Synchro Matrix

Shadeguides - Tips and tricks - Direct anteriors
21 Feb 2016

Building contours and contacts in anteriors is always a challenge, int his article we can learn how to achieve both in a very simple way. Is not only the matrix strategy which leads to the success of the simple anterior restorations, but the composite mass selection and its opacity which allow us to fully concentrate on the modelling technique and composite placement.

Some years ago I had terrible problems while layering 2 or more masses in anterior proximal cavities as the ones depicted below. These restoration represented a big challenge by being extremely difficult to calibrate and anticipate the color outcome by the mixture of two superposition masses as enamel and dentin. There were 3 possible outcomes:

1.- Restoration too translucent because of an enamel excess
2.- Restoration too opaque because of a lack of enamel and much display of the dentin
3.- Perfect outcome with perfect balance

Being the third situation the most unpredictable and the less common.

It has been already 8 years since I do not use 2 or more masses in these kind of restorations for many reasons, one of them is because by using a single shade with balanced opacity solves most cases with the precision shown in this final picture.

Achieving a precise contact point and a nice contour is possible by focusing all our concentration in modelling. Using a single mass helps to do so as it will be no longer necessary to think about thickness of the material. I would like to present you a simple case, that if managed wrongly could become a daily problem or vice versa.

Material necessary:
Garrison Slick Bands SM Bands
Garrison Composi-Tight M Bands
Garrison Composi-Tight Gold Bands

Fig. 1

Fig 1.- Initial situation, distal of 11 and mesial of 12 with two stained old composites. Besides the aesthetical problem, the patient referred food trapping, loose contact point and floss breaking. We decided to substitute the old restorations completely rather than only repairing them.

We will make a single shade personalised shade guide with a Body shade and we will choose the color with the best match. Depending on the composite system is not necessary to build a shade guide, the color correspondence with VITA allow to use the Vita Classical and use the correspondent body shade.

Fig. 2

Fig 2.- Before any proximal intervention we always advise to insert a tight wedge, this has 3 aims:
a) separate teeth
b) protect the rubber dam
c) displace temporarily the papilla

Fig. 3

Fig 3.- The access of the cavity, contrary to the old concept is now done through the less destructive path. In this case the vestibular composite is the perfect way to access both cavities in order to remove and clean properly. A good tip to be able to do this is by cutting the wedge almost at the level of the teeth, making it short and not capable of interfering with the bur and turbine.

Fig. 4

Fig 4.- Cavity design following a very useful rule. If the cavity extends beyond the transitional angle is strongly advised to perform a bevel. On the contrary case, if the cavity does not extend beyond the transitional angle we can leave the cavity with no further prep. Here we can see both examples, on the tooth 12 the cavity without bevel and in the 11 the cavity with a short bevel.

Fig. 5

Fig 5.- After finishing the cavities, the preparation wedge (the short wedge that we previously cut) is taken out. Further cleaning of the area outside the cavity can be done in case necessary.

Fig. 6

Fig 6.- This is the main tip of the article. Since many yearsI have been using exclusively posterior matrices in upper anterior teeth rather than any king of transparent strip. These matrices perform excellently providing an ideal proximal contour and are rigid enough to make them very easy to place. It is important to choose correctly the matrices, a very convex matrix (as is very common to find on the market) will represent a disadvantage as they tend to deform during placement. On the other hand a flat matrix will eliminate all the advantages of using a curved matrix. I personally use Garrison Slick Bands SM Bands which I found to have the ideal curvature balance.

At this stage, we place the matrices simultaneously, one per cavity, facing each other on the convex side. This strategy gives the advantage of self stabilisation of the matrix even in more extreme cases. One matrix supports the other and vice versa. There are very few cases that do not allow the synchronised placement of the matrices.

We will describe how to obtain a very strong contact point with this strategy, using all time concepts.

Fig. 7

Fig 7.- We choose one cavity and fill it up. We can do this with as many increments as necessary. Generally if the cavity is small, we do one increment on the proximal and one on the centre of the cavity.

Fig. 8

Fig 8.- Once polymerised, we will remove with strong tweezers the matrix of the completed restoration and immediately we will do a very important step which consists in pushing the wedge strongly, not how the teeth separate slightly. This procedure will create space in order to compensate the thickness of the second matrix.

Fig. 9

Fig 9.- Once completed the second cavity, thanks to the pressure of the wedge the contact will be very strong once removed. Note how the contours are rounded and will most probably look natural after finishing.

Fig. 10

Fig 10.- The wedge is removed and the contact is verified with floss. The finishing stage is done with the burs from the kit Finishing Style, specially the low speed diamond bur, discs and Spiral wheels with paste and for the last step a felt wheel.

Fig. 11

Fig 11.- Final aspect of the restoration after one year. Gloss, shape and adjustment will most probably determine the longevity and success of these restorations.