Manipulation of composite Flashcards
What are the steps of application of resin composite restorations?
- selection of resin composite type
- shade selection
- isolation of the operating field
- matricing and wedging
- application of adhesive system
- application of liner (if needed)
- packing and curing of composite
- finishing and polishing
What do filler size and filler loading determine?
properties of resin composite and
its ability to provide proper mechanical support, form, contour and maintain proper surface polish
What re hybrid composites suitable for?
all indications of posterior teeth and
in stress bearing areas because of its high strength properties, best
mechanical support and provide proper contact and contour
What are packable composites used for?
provide better contact and contour in posterior teeth
What are microfilled composites used for?
provide a long-lasting smooth finish and better esthetic in anterior teeth
What are microfilled and flowable composites used for?
low modulus of elasticity –> flexible enough –> withstand flexure of the tooth under stresses –> used in class V
What are nano composites used for?
considered as universal composite that can be used in all indications of anterior and posterior teeth with high mechanical properties & high polishability for esthetics
What do we need in class 4 and what type of composite can be used?
- high mechanical properties are needed for occlusion and high
polishability is needed for esthetics - nano composite as universal composite can b used
- hybrid composite for the palatal part and then veneer it with
microfilled composite for esthetics
What circumstances should be present to select a suitable shade using the shade guide?
- under good illumination of white day light and operatory light
- should be done under wet condition and before isolation
- using the shade buttons after wetting them
- teeth must be wet as dehydrated teeth becomes lighter in shade
- the shade buttons must be made of the same composite that will be used
What should be done if shade of composite cannot be easily determined?
- mock-up
- selected shade is placed in the cavity, light cured, contoured, finished & polished –> accurate assessment of the selected shade and shape of composite
- then the cured composite is easily removed by hand instrument as it is
unbounded to the tooth structures
Why is isolation from moisture essential?
- for bonding to tooth structure as well as during the insertion of composite
- moisture contamination can cause
failure of bonding and decrease the mechanical properties of the composite restoration
What is the most accurate method to isolate the cavity?
rubber dam
What are other isolation techniques?
cotton rolls
When are retraction cords used and why are they used?
cervical margins to avoid seepage of gingival fluid at the gingival seat
Which classes use Mylar matrx strip?
class 3 and 4
What is the importance of wedging?
to stabilize the matrix and allow for some teeth separation to ensure a tight contact
Why should th matrix be placed before etching and application of adhesive?
to protect adjacent tooth
Which class c?an have a celluloid crown former?
class 4 restorations
What can be used for cervical restorations?
class V clear matrix
Which system is used for posterior proximal restorations: sectional or tofflemire?
sectional matrix system is preferred over the tofflemire matrix system in
composite restorations as it provides proper separation by the ring and the sectional matrix bands are precontoured for better contact and contour
How is adhesive system applied?
- adhesive system is selected
- the manufacturer’s instructions should be strictly followed
- for enamel, using etch & rinse adhesive is recommended –> Chalky white appearance
- for dentin, self-etch approach is recommended
- for the best adhesion to both enamel and dentin we should follow the selective etch technique
- phosphoric acid etch should be applied to enamel only and then washed with water
- spreading of the adhesive layer should be done either with brush-thinning or light air-thinning
- adhesive layer should be cured before application of resin composite
- oxygen inhibits polymerization –> the top 15 microns of the adhesive will not polymerize, providing sufficient chemical co-polymerization with the resin
composite
How is liner applied?
A layer of flowable composite might be used under packable composites to increase the adaptation and to absorb stresses
How is packing and curing of resin composite done?
- handling of composite material is not easy as it is not a condensable
material - teflon or gold-plated packing instruments should be used to avoid sticking to composite
- dragging of the composites towards the walls and margins of the cavity with fine brushes is done before curing to increase its adaptation
What are the advantages of visible light-cured over chemical-cured composite?
- command setting (unlimited working time)
- no air bubbles as it is one paste (no mixing)
- improved color stability
What are the disadvantages of light cured composites?
- direct prolonged eye exposure to light source can cause retinal damage
- heat generation from the light source could cause pulpal irritation
What are the techniques for packing of resin composite?
- bulk technique
- incremental packing technique
What is bulk technique?
- composite is applied in one single bulk inside the cavity
- this technique is used with chemical-cured composites
- with light-cured composites, it is used in small non-deep cavities (depth not exceed 2mm for complete polymerization)
What is incremental packing technique?
- used with light-cured composites only.
- restorations are placed in successive small increments (not more than 2mm) and each light-cured independently
What are the advantages of incremental packing technique?
- total polymerization shrinkage is reduced because each increment compensates for the shrinkage of the previous one
- the direction of polymerization shrinkage could be controlled
What are the steps of finishing and polishing?
- gross finishing can be performed with 30- to 40-fluted carbide burs or
fine and micro-fine diamond points - carbide burs and diamond points for finishing of composite
- no. 12 Scalpel blade is very useful and effective in removing composite
flashes - finishing and polishing discs (e.g., soflex discs) (coarse, medium, fine
and extra-fine grits) can be used at low speed - finishing & polishing spiral wheels
- proximal finishing strips are also available for finishing of the proximal portion of a composite restoration
- finishing and polishing can also be done with special rubber tips,
points, cups and brushes
Why is there VC with retraction cord sometimes?
reduce bleeding if it occurs
What should be accompanied with cotton rolls?
saliva ejector or high volume suction
Is tofflemire matrix system flat?
yes
Is sectional matrix system flat?
no, it is contoured
What is the name of the technique used for class 2?
egg shell technique (build proximal walls then class 1)
What is the name of the technique used for class 4?
palatal index technique (build palatal wall first)
