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Dr. Ray Betolotti -  Perfect posterior composite contacts & anatomy shaping made easy.

Important Clinical Information on Bonding of Posterior Composites

We wish to provide all interested clinicians with information on one of the most popular topics in the seminar: how to achieve perfect posterior composite contacts. We are constantly amazed that this topic is such a well kept secret.  Dr. Bertolotti has been teaching it for more than ten years now. It is one of the keys to phasing out the amalgam and implementing posterior composites as the treatment of choice.

How To Get Perfect Contacts:

Learn how to use them below

The Contoured Matrix sectional matrix and Spring Ring Retainer ring has historically been the surest method of establishing a tight and anatomically correct contact in either composite or amalgam. It is now challenged by two other systems which work similarly, Danville Contact Matrix and Garrison (GDS) Composite. The method continues to be one of the best kept secrets in restorative dentistry.

The matrix is placed in the obvious interproximal position. Two may be used simultaneously for MOD restorations. Alternatively one interproximal surface may be done at a time. It is often necessary to adapt the matrix at the gingival margin with a wedge or perhaps with a paper point or even gutta percha (the paper works well with a rubber dam). If the matrix adapts without a wedge, the wedge is not necessary when a flowable composite is used for the first increment. (Unlike "packable" composite, the flowable composite exerts very little force on the matrix.) The following figure illustrates a typical placement:

Fig. 1 Fig. 2

The ring is placed by spreading it with an "Ivory type" rubber dam forcep, gripping with the sides of the forcep, not the points. The ring adapts the matrix to the tooth and provides separation (since it is a spring pushing from both sides). Note that the ring should preferably be placed along side the wedge, not vertically above it (to get better ring retention and to push the ring away from the prep, preventing collapse of the matrix into a wide prep).

Most Spring Ring Retainer rings have flat tines. The "flats" of the ring are intended to touch the matrix. If the "end" touches the matrix, it tends to collapse into wide preps. Danville rings are made in two models to optimize the adaption of the matrix and prevent collapse of the ring into the prep. One model arcs away from the tooth being restored (as illustrated above) and the other arcs over the tooth being restored. The Spring Ring Retainer ring is intended to arc away from the tooth being restored, as in figure 1. A pair of normal Danville rings is illustrated in figure 2 while a normal and "reverse" Danville ring are illustrated in figure 3.

Fig. 3 Fig. 4

The GDS ring does not have flats so it is omnidirectional but unfortunately it tends to collapse into wide preps as shown in figure 4. The Danville and Other Spring Ring Retainer rings have flats which are designed to prevent this collapse by pushing the matrix against the tooth with the aid of the flats (see figure 5).

Fig. 5 Fig. 6

The Danville ring also has the advantages of 15 degree offset angle on the occlusal (to allow multiple ring stacking) as illustrated in figure 6.

Another feature of the Danville rings is a converging taper of the tines, resulting in a self-retentive nature lacking in many designs. The GDS likewise has a good self-retentive design but unfortunately, in my opinion and according to numerous clinicians, lacks sufficient separating force for good contacts.  The  Danville has better separating force.

For those interested in how separation results without wedges, the following diagram, figure 7, will explain the physics. Equal and opposite spring force is exerted from each side to separate the teeth. The longer the ring is in place, the more separation. In the clinic, about 5 minutes seems ideal for most restorations.

Fig. 7

 

Posterior Anatomy Shaping, the easy way with
"TOP-SPIN" diamonds.

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