Written by Ian Shuman, DDS Saturday, 31 March 2007 19:00
Restoring a class II preparation with composite resin can be challenging.1 Open contacts, poor anatomical contour, and an inadequate marginal seal are just some of the problems encountered. Initially, these issues were due in part to the use of amalgam matrix systems. In an evaluation by Strydom, it was shown that composite resin provides little internal force to counteract the force from the matrix.2 Therefore, unlike amalgam, which possesses a very high resistance to deformation, composites are easily forced back into their original position by a tight circumferential matrix band, with resulting open contacts. In addition, wood wedges were used with circumferential matrix bands that in combination provided poor marginal form, excess flash, and either marginal overhangs or open margins at the restorative-enamel junction.
To improve the proximal contact, instruments were designed to force the composite into a tighter contact during curing. Other techniques advocated the use of cured composite3 or ceramic inserts4 that would provide predictable contacts and proper physiological contour. Heavy-body condensable composites were introduced in an attempt to more closely resemble the handling characteristics of amalgam and create more favorable contacts. However, research has demonstrated that it is the matrix system and not the handling characteristics of the composite that determines the outcome of a favorable contact.5,6
In answer to these frustrating clinical problems, the sectional matrix and retainer ring were developed, providing significant improvement over previous devices.7,8 The sectional matrix design allowed stronger proximal contacts than circumferential matrix systems.9,10 However, the restorative outcome was not always ideal. In some systems, simple, standardized wedges designed for amalgam restorative procedures were still used, providing poor contact between the matrix and the gingival margin. A variety of custom wedge designs and concepts were proposed for the express purpose of achieving ideal contact and excellent adaptation to the cavity preparation.11-13 However, none were manufactured for clinical use. In other systems, the ring would collapse the sectional matrix into a wide box cavity preparation. It was obvious that an easy-to-use matrix system that provided a clinically reproducible, consistent outcome with excellent results was needed. These needs were answered with the Trio-Dent System (TrioDent).
Developed by a dentist, the TrioDent System (Figure 1) was a departure from previous sectional matrix, retainer ring, and wedge designs. In order to accommodate the various depths and widths of class II cavity preparations, a series of matrices were developed (Tab-Matrix). Available in 3 sizes (4.5 mm, 5.5 mm, and 6.5 mm), the Tab-Matrix is gripped at any of the holes in its 3 tabs (or handles) using specially designed Pin-Tweezers. This allows easy manipulation and simplified placement of such a small item. In addition, the tabs with their pinholes allow for easy removal using the Pin-Tweezers after a tight contact has been achieved. Anatomically, these matrices have an S-shaped curvature that replicates the true proximal surface form. Once the appropriate Tab-Matrix has been selected and placed, it is stabilized using a specialized wedge (Wave Wedge).
The Wave Wedge is a completely new concept in wedge design. In the past, wedges provided 2 functions: tooth separation, and adaptation of the matrix to the preparation margin. Because the V-Ring provides that separation, the Wave Wedge functions to seal the matrix against the margin. These wedges are provided in 3 color-coded sizes: small (white), medium (pink), and large (purple). The tapered tip and curved profile make these wedges “self-guiding” through the interproximal space. This prevents lacerating the opposing gingival papillae. They also have an adaptive seal when their fine lateral wings compress as they slip through the interproximal space and flare again upon exit. This provides ease of placement, and broad, adaptive, symmetric sealing of the matrix at the gingival margin. The Wave Wedge has a central concavity and “clicks” when placed. This “self-locating” feature ensures an optimal seal for the matrix and ease for accommodating the V-Ring. Like the Tab-Matrix, the Wave Wedge has a removal loop or hole for ease of placement and removal with the Pin-Tweezers. The hole can also be used to attach floss, thereby adding an additional element of safety. Once the matrix and wedge are placed, the specialized V-Ring retainer ring is seated to place.
The V-Ring is a unique design where the primary inner stainless steel ring with the V-shaped tines provides stiffness, while the outer Ni-Ti ring allows for elasticity and metal memory. This unique combination allows the V-Ring to separate the teeth once in place, creating a tight contact when removed. After the Tab-Matrix and the Wave Wedge are in place, the V-shaped tines of the V-Ring can easily fit over the wedge. This is possible because a space is provided for the wedge between the legs of the tines in the V-shaped grooves. The design of the V-Ring holds the Tab-Matrix in a natural anatomic form, preventing the Tab-Matrix from springing back and leaving a gap and a poorly filled restoration. In wide cavity preparations, the V-shaped tines prevent the ring from crushing the matrix and/or collapsing into the preparation, while gripping the undercuts of both embrasures tightly.
The following case report demonstrates the usefulness of the TrioDent System.
Figure 1. The TrioDent Matrix System.
Figure 2. Decayed upper right second premolar.
Figure 3. Class II cavity preparation.
Figure 4. Tab-Matrices stabilized with large Wave Wedges.
Figure 5. V-Rings seated to place.
Figure 6. V-shaped notch accommodates room for the wedges.
Figure 7. Note lack of intimate contact at the mesio-facial margin/matrix interface.
Figure 8. To create an ideal interface, additional medium size (pink) Wave Wedges were inserted through the V-shaped notches in the tines.
The patient presented for an emergency examination with the chief complaint of “a hole” in his tooth (Figure 2). Following intraoral and x-ray examination, it was determined that the upper right first molar and premolars were decayed and had failing restorations. However, the patient’s immediate problem would be addressed with the restoration of the second premolar. Pulp exposure was a concern, and the patient was informed of the potential need for root canal therapy. In patients who suffer from recurrent caries, it is best to help prevent future disease using a caries control dentifrice14 (Control Rx [OMNI Preventive Care, A 3M ESPE Company]), and enamel remineralization agents15-17 (Prospec MI Paste [GC America]) with frequent professional examinations and prophylaxes. Following cavity preparation (Figure 3), the mesial interproximal tissue appeared edematous and bled easily. This was due to chronic food impaction with subsequent bacterial infiltration, causing a chronic inflammatory response.
Due to the depth of the proximal preparations, the 6.5-mm Tab-Matrices were selected, placed, and stabilized using the large size, purple Wave Wedges (Figure 4). The V-Rings were then placed over the Wave Wedges while hugging the Tab-Matrices to the tooth and creating a separation between the adjacent teeth (Figures 5 and 6). At this point it was determined that the matrix was not achieving an absolute, intimate contact with the mesial proximal margin (Figure 7). Additional medium size (pink) Wave Wedges were inserted from the lingual (Figure 8) to provide a highly intimate contact and thus a seamless margin. This was easily achieved by simply sliding the wedges through the ample space provided by the V-shaped notch in the tine. Upon insertion, the matrix did not immediately adapt as expected (Figure 9); however, the Wave Wedge has the ability to expand once placed by virtue of its wing design. After approximately 30 seconds, the wedges fully expanded and provided excellent marginal adaptation to the cavity preparation (Figure 10). The matrices were then burnished to the adjacent teeth.
Figure 9. The Wave Wedges immediately following insertion.
Figure 10. The wedges have fully expanded and provide excellent marginal adaptation.
Figure 11. A dentin replacement flowable composite resin base is cured.
Figure 12. Enamel replacement paste composite is placed.
|Figure 13. Additional enamel shade paste composite is applied in 2-mm increments and cured.||
Figure 14. Occlusal anatomy is sculpted in the final composite layer.
Figure 15. The complete restoration following curing.
Figure 16. The Tab-Matrices are easily removed by gripping the pinhole with the Pin-Tweezers.
Following acid-etching, rinsing, and gently drying, fifth-generation bonding agent (OptiBond Solo Plus [Kerr]) was applied, gently thinned, and light-cured. Shade A3.5 flowable composite dentin re-placement (Estelite Sigma [Tokuyama Dental]) was applied in the proximal boxes (Figure 11) and light-cured. Shade A1 paste composite enamel replacement (Estelite Sigma) was applied (Figure 12) against the lingual wall using the directed shrinkage technique. Additional Shade A1 paste composite enamel replacement was applied in 2-mm increments, sculpted, and light-cured until the cavity preparation was restored (Figures 13 to 15). Following removal of the V-Rings and Wave Wedges, the Tab-Matrices were removed by gripping the pinhole with the Pin-Tweezers (Figure 16). After removal of the matrices, there was minimal flash (Figure 17), expediting cleanup and finishing of the case (Figure 18).
Figure 17. There is minimal flash of composite resin following removal of the matrices.
Figure 18. The completed case.
|Figure 19. With proper anatomical form, the gingival tissue has healed after several weeks.|
After several weeks, the patient returned for continuing care, and the upper second premolar and surrounding tissue were evaluated. With proper anatomic shape formed by the TrioDent System, the gingival tissue was able to heal (Figure 19).
Composite resin is a technique-sensitive material that requires its own unique ma-trix system. The ideal matrix system creates a tight interproximal, anatomically correct contact with minimal flash and a seamless marginal seal. The TrioDent System is proven to solve these needs in a logical, simplified, easy-to-use manner.
1. Wilson EG, Mandradjieff M, Brindock T. Controversies in posterior composite resin restorations. Dent Clin North Am. 1990;34:27-44.
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9. Loomans BA, Opdam NJ, Roeters FJ, et al. A randomized clinical trial on proximal contacts of posterior composites. J Dent. 2006;34:292-297.
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11. Gonzalez-Lopez S, Bolanos-Carmona MV, Navajas-Rodriguez de Mondelo JM. Individualized wedge. Oper Dent. 2006;31:390-393.
12. Cueto Suarez MA, Pena Lopez JM, Fernandez Teran A, et al. Passive wedge. Quintessence Int. 1996;27:243-248.
13. Re GJ, Porter KH. Contouring wedge with compound aids gingival adaptation of matrix band. J Prosthet Dent. 1986;56:514.
14. Tavss EA, Mellberg JR, Joziak M, et al. Relationship between dentifrice fluoride concentration and clinical caries reduction. Am J Dent. 2003;16:369-374.
15. Reynolds EC. Remineralization of enamel subsurface lesions by casein phosphopeptide-stabilized calcium phosphate solutions. J Dent Res. 1997;76:1587-1595.
16. Rose RK. Effects of an anticariogenic casein phosphopeptide on calcium diffusion in streptococcal model dental plaques. Arch Oral Biol. 2000;45:569-575.
17. Reynolds EC. Anticariogenic complexes of amorphous calcium phosphate stabilized by casein phosphopeptides: a review. Spec Care Dentist. 1998;18:8-16.
Dr. Shuman maintains a full-time general, reconstructive, and aesthetic dental practice in Pasadena, Md. Since 1995 Dr. Shuman has lectured and published on advanced, minimally invasive techniques; he has taught these procedures to thousands of dentists and developed many of these methods. He has published more than 65 articles on topics including creating cosmetic smiles, adhesive resin dentistry, and minimally invasive restorative and cosmetic dentistry. He is a Master in the AGD, a Fellow of the Pierre Fauchard Academy, a member of the ADA, and was named one of the Top Clinicians in Continuing Education in 2005, 2006, and 2007 by Dentistry Today. To have Dr. Shuman speak at your next seminar or to order educational materials, call (877) 4-SHUMAN or visit ianshuman.com.
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