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SP 16 - Operative final > Wells and Pins > Flashcards

Flashcards in Wells and Pins Deck (13)
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1

What are Pins and wells used for?

Replacing cusps
Complex Amalgam restorations

2

When are Pins/Wells needed to replace cusps

1) When the F-L extension exceeds 2/3 the distance from a primary groove towards the cusp tip, replace the cusp
2) When the F-L extension of the occlusal prep exceeds 2/3 the distance between F-L cusps

3

What are the different types of pins?

Cemented - chemically adhered
Friction locked - placed via tapping
Threaded - uncommon

4

What is the size difference between drill and pin diameter

Drill is slightly smaller than pin diameter

5

Where are pins placed?

Approx 2 drill diameters (2mm total) from teh DEJ

6

How long are pins?

4mm long
2mm in dentin
2mm above dentin

7

T/F - pins with more than 2mm above the dentin increase amalgam retention

False

8

What is the 2-2-2-2 rule?

2mm pin hole depth
2 drill diameters in
2 mm length above prep surface
2 mm amalgam coronal to pin

9

What are the two types of drills used for pins? Which do we use?

Standard
Depth Limiting*

10

What must we be aware of in placing a pin in a tooth that has inclined or shifted?

The pilot holes for the pin must match the inclination, otherwise root or pulp perforation could occur

11

Why must we allow 1 mm of space around the pin hole?

Need a place to put restorative material

12

When can we use a well?

If you've only lost 2mm of tooth structure

13

What are the dimensions of a well?

1.5 mm deep
On a flat surface
Need to fit a 1mm condenser
Can have retention grooves for amalgam