Line Angle?

[queenbee21]

Hello Fellow dentists,

I am quite confused about line angles and pins for amalgam. I thought you can only place one pin at each line angle and the maximum amount of pins you can place on any which tooth is 4.

How many line angles does each tooth have and how do we determine this?
Where do we put the pins for amalgam?

Thank you!

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[Decan]

Line angles are where two surfaces meet (if I counted right, 6 for anteriors, 8 for posteriors). Point angles are where three surfaces meet (4 for both anteriors and posteriors). We're taught to place pins where you're replacing a cusp...so place the pin wherever the cusp would be if the tooth was intact.

I hope that helps!

 

[HupHolland]

For practical purposes, you would never realistically place more than 4 pins in a molar (MB, ML, DB, DL line angles) and 2 pins in any other tooth.

Actually, for practical purposes, you would never place a pin in practice.

Hup

 

[Vapor1122]

Actually, for practical purposes, you would never place a pin in practice.

I was going to ask, how many schools still teach pins? They were mentioned in our restorative classes here at NYU, but we've always been told they're a product of yesteryear's dentistry and aren't used anymore.

 

[Decan]

Hup, quick question for you. I placed a couple of pins on #15 the other day to retain an amalgam core (later restored with a FGC) because there was no buccal tooth structure, and very little lingual tooth structure. We're taught that even though resin cores bond to tooth they still need mechanical retention. What would you use in private practice?

Thanks!

 

[DrJeff]

Hup, quick question for you. I placed a couple of pins on #15 the other day to retain an amalgam core (later restored with a FGC) because there was no buccal tooth structure, and very little lingual tooth structure. We're taught that even though resin cores bond to tooth they still need mechanical retention. What would you use in private practice?

Thanks!

Cut a couple of slots into the dentin and/or other remaining tooth structure before bonding the core material is one answer. Or the other answer in many cases, is if there isn't enough supragingival tooth structure left after the "traumatic event" (cusp fracture, existing restoration loss, caries removal, etc), then root canal therapy as a means to gain more surface area with better mechanical features for retention of the core prior to placing a full coverage restoration.

You'll see and here many examples of how pin(s) placement can work longterm for a restoration, but you also won't see too many pin retained restorations these days because there's ver often many detrimental side effects that they can cause too! (loss of restoration, pulpal damage, fractures of the surrounding tooth structure, etc)

 

[scottyhoop]

Cut a couple of slots into the dentin and/or other remaining tooth structure before bonding the core material is one answer. Or the other answer in many cases, is if there isn't enough supragingival tooth structure left after the "traumatic event" (cusp fracture, existing restoration loss, caries removal, etc), then root canal therapy as a means to gain more surface area with better mechanical features for retention of the core prior to placing a full coverage restoration.

You'll see and here many examples of how pin(s) placement can work longterm for a restoration, but you also won't see too many pin retained restorations these days because there's ver often many detrimental side effects that they can cause too! (loss of restoration, pulpal damage, fractures of the surrounding tooth structure, etc)

Dr. Jeff...I was asked by a professor in clinic the other day to place pins in #14 for an amalgam core build up. All that remained of the tooth was the buccal wall. I told the professor I would rather do an amalgam pin instead of the traditional pin placement and they were ok with that. What are your thoughts on amalgam pins? We were taught that they are stronger than pins. Do you agree?? Thanks!

Scotty

 

[dragonteeth]

Wow you must have gotten one of the older guys or an adjunct then. They were moving away from pins when I was there at VCU, and I graduated in 2000.

 

[scottyhoop]

Wow you must have gotten one of the older guys or an adjunct then. They were moving away from pins when I was there at VCU, and I graduated in 2000.[/QUOTE

Hey dragonteeth...it was a actually a newer full time faculty member that this happened with so maybe that's why? We had to learn to place pins in preclinic lab as well. I kinda thought pins were outdated too, but I guess some people still think it's a good treatment option. Still being relatively new to the game, I have to do some homework on it, but I feel much better about placing amalgam pins then having to drill a pilot hole then screw in one of those little buggers! haha...I've fractured more than one ivorine tooth that way!

Scotty