After 4 years of the first Custom Rings case and the first article published in www.styleitaliano.org, hundreds of cases have been published in styleitaliano facebook group, and taught in several Operative dentistry programs from universities around the globe. In short, Custom Rings came to stay.
The phrase “There is no ring that adapts better, in the whole world” can sound arrogant for someone to say. But this is not the case, a customized solution will become an incredibly precise and stable separation and fixation tool for your matrices. That is the way that Custom Rings was born, one day before starting a case, a copy of the healthy embrasures was done, fearing that they were going to be lost and then the placement of a ring was going to compromise the integrity of the matrices.
We will show a simple case to illustrate the sequence and application. The biggest challenge in this case is of course not the size or the position of the margin, in a young patient the big problem is the short crowns, the embrasures are especially difficult to achieve an area with no composite excess and a tight contact as normally the rings are not stable and strong enough.
A small carious lesion on mesial of the 16 on a young patient.
The clinical aspect of the teeth barely show the lesion. We can take advantage of the healthy embrasures, in case these will be remove during cavity preparation and caries removal.
Isolation of the case. Note how the rubber dam is perfectly inverted. This is not an exercise of vanity, but a necessary step in order to prevent the rubber dam from getting trapped in between the wedge and the tooth which may lead to troubles in the marginal area.
Always pre-wedge, make no exceptions when dealing with proximal lesions. When dealing with short crowns, we break the wedge in order to be able to customize the ring, without the consistent problem of loosening it or not having it tight enough.
The wedge before cavity preparation gives several advantages as teeth separation, rubber dam protection, soft tissue relocation, hemostasis and margin position prediction. This is very comfortable for preparation.
TIP: Customization over the broken wedge, this strategy is done in short crowns to be able to gain stability. After applying My Custom Resin (Polydentia, Switzerland) we cure. It is mandatory to work with a proper material, a resin which is very hard, has quick polymerization, has a contrasting color and offers excellent cohesion between the polymerized layers in order to avoid detachment of the material.
We will place a MyRingClassico (Polydentia, Switzerland) over the first polymerized layer. It is imperative to do so in order o avoid the ring touching the tooth surface and the breakage of the resin. It is a common mistake to place the ring with the non polymerized resin.
Lateral view of the ring over the first polymerized layer.
An extra layer of resin is place afterwards to submerge the ends. This gives the customized ring an excellent resistance, stability and functionality. Now is time to detach the ring from its place.
The detached ring should reproduce perfectly the embrasures and no fractured material.
Cavity opening is done very near the proximal ridge, allowing us to easily locate the lesion, predict the opening of the external margins and most importantly, the ability to finish the cavity without touching the neighbor tooth.
Location of the margins should preferably be over enamel, but always over healthy tissues completely free of caries. The gingival margin has a magnificent position when is located at the level of the wedge, as it is the area where the matrix adapts better and the patient can clean best.
After a shy stage of caries removal, the controversial use of caries detector is done. It is especially helpful to detect caries in non-logical places. The rest of the caries removal is done very carefully, without water and with very slight touches to avoid heating the dentin. We can appreciate the healthy dentin in dry conditions.
After complete caries removal, we are ready to disinfect the cavity, remove the wedge and place the matrix.
After removing the wedge it is advisable to keep it if possible. The wedges used during the customization and preparation stages save a lot of information, one one hand, are impressed in the customized ring; on the other hand the wedge has the trimming done during the preparation of the gingival margin, making this small piece, the best possible wedge.
A black matrix was placed. It is advisable to use black matrices when the cervical tissues are white, and a silver matrix when the cervical tissues are dark, this guidelines are good to follow in order to better evaluate the adaptation of the matrices. Plastic matrices can be used as well, the authors prefer to use them in cases where the metallic ones suffer distortion, the plastic ones can return to the original shape without being ruined.
The customized ring is ready to be placed back in the cavity embrasures with the matrix in place.
Note how the customized ring makes the adaptation of the buccal and palatal margins perfect. Sometimes the contour of the matrix might seem strange (as in this case near to the buccal side) such strange foldings are generally normal. Double check the internal part of the matrix to be sure of not having a catastrophic deformation of the matrix, which is unusual, but possible with any kind of ring.
Selective etching of the enamel, no etching of the dentin was performed. A universal adhesive was used (Scotchbond Universal, 3M)
The build-up of the proximal wall was done with Body A3 (Filtek Supreme, 3M). The exact heigh of the wall was measured with the LM Arte Posterior Misura instrument.
Posterior Misura is a smart instrument that has a “fork” side which allows measuring the proximal ridge of a healthy tooth and transfer it to the adjacent tooth with extreme precision. The opposite side of the instrument has another terminal for another necessary function described in the following steps.
Aspect of the proximal wall after removing the ring and matrix.
Cavity is filled with bulk fill material color A1 (Filtek Bulkfill, 3M) 1,5 mm away from the margin. This thickness is measured with the other end of the Posterior Misura.
Posterior Misura is a 45º tapered profile which has a protrusion of 1,5mm, this structure allows the instrument to lean over the inclination of the healthy enamel of posterior cusps and push the existing material of the cavity base away of the margin, providing a 1,5 mm space which has been proved to be optimal for modeling and color purposes.
Aspect of the base built in bulk fill material.
A thorough polymerization was done to ensure excellent conversion at the cavity bottom.
Final layer was laid with an A3 body shade (Filtek, 3M)
Immediate aspect after rubber dam removal and polishing of the restoration.
One month control.
After 4 years of experience with this technique, authors can say that it is an optimal solution, unfortunately not applicable to 100% of the cases but to a vast majority, and when this is the case, many alternative solutions are available as a delta tube or a ring with silicone terminals.
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