Getting a good contact with large GICs

Today I was in a situation where there was a 46 tooth with an MODB fracture. The mesial and distal margins were equigingval. The tooth is set for an endo or and exo but I did not have the required equipment to perform either (In the dental truck). So the plan is a temporary restoration and the patient will seek treatment privately. There are two options from here.
-Restore to decent contour and contact
-Restore with a stump with open contacts

Ideally I would have a good contact to stop food packing but at a copmromise I would consider a wide open contact to allow interdental brushes to fit in. Without anaesthesia which was my plan, Wedges would be painful and making a contact would be difficult. This was due to the equigingival margin.

In the past to make a decent contact I have used a light cure GIC like Fuji2LC and restored in stages. Sectional matricies are usually too unstable to be used due to the minimal surface area they are in contact with the tooth and there is the same issues with the wedges. Tofflemires are good fro this purpose. You do have to be careful as if tehre is insufficient remaining tooth the Tofflemire tends to collapse if tightened too much. An automatrix may be useful here. I would condition the tooth. The tightness of the tofflemire usually provides a fair seal at the gingival area. I would squeeze GIC at the base of the boxes as well as all around the gingival margin on the buccal and lingual, adapt with a ball burnisher and light cure. Then I would loosen the tofflemire, It should remain on the tooth as the GIC you have just palced should be locking it in. Then one box at a time I would squeeze GIC in to the full height of the tooth, take a ball burnisher and press it hard agaisnt the band against the adjacent tooth. The DA would then light cure the material. Then repeat for the remaining box. This succeeded about 50% of the time and usually I would end up with an open contact anyway.

Other possible strategies may include.
-Buildup in GIC then cut back and remake contacts with sectional matrices or with wedges. This way the wedges will have supragingival contact.
-Use LA and wedge subgingivally with or without gingivectomy.

Today however I used a chemical set GIC Fuji7. I noted that during the setting process I was be able to pack the GIC agaisnt the adjacent tooth. One advantage of this method is that there aren't multiple layers so less chance of air bubbles. There is also less time pressure. One disadvantage of the old method was that once the tofflemire was loosened, I couldn't guarrantee that the new layer would flow into the gap opened up between the matrix and the first layer. This could lead to more discrepancies.
The method so far is:
-Tofflemire and conditioner
-Fill the tofflemire band and cavity with chemical set GIC.
-Keep the patient's mouth open and keep lightly touching the material surface with a ball burnisher to check the setting process.
-As soon as there is some solidity to the material, loosen the tofflemire and fwith firm pressure, pack the material laterally against the adjacent teeth.
-Completely remove the tofflemire retainer leaving the band in place and repeat the condensation. After 1 minute, jiggle the band ends to loosen them against the tooth embrasures. There should be a fair contact between the material and the band in 4 surface restorations so pulling the band here would likely dislodge the GIC.
-There is likely an overcontoured lingual or buccal surface due to the shape of the toffleire so get a sharp instrument i.e a sickle probe and tease the band off the GIC surface. Then it should be relatively easy to remove the band from the interproximals.
-Wait for full set then contour and polish.

In the case today It worked fairly well and the contacts looked better than I have ever been able to get them in the past. A BW after showed a fair overhang which should be easily removed. My worry long term is that the manipulation in gel stage could cause cracking or misadaptation in the material against the tooth. This would happen if the condensation came too late or took too long. This is why I suggest you do it as soon as possible.

I will keep an eye on these cases to see if they lead to early failures.

 





FOLLOW UP
The mesial ridge of the restoration fractured about 2 weeks after placement. This is likely due to a high spot on the restoration. on review, the distal contact isn't as tight as I initially though. In fact, there is still a very subtle open contact that is trapping food. I likely need to have wedges to separate the teeth to have any hope of getting a tight contact. The contact will always be open the thickness of the matrix band unless there is some sort of separation.

I easily repaired the fracture with a composite addition. It allowed me to get a perfect contact with the V3 system. This is likely the protocol I will follow with composite additions to make a tight contact.