Types of Composites

DLA 1201, exam 4

1. Types of Composites Flowable, Sealants, Bulk-fill, packable, core build-up, provisional

2. Flowable Composites These composites flow readily and can be delivered directly into cavity preparations by small needle cannulas attached to the syringes in which they are packaged. The material has low viscosity, which means it flows and adapts well to cavity walls and flows into microscopic irregularities created by diamond and carbide burs. 2

3. Flowable Composites Flowables are well suited for conservative dentistry (preventive resin restorations, AKA sealants). Some dentist use flowables instead of conventional sealant material. Low-viscosity, light-cured resins Lightly (~40%) or heavily (~70%) filled The materials that are lightly filled shrink more when polymerized, wear more readily, and are weaker . Initially, the particle size was in the range of those for hybrid composites. However, Nanosized fillers are also being used in the flowable composites.

4. Flowable Composites Useful as liners in large cavity preparations, because they adapt to the preparation better than more viscous materials such as hybrid and packable composites. They have a low elastic modulus Allows them to cushion stresses created by polymerization shrinkage or heavy occlusal loads when they are used as an intermediate layer under hybrid or packable composites. The lower the elastic modulus, the more flexible the material; the higher the elastic modulus, the stiffer the material. Flowable composites are useful for restoration of class V Noncarious lesions caused by toothbrush abrasion, abrasion, acid erosion, or abfraction (from occlusal stresses, such as bruxing (grinding of teeth), which lead to flexing of the tooth). https://youtu.be/- agAsNscOqA

5. Flowable Composites Lightly filled flowable composites: shrink more when polymerized (about 4-6%) than the hybrid composites (<3%) Wear more readily Are weaker They are being improved to make them stronger and more durable with less shrinkage. Some manufacturers have developed self-adhesive flowable composites that bond directly to dentin without the need for a separate bonding agent, since the bonding agent is incorporated into the composite.

6. Pit and Fissure Sealants Low-viscosity resins Vary in their filler content from no filler to more heavily filled resins. Heavily filled are essentially flowable composites. They are used to prevent dental caries in pits and fissures of teeth. 6

7. Bulk-Fill Composites Developed to speed up placement process of composite restoration The challenges of the bulk-fill composites are to have a depth of cure that permits increments of 4mm or more , to not shrink excessively, to flow well into all aspects of the preparation without voids, to have acceptable physical properties, and to be esthetic with good polishability .

8. Bulk-Fill Composites To achieve a greater depth of cure, manufacturers have increased the translucency , or reduced the amount of filler, or changed the chemical makeup to enhance polymerization when curing is initiated. Available in two consistencies: Flowable and Viscous nanohybrids Flowables adapt well to the internal portions of the preparations, whereas viscous nanohybrids must be carefully manipulated into the line angles and undercut areas. https:// youtu.be/avLE33WfncE

9. Bulk-Fill Composites Has limitations on its use in the proximal box of class II restorations, because the depth of the box is often 6 to 7mm, far beyond curing capability. More than one increment (40-60 second) should be used in the proximal box Polymerization shrinkage has been reduced by adding special modifiers that relieve stress in the restoration during curing or by adjusting the size, number, and composition of the filler. The shrinkage for bulk-fill composites is in the range found with other high-viscosity composites (1.3 to 2.4%) Bulk-fill with increased translucency or less filler may need to be covered with a Nanohybrid or nanocompisite in order to achieve esthetics and wear resistance. Shade selection is limited Only 4 shades to choose from

10. Bulk-Fill Composites To achieve the desired depth of cure (4mm or more), the curing light must be used for the recommended time. The curing light output should be tested periodically with a radiometer to make sure that the output of the unit has not deteriorated, The light tip needs to be free of residual composite debris that could limit the transmission of light Light exposure times for fast-curing lights such as an argon laser or plasma arc curing light, typically suggested 5-10 seconds for curing, may be too short to adequately cure bulk composite to this depth, and time must be extended.

11. Packable Composites Highly viscous microhybrids The high volume of filler particles gives this material a stiff consistency. Makes it less likely to stick to composite instrument Posterior teeth restoration Class I and II restorations Because they are stronger and more wear resistant 11

12. Core Buildup Composites Core buildup composites are heavily filled composites used in badly broken-down teeth needing crowns. They replace missing tooth structure lost from dental caries of tooth fracture so that there is adequate structure to retain a crown. Core composites are strong and can be bonded to tooth structure to minimize bacterial leakage and increase retention. https:// youtu.be/LPxvVqJGxpI 12

13. Core Buildup Composite BU materials are often pigmented so that they can be easily identified. The figure shows composite core material with color contrasting to the tooth structure for easy identification during crown preparation. Can be: Light-cured Self-cured Dual-cured https:// youtu.be/m7aDoKNSzec

14. Core Buildup Composite Dentin-colored core materials are used when all-ceramic crowns are to be placed. Amalgam would create an esthetically unacceptable dark discoloration under the all-ceramic crown, as light passes through the porcelain and reflect off the amalgam.

15. Core Buildup Composite Strong and can be bonded to the tooth structure to minimize bacterial leakage and increase retention. Mechanical retention is still necessary, because bonding alone is not strong enough to resist forces placed on the crown. The materials are packaged in: A mpoules, commonly called “compules” Syringes with automixing tips Cartridges with automixing tips similar to impression materials.

16. Provisional Restorative Composites Provisional crowns and bridges hold the prepared teeth in position so they do not drift and change their proximal contact position or occlusion relation with the opposing teeth.

17. Provisional Restorative Composites Provisional restorations have the following functions: Provide esthetics in the smile zone Maintain proper speech Allow proper function for chewing Maintain proper form for oral hygiene Protect exposed dentin Provide good marginal seal

18. Provisional Restorative Composites Until the last decade, acrylic resins (polymethylmethacrylates) were widely used for the construction of provisional onlays, crowns and bridges. They are Inexpensive, but they also: Exhibit wear Shrink upon polymerization Release heat upon polymerization Have an unpleasant odor and taste Can discolor Messy to use

19. Provisional Restorative Composites Newer provisional materials made with bis-acrylics and rubberized urethane have improved the physical and mechanical properties. Bis-acryl composite resin is easy to handle and comes in a two-tube cartridge with automixing tips. It can be dispensed directly into the matrix (or carrier) for a provisional restoration. Exhibits very little shrinkage on curing Radiopaque More brittle than acrylic resin and tends to break more easily with longer-span bridge, though..

20. Provisional Restorative Composites Rubberized urethane is a new type of provisional composite resin that is similar to bis-acrylic in its setting characteristic, radiopacity, and curing shrinkage. However, many of its properties have been improved because of the addition of rubber molecule to the diurethane resin. It has an increased flexural strength and is less brittle, so it hold sup better for longer-span bridges. It is more impact resistant under occlusal loading an dis more flexible Easy to insert and remove

21. Provisional Restorative Composites Both bis-acrylic and rubberized urethane materials are available in several shades. They are dual-cured materials, so they can be chemically cured (about 90-120 seconds) If a clear matrix is used, they can be light cured too! Why only if a clear matrix is used?? They can be repaired easily with flowable composite to add to contact areas and margins. Can be shaped and adjusted with acrylic burs, abrasive discs and finishing diamonds. They can be polished with abrasive rubber points or wheels and polishing pastes or painted with resin glaze to provide a smooth, shiny surface. https:// youtu.be/U-eVSg1Ty8U?t=21

22. Four Classification Methods for Composites Classification Method Microfill Microhybrid Nanocomposite Flowable Hyrbid Filler amount (Volume%) 30-50 60-70 78 30-55 Particle Size (µm) Macro (10-100) Fine(0.1-10 Micro (0.01-0.1) Nano ( 0.001-0.01) Matrix Composition Bis-GMA Bis-GMA or UDMA Silorane (Low Shrinkage) Bis-GMA or UDMA Polymerization Method Self- or Light-cured Self- or Light-cured Light-cured Light-cured

23. General Information Some composites give off heat when cured. Exothermic reaction To avoid shrinkage, composite resins should be placed into the preparation in small increments Bulk-filled composites being the exception.

24. 7 different types of composites https:// youtu.be/eLbqjxFaKaQ