Protecting the Pulp Flashcards
what does the pulp need protection from?
galvanic shock, chemical attack, thermal discomfort
where does chemical attack come from?
acids in dentine bonding agents, acrylic resin, constituents of certain restorative materials, residual acid - acidogenic bacteria
where does thermal discomfort come from?
polymerisation exotherm of some restorative materials, light curing units, hot/cold food and drink, cavity prep
where does galvanic shock come from?
restoration of disimilar materials in close proximity, set up an electrolyte cell, galvanic pain
how does cavity prep cause insult?
insult = increased inflammatory cell infiltrate = smear layer
what does the smear layer do?
occludes dentinal tubules with bacteria from cavity, collagen and hydroxyapatite
what would a material need to be ideal for pulp protection?
non toxic, obtundant, widely compatible with range of restorative materials, radiopaque, strength to withstand restoration, thermal/electrical insulation, good coronal seal, bacteriostatic, non irritant
what material is calcium hydroxide? advantages
dycal
high ph - bacteriocidal, high ph - initially irritates - reactionary dentine
thermal/electrical insulator, radiopaque, good compatibilty,
calcium hydroxide disadvantages?
not adhesive enough - no coronal seal,
insufficient strength for condensation
zinc polycarboxylate? advantages?
poly F high molecular weight - reduced penetration to tubules only mildly irritant fluoride - bacteriostatic sufficient strength for restoration insulating good compatibility
zinc oxide and eugenol?
kalzinol slight irritancy to pulp zinc - bacteriocidal and radiopaque insulator if reinforced - withstands very obtundant no coronal seal
zinc phosphate
low ph - low MW, highly irritant to pulp insulator zinc - bacteriocidal and radiopaque comaptible not obtundant good strength no coronal seal
glass polyalkenoates
GI/Vitrabond
low ph, high mw mild irritation
F - bacteriostatic
insulator, good strength, good seal, compatible, chemical cured/reinforced +resin = VLC
when to line a cavity?
if >2mm line
if
how to avoid pulpal exposure in deep caries
avoid exposure - bacteria will penetrate chamber
discomfort when caries - within 0.5mm of pulp
indirect/direct pulp cap
stepwise excavation
what is an indirect pulp cap?
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
what is a direct pulp cap?
exposed pulp covered by capping material
CaOH/mineral trioxide aggregate
what is the criteria for a direct pulp cap?
no pain from tooth, vital tooth, no evidence of perriradicular pathology, pulp pink/healthy, no bleeding
what is the technique of a direct pulp cap?
dry + cotton wool
material applied to exposure and other areas close to pulp
resin modified GI on top
tooth restored as normal and monitored
what is a stepwise excavation
when stained soft dentine is left in the base of the cavity but ADJ is clear
technique of a stepwise excavation?
seal over entire base of cavity where caries remains with dycal
dress + GI cement
remove GI 6-12 months later
what should be found at the end of stepwise excavation?
base should be stained but now firm, CaOH has arrested
now restore with permanent material
