Flashcards in Wells and Pins Deck (13)
What are Pins and wells used for?
Complex Amalgam restorations
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
What are the different types of pins?
Cemented - chemically adhered
Friction locked - placed via tapping
Threaded - uncommon
What is the size difference between drill and pin diameter
Drill is slightly smaller than pin diameter
Where are pins placed?
Approx 2 drill diameters (2mm total) from teh DEJ
How long are pins?
2mm in dentin
2mm above dentin
T/F - pins with more than 2mm above the dentin increase amalgam retention
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
What are the two types of drills used for pins? Which do we use?
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
Why must we allow 1 mm of space around the pin hole?
Need a place to put restorative material
When can we use a well?
If you've only lost 2mm of tooth structure