QUIZ 2: Gingival Displacement and Tissue Retraction

Define tooth preparation

Process of removing diseased tooth structures and shaping the tooth biomechanically to receive and retain a restoration

Why is marginal fit of restoration essential? What is a perfect marginal fit restoration called?

must have a marginal fit to prevent recurrent caries and gingival irritation

finish line exposure

Define gingival displacement

also known as gingival retraction

the deflection of the marginal gingiva away from a tooth

process of exposing the preparation finish to line by pushing the gingiva away from the prep

What is the shoulder type of finish line?

metal ceramic crown

all ceramic/porcelain

jacket crown

What is the bevelled shoulder type of finish line?

buccal of metal

ceramic crown

What is the heavy chamfer type of finish line?

high strength porcelain crowns

buccal of metal ceramic crowns

What is the chamfer type of finish line?

full metal crowns

palate/lingual of MCCs

resin bonded crowns

What are the purposes of gingival displacement? (5)

1. Control bleeding w/ retraction cord or compression cap

2. Enhances placement of preparation margin

3. Provide access of margins for final impression

4. Ease for die trimming

5. Well fitting crowns

What are the clinical uses of gingival displacement? (9)

1. Crown Preparations

2. Amalgam / Composite Restorations

3. Class V's

4. Root Caries

5. Veneers

6. Final Impressions

7. Bleeding control

8. Die Trimming

9. Cementation of crowns

What is the workflow of gingival displacement?

1. tooth prep

2. final impression

3. master cast

What are the mechanical methods of gingival displacement? (4)

Physically displacing the gingiva through:

1. Copper band or tube

2. Rubber dam

3. Cotton cord

4. Retraction cord

What are the chemicomechanical methods of gingival displacement?

combination of chemical action with pressure packing

cord with epinephrine

What are the surgical methods of gingival displacement?

Rotary Curettage

Electrosurgery

What are the properties of a retraction cord?

knitted / braided

filled or not w chemicals

What chemicals can a retraction cord be filled with?

Astringents

Hemostasis

Ferric sulfate

Aluminum chloride

Racemic epinephrine (cardiovascular effects)

What is the single cord technique?

Single cord is placed in the sulcus then removed prior to impression

What is the double cord technique?

Two cords placed one above the other and then removed prior to impression

one may stay in sulcus prior to impression

What determines the type of cord packing technique?

the depth of the sulcus

What type of cord packing technique do you use when the depth of the sulcus is SHALLOW?

single cord, medium diameter cord

What type of cord packing technique do you use when the depth of the sulcus is DEEP?

double cord, first cord should have a small diameter and second cord has a wider diameter