Protecting the Pulp

Question 1

what does the pulp need protection from?

Answer 1

galvanic shock, chemical attack, thermal discomfort

Question 2

where does chemical attack come from?

Answer 2

acids in dentine bonding agents, acrylic resin, constituents of certain restorative materials, residual acid - acidogenic bacteria

Question 3

where does thermal discomfort come from?

Answer 3

polymerisation exotherm of some restorative materials, light curing units, hot/cold food and drink, cavity prep

Question 4

where does galvanic shock come from?

Answer 4

restoration of disimilar materials in close proximity, set up an electrolyte cell, galvanic pain

Question 5

how does cavity prep cause insult?

Answer 5

insult = increased inflammatory cell infiltrate = smear layer

Question 6

what does the smear layer do?

Answer 6

occludes dentinal tubules with bacteria from cavity, collagen and hydroxyapatite

Question 7

what would a material need to be ideal for pulp protection?

Answer 7

non toxic, obtundant, widely compatible with range of restorative materials, radiopaque, strength to withstand restoration, thermal/electrical insulation, good coronal seal, bacteriostatic, non irritant

Question 8

what material is calcium hydroxide? advantages

Answer 8

dycal
high ph - bacteriocidal, high ph - initially irritates - reactionary dentine
thermal/electrical insulator, radiopaque, good compatibilty,

Question 9

calcium hydroxide disadvantages?

Answer 9

not adhesive enough - no coronal seal,

insufficient strength for condensation

Question 10

zinc polycarboxylate? advantages?

Answer 10

poly F
high molecular weight - reduced penetration to tubules only mildly irritant
fluoride - bacteriostatic
sufficient strength for restoration
insulating
good compatibility

Question 11

zinc oxide and eugenol?

Answer 11

kalzinol
slight irritancy to pulp
zinc - bacteriocidal and radiopaque
insulator
if reinforced - withstands
very obtundant
no coronal seal

Question 12

zinc phosphate

Answer 12

low ph - low MW, highly irritant to pulp 
insulator
zinc - bacteriocidal and radiopaque
comaptible 
not obtundant
good strength
no coronal seal

Question 13

glass polyalkenoates

Answer 13

GI/Vitrabond
low ph, high mw mild irritation
F - bacteriostatic
insulator, good strength, good seal, compatible, chemical cured/reinforced +resin = VLC

Question 14

when to line a cavity?

Answer 14

if >2mm line

if

Question 15

how to avoid pulpal exposure in deep caries

Answer 15

avoid exposure - bacteria will penetrate chamber
discomfort when caries - within 0.5mm of pulp
indirect/direct pulp cap
stepwise excavation

Question 16

what is an indirect pulp cap?

Answer 16

cavity has extended to within 0.5mm of pulp
hard setting CaOh to deepest part of cavity
may be covered and resin modified with Gi
restored as normal

Question 17

what is a direct pulp cap?

Answer 17

exposed pulp covered by capping material

CaOH/mineral trioxide aggregate

Question 18

what is the criteria for a direct pulp cap?

Answer 18

no pain from tooth, vital tooth, no evidence of perriradicular pathology, pulp pink/healthy, no bleeding

Question 19

what is the technique of a direct pulp cap?

Answer 19

dry + cotton wool
material applied to exposure and other areas close to pulp
resin modified GI on top
tooth restored as normal and monitored

Question 20

what is a stepwise excavation

Answer 20

when stained soft dentine is left in the base of the cavity but ADJ is clear

Question 21

technique of a stepwise excavation?

Answer 21

seal over entire base of cavity where caries remains with dycal
dress + GI cement
remove GI 6-12 months later

Question 22

what should be found at the end of stepwise excavation?

Answer 22

base should be stained but now firm, CaOH has arrested

now restore with permanent material