Retraction cord/Bite Reg

Function of cord?

Used for temporary tissue displacement during crown and bridge procedures

3 things retraction cord does

Widen sulcus for impression material

Expose prep margin

Obtain accurate impression of tooth prep up to epithelial tissue

When retraction cord is indicated?

AFTER the preparation but BEFORE impressions

Name 5 different types of retraction cord

Twisted cord

Untwisted cord

Braided cotton cord

Plain non-impregnated cord

Impregnated cord

How are the size and thickness of cord determined

According to the size of the sulcus

Larger number = Larger cord

True

Why is cord pre-treated with chemical agent?

To control bleeding & for shrinkage of the tissue

Epinephrine in regards to cord is used for what?

Faster blood clotting and reduced bleeding in the preparation

What happens when Epinephrine is placed in the sulcus?

Rapidly absorbed into blood stream

When would Aluminum Chloride be indicated?

When Epinephrine cannot be used due to cardiovascular side effects which AC doesn’t have

Type of astringent mainly used for cord packing

Aluminum chloride

4 astringents used when epinephrine is NOT indicated

Aluminum chloride

Zinc chloride

Ferric sulfate

Aluminum sulfate

Contradictions of epinephrine impregnated cord

Epi cord can cause and increase in blood pressure and pulse

patients with a history of what would have contraindications for epi?

Cardiovascular disease**

Hypertension

Hyperthyroidism

Diabetes

what are the 4 methods of retraction

Surgical

Electrosurgery

Chemical

Mechanical

Surgical retraction

Scalpel/surgical knife used to cut away tissue

Electrosurgery/Cautery

Burning away tissue tab or tissue overgrowth

Chemical retraction

Cord soaked in chemical to reduce bleeding

Mechanical retraction

Placement of temp crowns an have patient return after several days for impression

What can be used to pack cord?

Plastic instrument/packing instrument

Most important thing to do PRIOR to procedure?

Check patients health history for contraindications

If there is excessive bleeding PRIOR to cord placement what should be done?

Delay impression

What can be done to keep area dry before packing cord

Area packed with cotton rolls and dried with air water syringe

How can the operator’s measure the cord

Using the pinky finger as measuring guide to cut piece long enough to fit circumference of tooth 1-1.5 inches

How many cords is used for traditional cord packing

One cord

When placing cord, where is it place?

Margin of prep

Where is cord packed down too?

Around cervical area to epithelial attachment

What can be done during cord placement to prevent area to be missing

Overlap cord at starting point

What surface should the cord end?

Buccal surface

For what kind of restorations would cord be placed?

Class II MOD (only M/D)

Class V

When is 2 cords indicated

When the sulcus is wider and deeper

Would the smaller or larger cord be placed first

Smaller

Which cord is taken out before impression is taken?

Larger top cord

Which cord is removed after the impression

Smaller second cord

What can cause damage of epithelial attachment

Too much pressure during the cord placement

How long can cord be left in place for

5-7 mins depending on chemical

What should be done if bleeding occurs AFTER PACKING

Place medicated cotton pellets

What procedures would require retraction

PFM/ Gold crown

Class V

Laminated veneers

Inlays

What would not require retraction

MOD amalgam

Denture

Stainless steel crown

In which direction is cord packed?

Clockwise

Which direction is cord removed

Counterclockwise

Which instrument is used to removed cord

College piers

Bite Registration

Impression used to establish the correct occlusal relationship of the upper and lower casts so they can be mounted on the articulator

Centric occlusion

When jaws are closed in postion to produce maximal stable contact between max and max teeth

Occlusal registration

Record of this relationship

Base plate wax

“Pink wax” used to take bite registration

What are the 4 types of bite registration material

Bite wax w/ foil for reinforcement **

Zinc oxide Eugenio registration paste

Silicone

Vinyl polysiloxane***

Open bite technique

Material directly excluded into occlusal surfaces of mandibular teeth

Open bite technique

Material mixed on pad/dispensed from extruded gun and placed into tray and patient closes into occlusion

Closed mouth impressions

Tripple tray impression”

Material is mixed and injected into special mesh tray on both sides and tray is inserted in patients mouth and instructed to close

Closed bite registration

Patient instructed to close/place tongue against teeth, material extruded from gun onto area requiring registration

Why is patient instructed to bite down into normal occlusion?

Allow operator to observe position of the arches

Allow patient to comprehend what the operator needs to achieve

How can the patient establish proper occlusion

Roll the tip of tongue on the palate as far back as possible

What wax can be used for wax registration

Impression wax

Base plate wax

for wax registration, if wax extends beyond last tooth what can be done with the excess?

Cut the excess with a lab knife

For bite registration, what do all have in common?

All require patient to bite into centric occlusion

Contradictions for eugenol in the paste

Bad taste/odor

Sticks in mouth

Irritates muscosa

Brittle causing fracture/disorientation

Advantages of zinc oxide eugenic bite

Fast setting

No resistance to bite

What should be known when mixing silicone putty

Use bare hands to knead, do not wear latex gloves

Advantage to vinyl polysiloxane

Fast setting and has good dimensional stability, gains more stability over time

What is best used to disinfect bite registration

EPA approved, Phenol disinfecting agent

Steps to disinfect bite

Rinsed

Disenfected

Dried

Articulate bite

Stone casts are place onto bite registration for articulator