A short review of literature about dental composites with a brief discussion about the recent advancements

1. Classification and
Composition

2. Definition
• A composite is a material made from two or
more constituent materials with significantly
different physical or chemical properties that,
when combined, produce a material with
characteristics different from the individual
components.
• The individual components remain separate
and distinct within the finished structure.
https://en.wikipedia.org/wiki/Composite_material

3. • Matrix
• Filler
• Coupling Agent
• Initiators and
accelerators
• Pigments

4. Resin Matrix
•Bis-GMA (Bisphenol-A Glyceril Methacrylate)
•UDMA (Urethane Dimethacylate)
•TEGDMA (Triethylene Glycol Dimethacrylate)
If the composite is made up of just the resin
matrix, it is called Unfilled Resin
Note: Although Bis-GMA is more properly called an oligomer, we
shall use the term monomer when referring to it.

5. A B
C
Structure of (A) Methyl methacrylate,
(B) Triethylene Glycol Dimethacrylate,
and (C) Bis-GMA.

6. • The notable features of Dr. Bowen’s oligomer are polar
side groups that increase chain to chain hydrogen
bonding and two reactive C=C groups.
• Since each C=C group can participate in the formation
of a growing polymer chain, the oligomer is called
bifunctional.
• Bifunctional monomers and oligomers result in cross-
linking and greatly improve the strength of the
resulting polymer

7. Filler
• •Silica particles
• •Quartz
• •Glass ( Ba, Sr, Zr)

8. Size
• Determines the surface
smoothness.
• Larger particles =
rougher surface
Content (percentage)
• As the filler content
increases, the resin content
decreases. Therefore,
polymerization shrinkage
decreases, and the
coefficient of thermal
expansion becomes more
like that of tooth structure.
Hardness and abrasion
resistance increase as well

9. • There is a difference between filler content as measured by
weight and by volume. Because the filler phase is much
denser than the resin phase, the volume percentage is
typically 10% to 15% lower than the weight percentage.
• Manufacturers like to report the weight percentage because
it is higher. Physical properties are determined by the
volume percentage, so it is the favorite of scientists.

10. Filler Particle Size
Scanning electron micrographs of two dental composites (B
and D) and their filler particles (A and C).
The smaller filler particles result in composite restorations
with a smoother surface. (Courtesy of BISCO, Inc.)

11. Filler percentage
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0% 28% 37% 48% 53% 62% 70%
Fracturetoughness
FRACTURE TOUGHNESS
Filler by volume

12. Coupling Agent
• The coupling agent
couples, or transfers,
stress from the
relatively weak matrix
to the relatively strong
filler. Dental composites use
ceramic filler particles coated with
silane coupling agents.
• Silane coupling agents work a bit
like soap; they have a different
chemical group at each end of the
molecule.
• Silane coupling agents are
molecules that react with the
polymer matrix at one end and with
the ceramic filler at the other end,
as illustrated

13. Coupling Agent
• The coupling agent couples, or
transfers, stress from the relatively
weak matrix to the relatively strong
filler. Dental
composites use
ceramic filler
particles coated with
silane coupling
agents.
• Silane coupling agents work a bit like
soap; they have a different chemical
group at each end of the molecule.
• Silane coupling agents are molecules
that react with the polymer matrix at
one end and with the ceramic filler at
the other end, as illustrated

14. Coupling Agent
• The coupling agent couples, or transfers, stress from the relatively
weak matrix to the relatively strong filler. Dental composites use
ceramic filler particles coated with silane coupling agents.
• Silane coupling agents
work a bit like soap;
they have a different
chemical group at each
end of the molecule.
• Silane coupling agents are molecules
that react with the polymer matrix at
one end and with the ceramic filler at
the other end, as illustrated

15. • The coupling agent couples, or transfers, stress from the relatively
weak matrix to the relatively strong filler. Dental composites use
ceramic filler particles coated with silane coupling agents.
• Silane coupling agents
work a bit like soap;
they have a different
chemical group at each
end of the molecule.
• Silane coupling agents are molecules
that react with the polymer matrix at
one end and with the ceramic filler at
the other end, as illustrated
Coupling Agent

16. Coupling Agent
• The coupling agent couples, or transfers,
stress from the relatively weak matrix to the
relatively strong filler. Dental composites use
ceramic filler particles coated with silane
coupling agents.
• Silane coupling agents work a bit like soap;
they have a different chemical group at each
end of the molecule.
• Silane coupling
agents are molecules
that react with the
polymer matrix at
one end and with the
ceramic filler at the
other end, as
illustrated

17. Optical Modifiers/Pigments
• Provides the opacity or translucency
needed to make the composites similar
to the natural tooth tissue

20. Metal oxide particles as radio-opacifiers:
• Titanium dioxide
• Aluminum oxide

21. Clinical Aspect
• Configuration factor (C-factor):
refers to the number of bonded
surfaces to the number of un-
bonded surfaces in a dental
restoration.
𝐍𝐨. 𝐨𝐟 𝐒𝐮𝐫𝐟𝐚𝐜𝐞𝐬 𝐨𝐟 𝐜𝐚𝐯𝐢𝐭𝐲 (𝐁𝐨𝐧𝐝𝐞𝐝)
𝐍𝐨. 𝐨𝐟 𝐂𝐨𝐦𝐩𝐨𝐬𝐢𝐭𝐞 𝐬𝐮𝐫𝐟𝐚𝐜𝐞𝐬 (𝐔𝐧𝐛𝐨𝐧𝐝𝐞𝐝)

22. • Configuration factor (C-factor):
refers to the number of bonded
surfaces to the number of un-
bonded surfaces in a dental
restoration.
𝐍𝐨. 𝐨𝐟 𝐒𝐮𝐫𝐟𝐚𝐜𝐞𝐬 𝐨𝐟 𝐜𝐚𝐯𝐢𝐭𝐲 (𝐁𝐨𝐧𝐝𝐞𝐝)
𝐍𝐨. 𝐨𝐟 𝐂𝐨𝐦𝐩𝐨𝐬𝐢𝐭𝐞 𝐬𝐮𝐫𝐟𝐚𝐜𝐞𝐬 (𝐔𝐧𝐛𝐨𝐧𝐝𝐞𝐝)

23. C-factor
• With an increasing C factor the
developing polymerization shrinkage of
bonded composites increases too
(Feilzer et al. 1987).
• The developing polymerization shrinkage
in a composite generate stress on the
bonded interface that are in competition
with the developing bond strength of the
setting restorative (Adhesive) to the
cavity surfaces, which may result in
(partial) debonding, marginal leakage
and post-operative pain

24. • Polymerization shrinkage can be minimized by
using:
• "soft-start" polymerization instead
of high-intensity light curing
• incremental layering to reduce the effects of
polymerization shrinkage; and
• a stress-breaking liner, such as filled adhesive,
flowable composite, or resin-modified glass
ionomers
• the application of non or low shrinking restorative
materials
C-factor

25. • Polymerization shrinkage can be minimized by using:
• "soft-start" polymerization instead of high-intensity
light curing
• incremental layering to
reduce the effects of
polymerization
shrinkage; and a stress-
breaking liner, such as
filled adhesive, flowable
composite, or resin-
modified glass ionomers
• the application of non or low shrinking restorative
materials
C-factor

26. • Polymerization shrinkage can be minimized by
using:
• "soft-start" polymerization instead of high-intensity
light curing
• incremental layering to
reduce the effects of
polymerization
shrinkage; and a stress-
breaking liner, such as
filled adhesive, flowable
composite, or resin-
modified glass ionomers
• the application of non or low shrinking restorative
materials
C-factor

27. • Polymerization shrinkage can be minimized by using:
• "soft-start" polymerization instead of high-intensity
light curing
• incremental layering to
reduce the effects of
polymerization
shrinkage; and a stress-
breaking liner, such as
filled adhesive, flowable
composite, or resin-
modified glass ionomers
• the application of non or low shrinking restorative
materials
C-factor

28. • Polymerization shrinkage can be minimized by using:
• "soft-start" polymerization instead of high-intensity
light curing
• incremental layering to reduce the effects of
polymerization shrinkage; and a stress-breaking
liner, such as filled adhesive, flowable composite, or
resin-modified glass ionomers
• The application
of non or low
shrinking
restorative
materials
C-factor

29. 1. Macro filled
2. Micro filled
3. Hybrid (including nano)
4. Special indications

31. Macro/Micro/Hybrid

32. Macro filled Composites
• The first type (1960s) Macrofilled composite.
• The filler type Quartz
• Particle sizes of 10 to 25 μm.
• Filler content is 70% to 80% by weight.

33. • The large size of the filler
particles results in a
restoration that feels
rough to the dental
explorer (Roughness)
• Plaque accumulation and
staining is greater with
this type
• Macrofills have little
clinical importance at this
time except that some
Orthodontists still use
them

34. • late 1970s Microfilled
• Particle size (0.03–0.5 μm).
• Microfill composites polish very
smooth and lustrous and the
surface appearance is very
similar to enamel.
• The filler type is fused silica.
• Low percentage filler (40–50%).
• The surface area of the very
small filler particles requires
much more resin to wet the
surface of the filler particles.
This high resin content results
in an increased coefficient of
thermal expansion and lower
strength.

35. • The polymerization shrinkage of microfilled composites is less than
expected based on the total resin content. Some (or all) of the filler
particles are actually “composite filler particles”. The resin of these
“composite filler particles” has already been polymerized. Therefore,
this resin cannot polymerize and does not increase polymerization
shrinkage. It does increase the coefficient of thermal expansion.
• Additional uncured matrix components are combined with the
“composite filler particle” to make the microfilled composite paste.

36. Hybrid Composites
• Late 1980s
• These composites are strong and
polish well.
• Their filler content is 75% to 80%
by weight.
• The filler particles (0.5 to 1 μm)
size, wider range of particle sizes
(0.1–3 μm) that’s why called
hybrid (or blended).

37. • Hybrid composites are very popular; their
strength and abrasion resistance are
acceptable for small to medium Class I and II
restorations. Their surface finish is nearly as
good as that of microfills; thus, they are also
used for Class III and IV restorations.
Hybrid Composites

38. • Hybrid composites are very popular; their
strength and abrasion resistance are
acceptable for small to medium Class I and II
restorations. Their surface finish is nearly as
good as that of microfills; thus, they are also
used for Class III and IV restorations.
Hybrid Composites

39. • Manufacturers’ improved the clinical
performance of composite materials.
• They continue to maximize the amount of
filler present by controlling the particle size
and distribution.
• The average particle size has decreased
and nanosized particles have been added.
• Nano-sized particles are approximately 100
times smaller than the thickness of a
human hair. The results are slight
improvements in strength and
polymerization shrinkage.

40. • Hybrid composites currently on the market are a
result of manufacturers’ efforts to improve the
clinical performance of composite materials.
They continue to maximize the amount of filler
present by controlling the particle size and
distribution. The average particle size has
decreased and nanosized particles have been
added. Nano-sized particles are approximately
100 times smaller than the thickness of a human
hair. The results are slight improvements in
strength and polymerization shrinkage. The most
notable improvement is the smooth surface of
modern well-polished composite materials. These
materials have largely replaced microfilled
compositions

42. Filtek P90 / Silorane
• The low-shrinking Filtek P90 Low
Shrink Posterior Restorative is
based on the new ring-opening
silorane chemistry, which is a
totally new class of compounds for
use in dentistry.

45. Special Use Composite Materials
flow
into the cavity preparation
because of their Lower
viscosity.

46. Special Use Composite Materials

47. Special Use Composite Materials
• A weaker
• Less Abrasion-resistant
• Typically used as the Initial increment of a
composite restoration and then covered with
a hybrid material.

48. Special Use Composite Materials
• Condensable composites (Packable)
• To make placement easier.
• In general, condensable composites have a filler particle feature that
inhibits the filler particles from sliding by one another.
• A “thicker, stiffer feel” results, and the manufacturers call these
products condensable. Clinical research has shown these materials
with a different “feel” are not an improvement over hybrid composite
materials; most performed poorly and few are still on the market.

49. Special Use Composite Materials
• Condensable composites (Packable)
• To make placement easier.
• In general, condensable composites have a
filler particle feature that inhibits the filler
particles from sliding by one another.
• A “thicker, stiffer feel” results, and the manufacturers call these
products condensable. Clinical research has shown these materials
with a different “feel” are not an improvement over hybrid composite
materials; most performed poorly and few are still on the market.

50. Special Use Composite Materials
• Condensable composites (Packable)
• To make placement easier.
• In general, condensable composites have a filler particle feature that
inhibits the filler particles from sliding by one another.
• A “thicker, stiffer feel” results, and the
manufacturers call these products
condensable. Clinical research has shown
these materials with a different “feel” are not
an improvement over hybrid composite
materials; most performed poorly and few are
still on the market.

51. Special Use Composite Materials
• Bulkfill Composites
• A 4 mm depth of cure – reducing the need for
incremental layering and risk of
contamination.
• A flowable viscosity for easy adaptation– less
instrument manipulation.

52. Special Use Composite Materials
• Bulkfill Composites
• A 4 mm depth of cure – reducing the need for
incremental layering and risk of
contamination.
• A flowable viscosity for easy adaptation– less
instrument manipulation.

53. • Bulk Fill Flowable Restorative is
especially suited for the following
Indications:
• Base under Class I and Class II
direct restorations
• Liner under direct restorative
materials
• Pit and fissure sealant

57. • INDICATIONS: Fiber reinforced
composite is suitable for use as the
reinforcing material for direct composite
restorations, especially in large
posterior cavities, for example:
1. Cavities including 3 surfaces or more
2. Cavities with missing cusps (Deep)
3. Endodontically treated teeth
(Surrounding a fiber post)
4. Cavities after Amalgam replacement
5. Cavities where Onlays & Inlays would
also be indicated

58. Clinical Hint
Optionally, apply first a
thin layer of flowable
composite to the cavity
floor before the
application of everX
Posterior. Place the
everX Posterior on top
of the flowable
composite and pack it
in the cavity.

59. Note: everX Posterior should
always be covered with a
layer of light-cured universal
restorative composite, for
sufficient wear resistance

60. • CONTRAINDICATIONS
1. Do not use for pulp capping.
2. At least one horizontal
dimension of the cavity should
exceed 3 mm.
3. In rare cases the product may
cause sensitivity in some
people. If any such reactions
are experienced, discontinue
the use of the product and refer
to a physician.
4. The product is not suitable
for patients with a history of
hypersensitivity to methacrylate
monomers.
5. Do not use as final
approximal and surface
composite layer.

64. Resources/Referrences
• Clinical Aspects of dental materials 4th edition by Marcia
Gladwin and Michael Bagby.
• “Composite resin” presentation on www.slideshare.net by
Wilda Bianca.
• “Polymerization shrinkage of composite materials” on
www.slideshare.net by Mohammed H. Nabulsi BDS, MFDS,
RCS. (Ireland).
• “Stresses in adhesive restorations” dental courses by indian
dental academy channel on www.slideshare.net
• www.gc-dental.com
• www.dentsplymea.com
• A review of polymerization shrinkage stress: current
techniques for posterior resin restorations (Article) By Luca
Giachetti Md,DMD. Daniele Scaminaci Russo DDS. Claudia
Bambi DDS. Romano Grandini Md, DMD.
• P90 study booklet by Alfred Viehbeck global technical
director at 3M ESPE.