Choose a matrix (part 1)
This article is a 3 part article. You can see the following articles here part 1, part 2 and part 3
Placing matrices in the anterior teeth is always a challenge, not only because a correct sealing and a solid contact point must be established, but a flawless contour must be achieved. In a not so distant past, the first choice for an anterior matrix has been the classical strip roll transparent matrix.
Transparent strips were applied after building the palatal wall, preferably wedging the interproximal areas. These matrices accomplished the task of sealing the gingival margin of the restoration.
The main problem for these kind of matrices was evident. The profile of the restoration was very straight, giving us as a result a great disadvantage, that usually was corrected on the finishing and polishing stage. Sometimes, when the neighbor tooth allowed it, this was easily done with the use of rotatory discs, but when the neighbor tooth contacts towards the incisal edge, this correction becomes very difficult and usually with not great results.
As a first alternative, especial posterior matrixes were adopted for the anterior region with great results, although some minor disadvantages can be found.
Sectional transparent matrixes (Hawe adapt, Kerr) become a method for everyday dentistry on the achievement of the proximal anatomy of the anterior teeth thanks to their intrinsical elasticity which allows an optimal adaptation to a large number of teeth.
The relation of perfect interproximal contact points becomes more intuitive and immediate , with optimal emergence profiles, strong contacts and the minimal material excess in a single tooth or in multiple restorations.
The ideal aim, as a matter of fact, will be to achieve a restoration that requires very little or no finishing procedures at all in the proximal area.
Working with anatomical matrices, we can be very precise on giving a perfect contour. When working with neighbor cavities, two matrixes can be placed at the same time, one of them will have the perfect contour, and the second one will act as a support for the first matrix. After modeling the first wall, that matrix will be removed so that the second matrix can achieve a better contact point.
This excellent matrix system, developed originally for the treatment of interproximal posterior cavities, adopting these matrixes to the anterior sector may seem an ideal approach, but they still have the huge disadvantage of not having a low height to cover the whole marginal ridge, and some times the transparent configuration of the matrix sometimes makes it difficult to verify the perfect seal of the matrix on the gingival margin and the exact amount of applied composite resin.
Final picture of the case, with excellent contours in the proximal areas.
Another case showing the perfect contour adaptation, and sometimes the great disadvantage of this system, not long enough.
One matrix acts as a support during the construction of two cavities. Is important to remove one matrix after the first wall has been done.
The final case shows perfect contours and good integration of the material.