All details about the dental polymer Components and Composition Molecular Weight Polydispersity Structure Of Polymer Mechanical And Physical Properties Of Polymer, Rheometric Properties Solvation and dissolution Properties Thermal Properties Requirement Of Dental Resins Dental Use Of Resins

1. DENTAL
POLYMER
PRESENTED BY:-
DHANANJAY SINGH

2. DENTALPOLYMER
Content:-
* Introduction
* Components and Composition
* Molecular Weight
* Polydispersity
* Structure Of Polymer
* Mechanical And Physical Properties Of Polymer
* Rheometric Properties

3. * Solvation and dissolution Properties
* Thermal Properties
* Requirement Of Dental Resins
* Dental Use Of Resins

4. INTRODUCTION
.Polymers are formed through Chemical
Reaction that convert large no. of Low
Molecular weight molecules called Monomer or
‘Mer’ into Large very high Molecular weight
Long chain Macromolecules.

5. Resins:-These are Composition of
either monomer or Macromolecules blended
with other Components.

6. On The Basis Of Type Of Mer
Units-
Polymers are of twoTypes!
 HOMOPOLYMER
Polymers Containg same type of Monomer
unit.
 COPOLYMER
Polymers Containing 2 or more types of
Monomer Unit.

7. Copolymer Structure.
 Copolymer can be further divided into 3Types!
 Random Copolymer
ABBAAABBBAABABABABBBBAAAAAA
 Block Copolymer
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 Branched/ Grafted Copolymer
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| |
B B
B B
B B

9. COMPONENTS AND COMPOSITION
Backbone of Chain
Extent Of Branching
Cross Linking and
Molecular weight
Determines the Property of a Polymer.

10. .
 BACKBONE-
Polymers are consist of very large macromolecules and that
they are Chain like structure often called Backbone.
In addition to C-chain macromolecules may also consist of
Inorganic network ex- SiO2 in glass Silicate Ceramics.
 CHAIN BRANCHING-
Branching is analogous to extra arms growing out of Polymer
chain.
 CROSS LINKING-
Cross Linking forms bridges between chains and dramatically
increase Molecular weight, consequently physical and
mechanical properties may vary.

11. Molecular Weight
• Molecular weight of polymer molecule equals the
molecular weight of various mers multiplied by
number of mers unit.
• They may range from thousands to millions of units
depending on preparation condition.

12. Two types of average molecular
weight are commonly used:-
> Based on average number of mer units in a chain (Mn)
> Based on molecular weight of average chain (Mw)
> Mw is always greater than Mn except when all
molecules are of same length ;thenMn=Mw

13. Polydispersity
* Ratio of Mw/Mn is called polydispersity.
* It is the measure of range and distribution
of chain sizes.
* Polymers of high polydispersity will began
to melt at lower temperature and heavily
larger temperature range of melting.

14. Effect of polymer chain length, branching and crosslinking on mechanical
and physical properties.Rigidity,strenght and melting temperature
increase as polymer chain length grows and molecular weight increases.

15. Structure Of Polymer
There are three basic structures:-
Linear polymer :-
 In these polymers monomers are linked with each other and
form a long straight chain.
 These chains has no any side changes.
 Their molecules are closely packed and have high density,
tensile strength, and melting point.

16. Branched polymer
 IN these polymer branching occurs by the
replacement of a subunit.
 Branching may results from the formation of carbon-
carbon or various type of other bonds.
 Branching some times occurs spontaneously during
synthesis of polymer

17. Crosslinked polymer
Crosslinking forms bridges between chains and
dramatically increase molecular weight.
Consequently physical and mechanical property vary
with the composition and extent of crosslinking for a
given polymer system.
The three dimensional network of crosslinked polymers
increase rigidity and resistance to solvents.

19. MechanicalAndPhysical
PropertyOfPolymer
These properties are grouped into four categories:-
>Mechanical Properties
>Rheometric Properties
>Solvation And Dissolution Properties
>Thermal Properties

20. Mechanical Properties
Applied forces produce stresses within polymer
that cause materials to deform (i.e. undergo strain)
via:-
Plastic strain- Irreversible deformation that
cannot be recovered and result in a new permanent
shape as the result of slippage(flow) among polymer
chain.

21. Elastic strain- Irreversible deformation
and will be completely recovered when the
stress is eliminated as a result polymer chain
uncoiling and then recoiling.

22. Visco Elastic- Combination of both elastic and plastic
deformation, but only elastic portion is recovered
when the stress is reduced.

23. Rheometric Properties
 The rheometry,or flow behavior of solid polymer
involves a combination of elastic and plastic
deformation followed by elastic recovery after stress is
removed.
 The chain length,number of crosslinks,temprature,
and the rate of force application determine which type
of behavior dominates.

24. Solvation And Dissolution Properties
*Polymers are usually slow to dissolve and clearly either
soluble or insoluble in a particular liquid.
*Solvation characteristic is sensitive to
* Molecular Weight -> Molecular weight increases solvation
decreases
* Polydispersity –> (Mw/Mn) increases salvation decreases
* Cross linking –> Cross linking increases , dissolution decreases
* Chain Branching –> Branching increases , dissolution
decreases

25. Thermal Properties
* The physical properties of polymer are
influenced by change in temperature.
* Higher the temperature, the softer and
weaker the polymers become.

26. Based on their thermal behavior they are
divided into :-
* Thermoplastic polymer:-
*They undergo a reversible change.
*These are rasins that can be repeatedly softened and
molded under heat and pressure without chemical change
occurring. They are soluble in organic solvents.
*Example- polymethyl methacrylate , polyvinyl
acrylics

27. * Thermosetting polymer:-
*They undergo irreversible change when heated.
* These are the rasins which can be molded only once.
*They are set when heated
*This cannot be softened by reheating
*They are insoluble in organic solvent.
* Example- Bakelite , Phenol Formaldehyde

29. RequirementsOfDentalResins
 It should be tasteless, non-toxic and non-irritant to
the oral tissue
 Be esthetically satisfactory
 Be dimensionally stable
 Have enough strength ,resilience and abrasion
resistance
 Be insoluble and impermeable to oral fluids
 Be easy to fabricate and repair
 Have coefficient of thermal expansion which match
that of tooth structure

30. Dental Usesof resin
* Prosthodontics:-
> Denture base and teeth
> Soft liners
> Custom trays
* Operative Dentistry:-
> Glass- ionomer cements
> Cavity fillings
> Pit and fissure sealants
* Orthodontics:-
> Brackets
> Bracket bonding resins and cement
> Spacers
*

31. * Endodontics:-
>Gutta-percha points
>Root canal Sealants
>Rubber dams
* Equipments:-
>Mixing bowls
>Mouth guard
>Protective Eyewear