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Composite materials of chemical curing..pdf
1. Lesson 8. Composite materials of chemical curing.
Classification, composition, properties, indications for use, methods of representatives,
representatives.
Rinat Bayburin
Department of Therapeutic Dentistry
Krasnoyarsk State Medical University
3. By particle size of filler
• macro-filled (particle size - 8-12 microns and more)
• minifilled (particle size - 1-5 microns)
• microfilled (particle size - 0.04-0.4 microns)
• macrohybrid (mixture of particles of various sizes: 0.04-0.1 and up to 8-12 microns)
• microhybrid (mixture of particles of various sizes: 0.04-0.1 and up to 1-5 microns)
• hybrid totally executed composites (mixture of particles of various sizes: 8-5 microns; 1-5
microns; 0.01-0.1 microns)
• nanohybrid (mixture of particles ranging in size from 0.004 to 3 microns)
5. By the degree of filling with inorganic filler
• highly filled, more than 70% by weight.
They have sufficient strength and are intended for the restoration of posterior teeth.
• medium filled 66-75% by weight.
• weakly filled 66% or less.
These composites are fluid, highly elastic, and are used to restore anterior teeth and Class
V cavities.
6. By curing method
1. Chemical curing - type I.
2. Light-cured - Type II.
3. Dual curing:
• light + chemical;
• light + heat.
10. Polymer matrix of composites (organic matrix)
The organic polymer matrix is the basis of composites and determines
• plastic,
• its adhesive properties,
• biocompatibility,
• influences strength,
• color stability,
• the degree of polymerisation of the composite.
The amount of shrinkage and other characteristics depend on the volume of organic matter.
11. Polymer matrix of composites (organic matrix)
Bisphenol Glycidyl Methacrylate (Bis-GMA)
• forms the basis of almost all modern dental composites,
• the monomer has a high molecular weight,
• is able to form very long chains that "cover" filler particles,
• hardens at room temperature and in the presence of a catalyst in just 3
minutes,
• polymerization shrinkage is 5%.
12. Polymer matrix of composites (organic matrix)
The polymer matrix also contains:
• Polymerization inhibitor - to increase the working time with the material and lengthen the shelf
life.
• Catalyst - to start polymerization.
• Additional catalyst — to improve the polymerization process (chemically cured composites only).
• Activator (photoinitiator of polymerization) - to start the polymerization process (only in light-
curing composites).
• UV absorber - to improve color stability, reduce discoloration of the material when exposed to
sunlight.
13. Filler (dispersed phase)
Inorganic (mineral) filler is the second important component of modern composites. The filler determines such
properties of composites as:
• strength,
• shrinkage,
• water absorption,
• abrasion resistance,
• radiopacity,
• color stability.
Fused and crystalline quartz, aluminosilicate and borosilicate glass, various modifications of silicon dioxide, aerosil,
pre-polymerized crushed composite and other substances are used as fillers.
14. Filler (dispersed phase)
The particle size of the filler can vary from 0.01 to 100 microns. The larger these
particles, the more it can be introduced into the composite, the higher the
strength of the material, the less shrinkage with constant plasticity.
However, large particles form a rough surface devoid of shine and contribute to
increased abrasion of the filling.
15. Filler (dispersed phase)
Small particles allow the composite to be polished, more abrasion resistant. It is
impossible to introduce a large amount of fine filler into the composition of the
material, since small particles have a large surface area.
In materials with small filler particles, basic physical parameters such as strength,
water absorption, and color stability also deteriorate. To maintain plasticity and
strength, all filler particles must be "enveloped" in an organic matrix.
16. Filler (dispersed phase)
Due to the presence of a large amount of filler, an improvement in the properties of composite
plastics is achieved, namely:
• polymerization shrinkage decreases (up to 0.5-0.7%);
• deformation of the polymer organic matrix is prevented;
• the coefficient of thermal expansion decreases;
• water sorption decreases;
• the hardness of the material, its abrasion and resistance to stress increases;
• the aesthetic properties of the material are improved, since the filler has a refractive index and
translucency close to the corresponding indicators of tooth enamel.
17. Surfactants (silanes, or intermolecular phase)
Silane is an organosilicon compound, a bipolar coupling agent
(dimethyldichlorosilane). It forms a chemical bond with an inorganic filler and with
an organic matrix, due to which the structure of the composite becomes
homogeneous, its strength and wear resistance increase, and water absorption
decreases.
19. Macro-filled composite materials
The composition includes inorganic fillers with a particle size of 8 to 12 microns and more.
Properties:
• high aesthetics,
• good marginal fit,
• high physical and chemical properties.
But fillings made of macrophilic composites are poorly polished, their surface remains
rough and, as a rule, changes in color over time. The roughness of the filling is
accompanied by pronounced abrasion of the antagonist tooth and the filling itself.
20. Macro-filled composite materials
Positive properties of macro-filled composites:
• sufficient strength;
• acceptable optical properties;
• radiopacity.
The disadvantages of macro-filled composites are associated with the significant size
of the inorganic filler particles and their irregular shape. These materials are difficult to
polish. Roughness (micropores) remains on the surface of the filling, as the softer
organic matrix is removed, exposing large particles of inorganic filler. The porosity of the
filling surface contributes to the deposition of plaque, food pigments, which leads to a
change in the color of the filling and the loss of individual particles of inorganic filler.
21. Macro-filled composites are unsuitable for esthetic restorations as
they lack abrasion resistance, color stability and polishability.
22. Indications for the use of macro-filled composites
• For filling cavities of I, II, V class;
• For filling the anterior group of teeth, if an aesthetic effect is not required.
24. Mini-filled composite materials
• Are characterized by slightly smaller filler particle sizes - 1-5 microns; particle
sizes 3-5 microns are more common. By reducing the size of the filler particles,
their total surface area increases. Therefore, in mini-filled composites, the
percentage (by weight and volume) of inorganic filler decreases.
• They are used for the restoration of chewing (small cavities) and anterior group
of teeth;
• Due to insufficient strength and color stability, they were not widely used.
25. Mini-filled composite materials
• Minifilled composites are similar in their properties to macrofilled composites,
but due to a decrease in the size of filler particles, they are better polished and
have lower hardness.
• On average, the volumetric content of the filler is about 50-55%.
27. Microfilled composites
They contain an average of 37% filler by volume with a particle size of 0.01 - 0.4 microns.
Positive properties of microfilled composites:
• good polish to a mirror finish;
• durability of a glossy surface;
• high color fastness;
• good aesthetic qualities. Availability of a wide range of material colors. They have, as a rule,
shades: dentin (opaque), enamel, tooth necks, cutting (incisal) edges, bleached teeth.
• low abrasive wear.
28. Microfilled composites
Negative properties:
• non-radiopacity;
• insufficient mechanical strength. The large total surface area of the filler
particles requires a large amount of organic matrix for binding, therefore the
strength of the material decreases;
• high coefficient of thermal expansion.
29. Microfilled composites
Indications for the use of microfilled materials:
• for filling cavities of III, V class.
• filling of defects in non-carious lesions of teeth (enamel erosion, hypoplasia,
wedge-shaped defects, etc.).
• сlass IV aesthetic filling.
31. Macrohybrid composite materials
• To increase the strength of microfilled composites, large particles of inorganic
filler were introduced into them. Such materials are called hybrid materials.
• In the first hybrids, a combination of microparticles less than 1 micron in size
and macroparticles larger than 8-10 microns of an inorganic filler —
macrohybrid materials — were used.
• Despite the improvement in the quality of these materials, the fillings of them
had a rough surface, changed after some time in color (due to the absorption
of food pigments) and caused abrasion of the antagonist teeth.
33. Microhybrid composite materials
The combination of micro and miniparticles (1-2 microns) of an inorganic filler
turned out to be more successful, which made it possible to create a new type -
microhybrid composite materials, which now dominate in the filling and
restoration of anterior and posterior teeth.
34. Microhybrid composite materials
Positive properties of microhybrid composites:
• good aesthetic qualities; wide range of material color shades.
• good physical and mechanical properties; Microhybrids are usually highly filled
materials - up to 75-80 by weight. They are very resistant to fracture in clinical
situations where tooth restorations are exposed to significant chewing
pressure. High resistance to compression, bending, low water absorption and
coefficient of thermal expansion (close in value to the hard tissues of the teeth).
35. Microhybrid composite materials
Positive properties of microhybrid composites:
• good polishability; These hybrid composites polish better than macrophilic materials, but
less efficiently than microfilic materials. With a fairly long polishing, the surface of the
restoration made of them can be brought to a good mirror shine, which makes it possible
to use this type of composites for restoring anterior teeth
• good quality of the surface of the seal; The use of newer types of acrylic resins with
improved physicochemical characteristics allows microhybrids to achieve very high (up to
10-15 years) color stability of a restoration or filling.
• universal use.
• radiopacity.
36. Microhybrid composite materials
Negative properties:
• imperfect surface quality (worse than microfilled);
• insufficient strength and spatial stability;
• high polymerization shrinkage (from 3% to 5%);
• the complexity of clinical application (layer-by-layer application of the material,
directed polymerization).
37. Microhybrid composite materials
Indications for the use of microhybrid composites:
• filling of cavities of all five classes;
• production of vestibular aesthetic adhesive veneers (veneers);
• repairing chipped ceramic crowns.
38. Representatives:
• Tetric (Vivadent),
• Charisma (Heraeus Kulzer),
• Brilliant (Coltene),
• Te Econom (Vivadent),
• Herculite XRV (Kerr),
• Prodigy (Kerr),
• Valux Plus (3M),
• Prisma TPH (Dentsply),
• Degufil Metra ( Degussa),
• Unirest (Stomadent)
• and many others.
39. Totally executed hybrid composites
• These are composites with a high degree of filling (80 - 90%), due to the
composition of filler particles of different sizes: macro-, mini- and
microparticles. This allows you to achieve even better physical and mechanical
properties and polishability of the material.
• The high viscosity of the material makes it possible to carry out high-quality
plastic processing, formation and condensation of the material with a high
degree of control and without the formation of pores in the restoration.
40. Totally executed hybrid composites
• have a modified organic matrix.
• low shrinkage (1.7 - 2.0%), which makes it possible to abandon the method of
directional polymerization.
• most materials have the property of a "chameleon", i.e. the ability of the filling
to acquire the optical color of the tooth.
• well polished.
Indications for use: filling of cavities of I - V classes.
42. Nanohybrid composites
The first representative of nanocomposites is Filtek TM Supreme.
• This material contains a spherical silicon-zirconium filler with a size of 5 to 75
nm. Some nanoscale particles are combined into complexes - nanoclusters.
Their size varies from 0.6 to 1.4 microns, which allows filling the material up to
78.5% by weight. This gives the material high strength.
The same group of materials includes: Grandio (VOСО), Premise (Kerr), etc.
43. Nanohybrid composites
Grandio (VOCO) is a universal nanocomposite. It has 14
shades on the Vita scale. Contains two types of fillers: ceramic
glass with a particle size of 0.5-1 microns and nanoparticles of
silicon oxide with a size of 20-60 nm. The fullness by weight is
87%. It has low shrinkage (1.57%), is durable and has high
aesthetics.
Premise (Kerr) is a universal nanocomposite material with three
types of filler particles: 0.02 and 0.4 microns in size, as well as
a pre-polymerized PPF filler; has a filling of 84%, which in turn
reduced the polymerization shrinkage to low values - 1.6%.
45. Chemical curing composites are two-component systems:
• One component contains a chemical activator - tertiary aromatic amines, the
other - a chemical polymerization initiator - benzoyl peroxide. When mixed, free
radicals are formed in the polymerization reaction.
Release form:
• paste-paste,
• powder - liquid.
46. Chemical curing composites
The main form of production of modern composite materials "paste - paste".
The composite kit includes:
• two pastes - basic and catalytic,
• adhesive system - base and catalytic fluids,
• enamel etching gel,
• accessories: mixing pad, plastic spatulas, brushes and brush holder, material
colors.
47. Basic properties of chemically cured composite materials:
Positive properties:
• high physical and mechanical properties (especially for macro-filled and hybrid composites),
• good aesthetic properties (for microfilled and hybrid),
• good adhesion to hard tooth tissues and marginal adhesion of the filling when using adhesive systems,
• chemical resistance in the oral cavity,
• uniformity of polymerization;
• ease of use;
• high speed of restoration manufacturing;
48. Basic properties of chemically cured composite materials:
Negative properties:
• require mixing of components, as a result of which porosity of the material is possible;
• difficulty in preparation and work: it is difficult to calculate the amount of material,
• necessary for restoration; composites change viscosity during operation;
• the restoration darkens over time ("amine staining" due to unreacted activators
remaining in the material);
• low wear resistance;
• relatively low aesthetic properties.
49. Chemical curing composites:
• Compolite Plus (SuperDent),
• Composite (Alpha-Dent),
• Evicrol Anterior (Spova Dental),
• Core-Max II (Dentsply),
• Talan (Stomadent, Compodent-M (Stomakhim),
• Degufill SC (Degussa),
• Compolux (Septodont),
• Evicrol Posterior (Spova Dental),
• Charisma PPF (Kultzer)
• and etc.
50. Stages of work with composites of chemical curing
1. Professional oral hygiene - thorough treatment of the tooth surface, removal of tartar, soft
plaque.
2. Selection of the desired shade of filling material.
3. Anesthesia.
4. Dissection of a carious cavity.
5. Medication of the cavity.
6. Drying and degreasing the cavity after isolating from saliva.
7. Applying an insulating pad for moderate caries, a curative and insulating pad for deep caries.
51. Stages of work with composites of chemical curing
8. Enamel etching. 37-50% phosphoric acid gel is applied. After 30-40 seconds, it is
thoroughly washed off. The etching time is equal to the rinsing time.
9. Drying the cavity with an air jet of a pistol.
10.Application of enamel adhesive (if included). Apply with a brush, spread with a
stream of air.
11.Filling. The filling material is applied in one portion. A filling is being formed.
12.Grinding and polishing fillings.
13.Coating the tooth with a fluoride varnish.
52. General contraindications to the use of composite materials:
• unsatisfactory oral hygiene;
• bruxism;
• pathological bite;
• increased abrasion of hard tissues of teeth;
• pathology of periodontal tissues;
• subgingival cavity;
• occupational hazards.
