The patient presented with an open contact between the first and second molars with resulting interproximal caries as a result of chronic food impaction. Following caries removal, it was noted that the distal box was relatively wide, but the mesial box preparation was narrow due to the minimal caries in this area (Figure 4). Sectional matrices were placed at both the mesial and distal of the tooth to be restored. A small wedge (pink) was placed at the mesial, and a large (purple) distally. Triodent V3 rings were placed at both the interproximals (Figure 5).
The preparation was rinsed and lightly dried to eliminate any pooled water. A solvent-free self-etch adhesive (Bond1-SF [Pentron Clinical Technologies]) was vigorously rubbed into the prepared dentin and enamel surfaces for 20 seconds (Figures 6 and 7). The resulting surface should have a glistening appearance (Figure 8): once this was visually verified, it was light-cured for 10 seconds (Figure 9).
A layer of dentin shade B3 nanocomposite (Artiste Nano Composite [Pentron Clinical Technologies]) was adapted to the pulpal floor, proximal boxes, and over all prepared dentin surfaces. Lobes were formed and pits/fissures developed with a cone burnisher (PKT-3R, Zoll Dental), then light-cured (Figures 10 and 11).
To replicate a more natural aesthetic appearance, a brown tint (Artiste Maverick posterior pit tint [Pentron Clinical Technologies]) was applied with a No. 8 endodontic hand file to the pits and fissures created in the dentin layer of composite. This was then light-cured (Figure 12).
A layer of shade B enamel nanocomposite (Artiste Nano Composite [Pentron Clinical Technologies]) was placed over the dentin composite, using an acorn burnisher (21B [Zoll Dental]) to adapt it and to create the desired anatomy (Figure 13). The restoration was light-cured from the buccal, then the lingual, and finally the occlusal surfaces (Figure 14). The restoration was now ready for finishing and polishing (Figure 15).

Next, the rings, wedges, and matrix were removed (Figure 16). As the proximal contacts are often very tight as a result of using this ring system, it may be necessary to use a locking hemostat to remove the matrix. Needle-shaped finishing carbides (ETS 8.5 [Brasseler USA]) and diamonds were used to remove any flash on the buccal and lingual. This was followed by football-shaped carbides (H379F [Brasseler USA]) and diamonds (D051 379F [Brasseler USA]) to contour the cavosurface margin (Figure 17). Final polishing was performed with polishing disks (Fini [Pentron Clinical Technologies]) followed by polishing paste (Fini Polishing paste [Pentron Clinical Technologies]) on a felt point (Felt buff polisher [Pentron Clinical Technologies]) (Figure 18).

CONCLUSION
Posterior direct resin restorations can be accomplished with excellent proximal contours and tight contacts by using well-designed rings, matrices, and wedges. This, in combination with a simple layering technique using modern nanocomposite resin materials, allows the dentist to mimic the aesthetics and anatomy found in nature.

T-bands The T-bands that provide the best contacts are the .001 inch brass matrices. These bands can provide quick and easy matrices, and I use them for children and teenagers. I prefer the straight (vs. curved) narrow T-bands for primary teeth. These bands are used with wedges and provide tight contacts for Class II restorations in young children.

Omni-matrix The Omni-matrix? (Ultradent Corp.) has several advantages over the classic Tofflemire? retainer. The Omni-matrix has both pediatric and adult sizes and has the advantage of using metal or mylar strips.

Sectional matrices with separation rings According to Loomans, B.A., et al: “The use of sectional matrices combined with separation rings resulted in tighter proximal contacts compared to when circumferential systems were used.”2 I have found this to be true in both primary and permanent teeth when restoring Class II resin composite, compomer, resin-modified glass ionomers, and glass ionomer materials.

(2) The assistant, with the dental officer, will prepare materials designed to
replace the missing walls of a cavity preparation and to shape or protect the restoration.
Placing a matrix for an amalgam restoration will allow the dental officer to insert the
restorative material without exceeding the limits of the normal tooth structure. The most
common type is the Tofflemire matrix retainer and band. This comes in two parts–a small
stainless steel band that encircles the tooth and the instrument that holds the band in
place (called the Tofflemire retainer). Note that the number 1 Universal band is doubled
over when it is placed in the retainer. In assembling and placing the matrix, there are
three essential rules to follow. First, the small opening of the band must point toward the
cervical portion or root of the tooth. Secondly, the slotted side of the retainer always
points toward the root of the tooth to facilitate the removal of the retainer after the
restorative material has partially set or crystallized. Finally, the retainer is usually
positioned on the facial side of the tooth being worked on (in the vestibule).