Tissue management and impression making

By Dr.Swathi Pai on Monday 12 January 2009 with 0 comments



The goal of tissue displacement is to achieve space for impression materials both vertically and laterally.

3 types of retraction cords: plain, braided, or knitted

Chemicals used in cords:

-epinephrine

-potassium aluminum sulfate (ALUM)

-aluminum chloride (Hemodent)

-ferric sulfate

-zinc chloride

-tetrahydrozoline

Epinephrine (0.1%-0.8%):

Creates local vasoconstriction

A 1 inch of cord with 1.0mg of epinephrine contains 2.5x the max dose for healthy patients and 12x the dose recommended for cardiac patients

Contraindications for epinephrine use in cord: hx of cardiovascular disease, hyperthyroidism, allergy to epinephrine

Use caution with patients taking: Rauwolfia compounds (old HTN med.), ganglionic blockers and HTN treated with guanethidine

Signs of epinephrine syndrome: tachycardia, increase in respirations, nervousness,increase in B.P., post op. depression---these symptoms will appear after the cord has been in place for a few minutes or shortly after it is removed.

If you must use epinephrine, 0.1% is better than 8%.

ALUM (potassium aluminum sulfate):

Only slightly less effective than epinephrine at shrinking tissues

Will get 0.1mm permanent loss of crestal tissue

Hemodent (aluminum chloride):5-10%:

Conc in excess of 10% will cause local tissue destruction

A 10min application is usually sufficient

Will get 0.1mm permanent loss of crestal tissue

There are no major contraindications and minimal systemic effects

Ferric sulfate (13.3%):

A.k.a.---cut-trol, astringent

Very good for hemostasis

Does not noticeably traumatize tissues and heal more rapidly than hemodent

Temporarily discolors tissues for 1-2 days

Provides tissue displacement for at least 30min

Zinc chloride (Bitartrate):8% & 40%:

Tissue displacement equal to epinephrine

Tissue necrosis is high

NOT RECOMMENDED FOR USE

Tetrahydrozoline (visine, afrin, murine plus, neosynephrine)

A sympathomimetic amine that produces vasoconstriction with minimal side effects

Category: Prosthodontics Notes

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