Manipulation of composite

Question 1

What are the steps of application of resin composite restorations?

Answer 1

• 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

Question 2

What do filler size and filler loading determine?

Answer 2

properties of resin composite and
its ability to provide proper mechanical support, form, contour and maintain proper surface polish

Question 3

What re hybrid composites suitable for?

Answer 3

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

Question 4

What are packable composites used for?

Answer 4

provide better contact and contour in posterior teeth

Question 5

What are microfilled composites used for?

Answer 5

provide a long-lasting smooth finish and better esthetic in anterior teeth

Question 6

What are microfilled and flowable composites used for?

Answer 6

low modulus of elasticity –> flexible enough –> withstand flexure of the tooth under stresses –> used in class V

Question 7

What are nano composites used for?

Answer 7

considered as universal composite that can be used in all indications of anterior and posterior teeth with high mechanical properties & high polishability for esthetics

Question 8

What do we need in class 4 and what type of composite can be used?

Answer 8

• 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

Question 9

What circumstances should be present to select a suitable shade using the shade guide?

Answer 9

• 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

Question 10

What should be done if shade of composite cannot be easily determined?

Answer 10

• 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

Question 11

Why is isolation from moisture essential?

Answer 11

• 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

Question 12

What is the most accurate method to isolate the cavity?

Answer 12

rubber dam

Question 13

What are other isolation techniques?

Answer 13

cotton rolls

Question 14

When are retraction cords used and why are they used?

Answer 14

cervical margins to avoid seepage of gingival fluid at the gingival seat

Question 15

Which classes use Mylar matrx strip?

Answer 15

class 3 and 4

Question 16

What is the importance of wedging?

Answer 16

to stabilize the matrix and allow for some teeth separation to ensure a tight contact

Question 17

Why should th matrix be placed before etching and application of adhesive?

Answer 17

to protect adjacent tooth

Question 18

Which class c?an have a celluloid crown former?

Answer 18

class 4 restorations

Question 19

What can be used for cervical restorations?

Answer 19

class V clear matrix

Question 20

Which system is used for posterior proximal restorations: sectional or tofflemire?

Answer 20

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

Question 21

How is adhesive system applied?

Answer 21

• 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

Question 22

How is liner applied?

Answer 22

A layer of flowable composite might be used under packable composites to increase the adaptation and to absorb stresses

Question 23

How is packing and curing of resin composite done?

Answer 23

• 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

Question 24

What are the advantages of visible light-cured over chemical-cured composite?

Answer 24

• command setting (unlimited working time)
• no air bubbles as it is one paste (no mixing)
• improved color stability

Question 25

What are the disadvantages of light cured composites?

Answer 25

• direct prolonged eye exposure to light source can cause retinal damage
• heat generation from the light source could cause pulpal irritation

Question 26

What are the techniques for packing of resin composite?

Answer 26

• bulk technique
• incremental packing technique

Question 27

What is bulk technique?

Answer 27

• 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)

Question 28

What is incremental packing technique?

Answer 28

• used with light-cured composites only.
• restorations are placed in successive small increments (not more than 2mm) and each light-cured independently

Question 29

What are the advantages of incremental packing technique?

Answer 29

• total polymerization shrinkage is reduced because each increment compensates for the shrinkage of the previous one
• the direction of polymerization shrinkage could be controlled

Question 30

What are the steps of finishing and polishing?

Answer 30

• 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

Question 31

Why is there VC with retraction cord sometimes?

Answer 31

reduce bleeding if it occurs

Question 32

What should be accompanied with cotton rolls?

Answer 32

saliva ejector or high volume suction

Question 33

Is tofflemire matrix system flat?

Answer 33

yes

Question 34

Is sectional matrix system flat?

Answer 34

no, it is contoured

Question 35

What is the name of the technique used for class 2?

Answer 35

egg shell technique (build proximal walls then class 1)

Question 36

What is the name of the technique used for class 4?

Answer 36

palatal index technique (build palatal wall first)