Back to Basics: Mind the Wedge
Why mind the wedge?
What do I expect a wedge to do for me?
Well, mainly, posterior direct second class restorations. Those need special recipes. We have to mix good materials, protocols our skills and experience, and sometimes our fantasy; even if we follow the protocols, every second class is different from all the others we have done in the past, and the ones we will do in the future.
I would like to focus our attention on one of the most important points of the chain, the wedge, and try to answer the former question: what do I expect a wedge to do for me?
1) To create space by properly separating teeth to compensate for the space between the teeth that the dam and the matrix are going to make me lose.
The ring is really helpful, but only to make the matrix fit better, the size of the matrix remains to be compensated.
2) To allow the cervical fit of the matrix: this one is a real challenge because we don’t want the wedge to change the matrix shape.
What I need, is to give the right pressure only in the cervical area (light green). The parts of the wedge that remain out of this area are not important for the purpose.
CHOOSING AND USING THE RIGHT WEDGE
Choosing the proper wedge size
Now, what about the choice of the wedge? We should know the size of the wedges and the proportions between the measurements of the different wedge colors. (In the picture, ex Polydentia wedges)
Most of the wedges have a rectangular shaped section. Among them, blue and pink in section have the same height but different widths, yellow and green have the same width but different heights. Only the white wedge has the same height and width, meaning a square section.
Different wedges fill the interdental space in different ways
How to insert the wedge
We want to separate the teeth effectively, but we must analyze the space where we will have to work first, in order to choose the best wedge insertion.
By observing the interdental spaces on the occlusal side, we see that buccal and lingual/palatal interdental angles may have different shapes and combinations
Try in of the wedge
Try in of the wedges from the buccal side
Try in of the wedges from the lingual side. It is important to try both ways because we usually only use the buccal one, even if in many clinical situations it is better to use the other insertion.
TIP: Try in of the wedge should be carried out before placing the matrix. In this case the wedge from the lingual side has the better angle to fill the space. This will be our choice.
Sometimes, even on the same tooth, wedges should be placed differently on the mesial and on the distal side.
But what should a wedge do?
It shouldn’t interfere with the curvature of the matrix
Both standing in the way of the wedge, ot it leaning on the margin represents a problem for the future contact point, both for the margin adaptation of the composite and oral hygiene managment in that area.
To open this space it is possible to cut the wedge in a couple ways
Using a bur outside the mouth
Using a blade (#11 is the best) outside the mouth
TIP: An option is to put the wedge in the interproximal space and then finish the cavity. In this case, it is important to have a tool to pull the wedge and re-insert it in the same position.
This way we will mold our custom wedge for that cavity.
This is the result: now the matrix can close the space between teeth as the wedge does not interfere.
TIP: Another option not to interfere with the matrix is to put the wedge horizontally. It also gives more pressure than vertically.
If the contact point is low and the best matrix concavity is required to give the wall a proper convexity, it is possible to put the wedge horizontally with the peak oriented in the direction of the cavity; it will be important to use strips to finish the restoration in the cervical area.
If the contact point is high you can put the wedge horizontally with the base oriented in the cavity direction: it makes the matrix fit better and there is a lot of pressure in the cervical area .
Finishing the margin while the wedge is horizontally placed: the bur could not touch it.
It shouldn’t drag the dam
We need to control the operating field. We want to protect adhesion procedures from saliva, blood and breath.
To avoid dragging of the dam we can use some liquid soap.
Or just cut the tip of the wedge, in the area we have seen it is not important to stabilize the matrix, so the pressure will only be where you need it, and the tip will not drag the dam
Same case with the wedge made “shorter”
Matrix in place, the wedge perfectly works.
The wedge is a fundamental step to achieve a good second class restoration
Unfortunately it is often put in an automatic way without taking advantage of the real help it can provide.
Dedicate a few seconds to find the best wedge and the best way to use it to really make the difference between a success and a Success.
It is part of the steps that are needed to get an interproximal wall; it is made from many single easy points to follow; it is the only case in which many points do not make a line but a point… a contact point .