Posterior restorations can be a great challenge. Sometimes it can be difficult to manage different aspects of the restoration: How to clean deep decay, how to manage the contact points, provide a good shape and obtain a proper occlusion. Sometimes we have to do restorations in contiguous cavities. As the present case done in a single appointment for mesial of tooth 26th and distal of 25th.

Fig.1
Intial situation shows incongruous restorations, bad contact point and overhanging. Patient referred sensitivity. The clinical decision to replace the restorations was easily made.

Fig.2
Already under rubber dam isolation we prepare a silicon index (Express 2 putty quick 3M). It is very useful in these cases where it is not clear whether all cusps will remain or will have to be covered.

Fig.3
When cavities are opened, it is clear that the buccal cusp will be too weak and has to be covered. The silicon index will be extremely helpful in this situation. The dimension on the premolar cavity allows it to be treated directly, quickly and without complications.

Fig.4
After placing only one matrix, the wedge will have the function of adapting the matrix in the cervical portion and the ring will help the matrix embracing the tooth in the buccal and palatal margins. Now proceed with the selective etching of the enamel for 30 seconds

Fig.5
Wash with water for 30 seconds and dry.

Fig.6
Place the Universal bonding (Scotchbond universal 3M), leaving it in the cavity for at least 20 seconds, then distribute it gently with air. The surface must always have a shiny appearance.

Fig.7
Cure the adhesive at least for 40 seconds.

Fig.8
We build the distal wall of the premolar in one increment. Then the occlusal surface of the premolar with a single application, its depth should be less than 2.

Fig.9
A very important detail is that, after completing the restoration on the premolar, is possible to freely finish it and polish it, managing better the remaining space for the molar.

Fig.10
With this tool (Cusp Misura, LM) is easy to measure the thickness of the buccal cusp and decide whether to keep it or remove it.

Fig.11
The weakened cusp should be lowered 2mm. Etch only the area that we are going to build-up with the silicone index.

Fig.12
Aspect after etching, washing and drying.

Fig.13
Silicone in the canine area, a test for precision, stability and fit.

Fig.14
On the palatal side of the silicone, we can create space for the lamp.

Fig.15
After polymerizing the cusp, it is likely to have composite excess. This is easily corrected with high speed and water.

Fig.16
We treat now the cavity as a simple class II. Selective etching of the cavity is done. Note that it is not necessary to etch the composite.

Fig.17
Aspect after etching.

Fig.18
Detail of the matrix in place, thanks to the use of silicone terminals on the ring, the adaptation of the matrix is very good.

Fig.19
Bonding application.

Fig.20
Polymerization for at least 40 seconds.

Fig.21
Shiny aspect after polymerization.

Fig.22
Build-up of the mesial wall.

Fig.23
Depth measurement. This step is done to ensure that the 4mm of bulk fill material will not be surpassed.

Fig.24
Bulk fill placement.

Fig.25
After the bulk fill base, we place the last layer of body in one increment.

Fig.26
Essential lines are drawn in the occlusal surface.

Fig.27
If present in neighbor teeth, we can add stains to mimic the occlusal sulci.

Fig.28
Stains are a motivation to polymerize once more.

Fig.29
Aspect after finishing with burs.

Fig.30
Pre-polishing and polishing with abrasive rubber spirals (Sof-lex Spirals, 3M)

Fig.31
Restoration of occlusal surface completed under dam.

Fig.32
Polish the cervical area with an abrasive strip (sof-lex strip) and 2 different grits.

Fig.33
Restoration after rubber dam.

Fig.34
One year control.

Fig.35
Rx before and after.
Conclusions
Good mechanical properties of composites are now-a-days a primary factor for material selection, regardless Using an impression as an “insurance” allows us to be more efficient and less worried, providing better therapies to our patients. Combining materials such as Express 2 Putty Quick, which allows you to build a ‘’silicon insurance ‘’, speeds up our times by having a very fast hardening time. And allows us to keep the promise made by the patient, to complete the restoration in one session with direct approach.
Bibliography
Denehy G, Cobb D. Impression matrix technique for cusp replacement using direct composite resin. J Esthet Restor Dent. 2004;16(4):227-33