREATMENT
All the procedures are same except few things.
1. The tooth to be operated should be isolated from saliva
application of rubber dam is mandatory.
160. 2. Cavity floor and exposed site should be gently washed and
irrigated with sterile water or saline solution.
3. Drying should be done with cotton pellet but never with
air from 3 way syringe patient is called after 6-8wks if it is
Ca OH and 8-9wks if it is ZnO.
165. Definition:
It is a compound with two or more distinctly different materials
the props of which are either superior or intermediate to those of
individual constituents.
Examples:
Natural: Tooth, Enamel and Dentine
167. Commonly used matrix:
Are monomers that are aromatic diacrylics examples:
BISGMA – Biphenol Glycidyl dimethacrylate
UEDMA – Urethene Dimethacrylate
TEGDMA – Tri ethylene Glycol Dimethacrylate
Inorganic Fillers are manufactured by grinding glass or quartz to
produce particles ranging from 0.1-100um. Silica particles small
as 0.04um called as micro fillers can also be produced by option
process incorporation of filler particles into the resin matrix will
significantly improve physical and therm expansion water
sorption polym. Shrinkage ___ reduced whereas compressive,
tensile it and modulus of elasticity are increased.
168. Coupling agents help in binding filler particle to the resin
matrix. This not only improves mechanical properties but also
provides hydrolytic elasticity i.e it presents water penetrating at
matrix filler interface.
Commonly used: Organosilanes
Class
I Based on filler particle size
Conventional – 8-12um
Small particle - 1-5um
Micro filled – 0.04-0.4um
Hybrid - 1um
169. II Based on polymerization mechanical
Chemically (or self activated)
Light activated
III Based on area of restorations
Anterior
Posterior
Polymerization mechanisms
Chemically
Available as 2 paste systems one or contains benz perox initiator
and the other contains tent amine activator.
When thus 2 or brought in contact free radicals are released and
polymerization begins.
170. Light:
Available as single paste system loaded in a syringe. Has a photo
initiator mol and amine activator. When it is exposed to the
light of correct wavelength photo initiator gets excited reacts
with activator, free radicals are released and polymerization
starts has also range between 400-500nm.
Visible light of the spectrum is used to cure the composites. It
is produced by a hallogen bulbwhich is delivered to
the required area by a fibre optic disadvatgaes of using U.V
light.
1. Limited depth of curing
2. Polymerization shrinkage
3. Occlar hazards
171. Indications and Contraindications:
1. From Class I to Class IV cavities except high stress bearing
areas like extensive Class II and extended Class I’s
2. Class V cavities in which control of saliva can be achieved.
3. In restoration of developmental defects like enamel
hypoplasia, densein dente microdontia, malpositioned teeth
4. Non carious lesions like cervical abrasions erosions.
5. Treatment of fracture incisal edge
6. Splinting of luxated teeth.
172. 7. Closing diastema (less than 1mm)
8. Veneering of discoloured teeth.
9. Veneering of metallic restorations
10. Core buildings
11. Composite Inlays
12. Repair of old composite restorations
