Clinical Composite

Question 1

factors to consider regarding use of composite

Answer 1

tooth biology
material science
interfaces
marginal seal
manipulation
polymerisation

Question 2

why is the ADJ important when using composite

Answer 2

caries left at the ADJ will result in unsupported enamel and early breakdown of the restoration margin if micro leakage occurs

marginal integrity is compromised

Question 3

what happens if there is poor enamel preparation at the margin

Answer 3

• the composite dimension will change
• etch is stronger than the interstitial enamel strength leading to enamel failure and micro leakage

Question 4

which kind of dentine is favourable for hybrid layer creation

Answer 4

primary dentine as it is less mineralised and therefore the tubules are more open

Question 5

why is tertiary dentine unfavourable for hybrid layer creation

Answer 5

it has an irregular structure

Question 6

why is deeper dentine unideal for hybrid layer formation

Answer 6

it is wetter, meaning the moisture content is higher which the methacrylate will struggle to bond to
it is also more mineralised and has more tubules

Question 7

what are the characteristics of older dentine

Answer 7

fewer tubules, more mineralised and occluded tubules

Question 8

what are the characteristics of reactive dentine

Answer 8

occluded tubules, more mineralised and irregular tubules

Question 9

how does poor quality dentine allow adhesion

Answer 9

through ion exchange

Question 10

why are the linings in dentine relative to consider before bonding

Answer 10

can provide reason for placement, impact bonding, contaminate enamel
there are risks if micro leakage occurs and can lead to secondary caries

Question 11

what are the most common issues with clinical composite

Answer 11

cavity preparation
bonding
contacts
placement
countering contraction stresses

Question 12

to understand tooth tissue for bonding, which elements should be understood

Answer 12

material properties
cavity design
matrices
manipulation
configuration factor
polymerisation contraction stress

Question 13

what is CF

Answer 13

cavity configuration factor - the ratio of bonded to unbonded surfaces, which is important for composite restorations
It’s used to predict shrinkage stress in the materials used for composite resin restorations. A higher C-factor indicates a higher risk of polymerization shrinkage stress, which can lead to problems like: Marginal gaps, Post-operative sensitivity, and Restoration failure

Question 14

how does cavity configuration factor relate to polymerisation contractions stress

Answer 14

low CF means reduced polymerisation contraction stress

Question 15

is bond strength greater than to etched enamel or to dentine

Answer 15

enamel

Question 16

what is plasticity

Answer 16

a property of a material to undergo a non reversible change of shape in response to an applied force (polymerisation)

Question 17

what is deformation

Answer 17

a change in shape due to an applied force (contraction)

Question 18

what is polymerisation contraction

Answer 18

plastic deformation

Question 19

draw the stress strain diagram

Answer 19

Question 20

why is it important to build up composite

Answer 20

reduces chance of pain after restoration by reducing shrinkage - larger lumps shrink more

Question 21

what do contoured bands allow

Answer 21

positioning of the contact better than flat bands

Question 22

list the clinical procedure to a filling

Answer 22

etch
prime
bond
placement
characterisation
finish

Question 23

why does enamel need longer etch time than dentine

Answer 23

because it is more mineralised

Question 24

list the stages to a filling in detail

Answer 24

enamel etch for 10s
moist surfaces
dentine primer
adhesive application
at this point consider the need for flowable composite to mediate contraction stresses on interface and to achieve optimal adaption to non load bearing margins
1st increment on the floor only
successive increments touching as few surfaces as possible
the final increments should not join enamel margins, this is to give correct morphology as there are normally occlusal fissures

Question 25

what is the minimum intensity required to adequately cure 1.5mm to 2mm of composite resin

Answer 25

in between 280 and 300 mW/cm2
check the light regularly

Question 26

what are the different curing regimes

Answer 26

soft start
ramp
pulse
boost
delayed curing

Question 27

why is it important that curing lights aren’t high intensity

Answer 27

the composite shrinks

Question 28

function of high power curing light

Answer 28

fast curing

Question 29

function of low power curing light

Answer 29

close to pulp curing

Question 30

function of soft start curing

Answer 30

polymerisation with reduced contraction stress

Question 31

mW/cm2 value for low power curing lights

Answer 31

650

Question 32

mW/cm2 value for high power curing lights

Answer 32

1,200

Question 33

what is the main reason for reduced shrinkage stress

Answer 33

decreased final conversion

Question 34

what is shrinkage direction determined by

Answer 34

bonded surfaces and free surfaces

Question 35

when does composite shrink toward the light

Answer 35

if the bonding fails

Question 36

what is the value for the halogen like emission spectrum that polymerises all materials

Answer 36

380-515 nm

Question 37

what are the steps to placing composite increments

Answer 37

sectional matrix and wedge in place
enamel etch
dentine and enamel etch
wash and remove excess moisture
bond placement and cure
flowable composite placement and cure
occlusal floor only composite increment, cure
mesio lingual wall, 1st increment placement to midpoint of contact, cure
mesiobuccal wall, second increment placement to midpoint of contact, cure
matrix removed and contact and gingival floor are checked
disto buccal occlusal increment placed and cured
mesiobuccal occlusal increment placed and cured
distolingual occlusal increment placed and cured
mesiolingual occlusal increment placed and cured
marginal finish and occlusal checked
final polish and surface seal
completed restoration