Pins Too Snug in Your Mainstay Articulator?

Sometimes while using the pinned Mainstay Articulating System, users find that a pin will not seat all the way down in a particular hole. The collar of the pin can be several millimeters above the hole opening causing a concern (see Fig 1). While the system is designed for the collar of the pin to go down completely, it may not always do so in certain holes.

 Fig. 1

 The first thing to do is to simply try another hole. It often will seat properly just by changing the hole (see Fig 2). Same pin, but different hole.

Fig. 2

Notice in Fig. 3, that a different pin does completely seat in the hole the other pin in Fig. 1 did not.

Fig. 3

What does this mean? It means that occasionally a pin’s metallic coating could be slightly thicker than normal. This could cause the pin to not seat completely. If this does happen, selecting another pin will usually fix the issue. The replacement pin will fully seat. The pin with the thicker coating may also fit better in another hole as there can be minute differences from hole to hole - within reasonable engineering tolerances.

In a worst case scenario where the pin is completely out the the base, (see Fig. 4) the system is still usable.

Fig. 4

While the system is designed to have the pin completely seat, in this situation, the pin will still be encapsulated in stone (see Fig. 5) and will not affect the quality of the die.

Fig. 5

Also notice the opposing ach has more than adequate room to encircle the pin in stone and not protrude through the model (see Fig. 6) causing surface issues.

Fig 6.

In the unlike case that this were to happen with pins so far out of the surface of the articulator (virtually unheard of) the key would be balancing the vertical space between the two articulator sections (see Fig 7).  Again, there is still sufficient space around both protruding pins as to not cause any function issue for case fabrication.

Fig 7. 

In conclusion, ideally the pin collar completely seats, if not, it is not a disqualifying factor for using the system. If you do experience a pin not fully seating, do not force it down. Forcing the pin will only cause frustration when removing the dies and could potentially crack the articulator.