Written by Jeffrey M. Rosenberg, DDS Monday, 18 March 2013 08:58
The importance of a proximal contact is both supportive and protective in nature.1 A 1939 drawing by G. V. Black illustrates findings which we see on a daily occurrence; contacts of teeth are both protective and deflective in regards to plaque and food accumulation (Figure 1).
The contact supports the interproximal papillae and deflects trauma away from the col area. Inadequate contacts may result in plaque accumulation and incipient dental caries (IC), aggravating food impactions that damage the interproximal tissues, drifting of adjacent teeth, and root proximity issues.2 It is critical to be able to predictably make proper (“correct”) contacts when restoring teeth.
Restoration of interproximal areas on posterior teeth requires preoperative evaluation of tooth size and position; defect size and location; contact tightness, location and size; adjacent tooth position; size, contours, contact location,and gingival location.
With challenging economic pressures, the number of posterior direct versus indirect restorations restoring proximal contacts is likely to increase. In addition, the controversy of mercury in dental amalgams being seen as an outdated, unhealthy restorative alternative does not seem to be waning.3,4 Resin-based posterior restorations are placed twice as frequently as amalgam restorations.5 When I started my dental practice, amalgams were routinely placed, patients did not mention “white” fillings, and insurance companies did not reimburse for resin restorations. Presently, my patients assume that I am placing tooth-colored fillings. Clinicians these days must be able to restore multiple posterior teeth with direct resin in an efficient and predictable manner. Are clinicians able to predictably and consistently place well-sealed posterior resin restorations with excellent contours and contacts? My review of the literature leads me to believe that we are still looking for great techniques for the placement of Class II resin restorations.6,7 Even more daunting may be the search for techniques to place multiple and adjacent posterior resins successfully.
This article presents a protocol for placing multiple posterior resins in adjacent teeth, resulting in excellent marginal seal and ideal interproximal contacts (Figure 2).
Characteristics of a “Correct” Contact
It should be remembered that the posterior interproximal contacts develop in the dentition through the eruption and migration process. Therefore, making contact is more challenging than it is in nature, as it is necessary to reconstruct the anatomy through a process that “drops” the restoration into a predefined space.
|Figure 1. The 1939 G. V. Black analysis of a posterior contact. CP—contact point; IC—area cervically adjacent to the contact point, the most common site of incipient proximal caries; NSG—normal septal gingiva which usually protects any presenting proximal surface concavities on the cervical part from the establishment of hypersensitivity or caries. ACJ—amello-cemental junction: As the gingiva recedes toward this zone, there is a tendency for the proximal surface thus exposed to assume a concave form (PAC) which usually continues and becomes deeper as it reaches the root surface. RSG—receded septal gingiva; BGC—buccal gingival crest; LGC—lingual gingival crest.||Figure 2. Naturally occurring contacts.|
|Figure 3. SuperCurve Matrix (Triodent).|
Interproximal contacts should have the following characteristics:
- The contact tends to be centered buccolingually below the marginal ridges.
- The contact tends to be highly convex in its middle and occlusal thirds.
- The contact surface tends to be flat or concave in the cervical third.
- If there is gingival recession, there is a tendency for the cervical third to assume a concave form.
It becomes necessary to select a matrix system that reflects these characteristics in its design. Studies show that sectional matrices resulted in statistically tighter contacts for posterior resin restorations.8 One such system (V3 Matrix [Triodent]) includes sectional matrices that mimic the contours necessary to achieve a “correct” contour, along with a ring design capable of predictably creating consistent contacts. Triodent has recently improved their sectional matrices by introducing the SuperCurve Matrix line. These matrices are biomimetic in design, being shaped and coated for ease of placement and removal (Figure 3).
Planning for Placement of Multiple Adjacent Restorations
To achieve success in restoring multiple adjacent posterior resin restorations, the process must start by making some preliminary assessments.
- Examine the extent and location of caries—visual and radiographic analysis.
- Assess the adjacent teeth for existence of normal anatomy—accept or modify?
- Protect the adjacent teeth during the preparation process to preserve anatomy and maintain a smooth surface, thereby reducing plaque accumulation.
- Prepare teeth with an efficient sequence.
- Determine type and location of matrices.
- Establish sequences of steps if adjacent contacts are going to be restored so successful anatomic contours are reconstructed.
- Use the pre-etch technique9 to optimize the seal of the occlusal portion of the restoration.
- Use a proven adhesive system to create an adhesive seal of the resin to tooth structure.
- Use of glass ionomers in the proximal cervical area in high-risk caries patients or in root caries.
A 57-year-old male presented with maxillary bicuspids with adjacent Class II resin restorations. Radiographic examination revealed reoccurrence of caries, necessitating the replacement of the existing restorations. Clinical examination revealed periodontal probing depths of 2.0 mm with approximately one to 2 mm of gingival recession in this area. Adequate tooth structure was available for direct resin replacement, and the occlusal scheme was suitable for the procedure as well. The first bicuspid would need a distal occlusal (DO) restoration; the second bicuspid a mesial occlusal (MO) replacement. The existing distal restoration of the first bicuspid was did not have ideal anatomy (Figure 4).
A prepreparation occlusal bite marking 40 µm articulating ribbon (Arti-Check [Bausch]) was obtained with articulating ribbon to ascertain where the preparation might need modification to keep the occlusion off of a tooth/restoration seam. Next, isolation was obtained (Isolite System [Isolite Systems]). The occlusal enamel and adjacent fissures were initially treated with 37% phosphoric acid gel (Ultra-Etch [Ultradent Products]) as a part of the pre-etch technique.10
Preparation was expedited by placement of a wedge (WedgeGuard [Triodent]), inserted to protect adjacent tooth structure from damage of the rotating burs. It addition, it serves separate the teeth slightly (Figure 5).
|Figure 4. Pretreatment adjacent failing Class II resin restorations.||Figure 5. Wedge (WedgeGuard [Triodent]) was inserted to facilitate tooth separation and rapid preparation.|
|Figure 6. Final adjacent preparations.||Figure 7. Placement of sealed adjacent matrices with Wave-Wedge (Triodent).|
|Figure 8. Simultaneous adhesive preparation of seated matrices.||Figure 9. IPC instrument with convenient “hot dog” form of resin for placement in proximal area.|
|Figure 10. Placement of proximal wall with resin hot dog form.||Figure 11. Completion of first restoration and proximal wall of adjacent tooth.|
The author uses a sharp fissurotomy (carbide) bur (SS White Burs) for fast initial access, and to simultaneously probe fissures and areas of dental caries. Existing resins in both bicuspids were removed, and any secondary caries as well. A caries indicator dye (Caries Detector [Kuraray America]) was applied to facilitate confident removal of only the irreversibly diseased dentin. Final caries removal was accomplished with a No. 4 round bur (SS White Burs). The preparation margin was finished with a 557 diamond (Premier Dental Products), and peripheral margins were beveled with a flamed 862L-018 Neodiamond (Microcopy). The final cavity preparations’ residual debris was cleaned with a water-alumina oxide slurry using the PrepStart H2O (Danville Materials) (Figure 6).
Matrix Application for Multiple Teeth
Pin-Tweezers (Triodent), a positive holding plier, were used to carry 2 regular-sized 4.5-mm V3 Tab (sectional) Matrices to the teeth simultaneously. Other matrix systems can be used for multiple resin placement, but none is faster or predictable than the use of sectional matrices.6 The tabs on Tab Matrices were temporarily folded upon each other to facilitate multiple placement. The Pin-Tweezers secured a purple (large) Wave-Wedge (Triodent), which was placed between the matrices. Then, the tabs were returned to a vertical position (Figure 7).
There is no need to burnish the contact with this technique. Evaluation was done make sure there was a tight adaptation of the matrix along the gingival margin. If there had been any gap along the gingival margin, another Wave-Wedge of smaller or similar size would have been placed from the opposite side of the tooth, stacking the wedges and completing the seal. The matrices were stabilized with light finger pressure and a yellow (narrow) V Ring was placed. The matrix application was reassessed to make sure matrix/tooth interfaces had excellent adaption.
The peripheral enamel margins were previously etched. These margins can be freshened with a 5-second, or even 15-second etch if the pre-etch step was not performed (selective etch technique). A high strength self-etch bonding agent with antibacterial cavity cleansing properties (SE Protect [Kuraray America]) was placed according to the manufacturer’s directions (Figure 8). It is important to note that a glass iononer liner is used in high-risk caries patients and in root caries situations.
|Figure 12. Restorations upon initial completion.||Figure 13. Occlusal adjustment with the fissurotomy carbide bur (SS White Burs).|
|Figure 14. Finishing with a disc (Soft-Flex [3M ESPE]).||Figure 15. Completed restorations.|
Sequence of Resin Buildup to Achieve Excellent Contacts
A thin layer of a heavily filled flowable resin (Majesty Flow [Kuraray America]) (deep chroma shade A3.5) was placed in both proximal boxes and in areas of sharp preparation angles. The heavy-filler content has excellent radiopacity and results in low polymerization shrinkage. This is critical in the proximal box, which is an area prone to caries reoccurrence. This “heavy-flow” layer sets up a strong bond to the adhesively prepared dentin, resisting gap formation from tensile forces generated when subsequent resin layers were placed. The deep chroma mimics the dentin shade for a natural appearance. Filling both proximal boxes “sets” the matrices to prevent movement and enhances accuracy of the adjacent contacts. This flowable layer was cured for 30 seconds.
A high value, nanofilled composite filler with a high refractive matrix was used (CLEARFIL MAJESTY Esthetic [Kuraray America]). This resin is easy to sculpt and exhibits a light diffusion property very similar to natural tooth structure. The high refractive matrix provides a slight transparency after light-curing, which demonstrates similar optical characteristics of natural enamel.
The assistant creates convenient “hot dog” forms to facilitate wall and cusp forms. These forms are transferred with an IPC instrument that allows rolling of the hot dog into the desired shape (Figure 9).
The mesial wall of the second bicuspid was constructed by placing a hot dog form along the matrix wall. The occlusal embrasure is created by holding the IPC instrument at a 45° angle away from the matrix and sweeping from lingual to buccal. A rolled, convex marginal ridge will be formed (Figure 10). Gaze down the line of adjacent teeth’s marginal ridge heights to set the correct marginal ridge height and reduce final adjusting. This section was cured for 30 seconds.
Simple Tinting—Cusp inclines
A Microbrush was wetted with Kolor + Plus white tint (Kerr) and placed in the area of the cuspal inclines. (The tint is best used under the anticipated cusp and ridge resin pieces.) The rest of the tooth anatomy (buccal and lingual cusp inclines) was created by laying opposing hot dog resin pieces into the preparation. Each cusp were cured briefly (3 seconds) to reduce polymerization shrinkage. Condensation and smoothing any irregularities was performed with a resin-wetted Microbrush in order to avoid any step between the enamel surface and the filling material. A 30-second cure then followed.
With the first restoration and contact completed, the process of forming the adjacent contact was completed by repeating the wall formation of the distal of the first bicuspid. Once the wall was formed, the retaining ring could be removed for ease of completion, allowing better visualization of the contiguous contact (Figure 11).
The first bicuspid restoration was completed with the same technique using the blade of the IPC and the Microbrush coated with a resin wetting agent (Seamfree [Apex Dental]) to complete and smooth the anatomy (Figure 12).
Finishing and Polishing
Definitive occlusal adjustment was minimal and accomplished with the fissurotomy bur. This carbide is ideally shaped for anatomically precise adjustments (Figure 13). Next, medium grit discs (Soft-Flex [3M ESPE]) were flexed against the interface of the matrices and the resin to further roll and polish any flash along the proximal contours (Figure 14). Final polishing occurred after verification of the occlusion with a 40-µm articulating ribbon. The restoration was highly polished in 30 seconds with a diamond impregnated brush (Groovy Diamond Polishing Brush [CLINICIAN’S CHOICE]). A surface sealant (Surface Coat [Kuraray America]) was placed in conjunction with a final cure of 30 seconds (Figure 15).
A systematic process for restoring adjacent contacts has been presented. The technique focuses on reducing repetitive steps while using efficient supplies and instruments to predictably produce anatomically correct contacts. The author believes all or portions of this technique can be delegated to chairside auxiliaries as well. The end result should be reduced operator stress, better clinical outcomes, and increased profitability.
- Terry DA. Restoring the interproximal zone using the proximal adaptation technique—Part 2. Compend Contin Educ Dent. 2005;26:152.
- Dörfer CE, von Bethlenfalvy ER, Staehle HJ, et al. Factors influencing proximal dental contact strengths. Eur J Oral Sci. 2000;108:368-377.
- Brownawell AM, Berent S, Brent RL, et al. The potential adverse health effects of dental amalgam. Toxicol Rev. 2005;24:1-10.
- Ottenga ME, Mjör I. Amalgam and composite posterior restorations: curriculum versus practice in operative dentistry at a US dental school. Oper Dent. 2007;32:524-528.
- Christensen GJ. The future: materials, challenges in dentistry, and education. Dent Today. 2012;31:102-106.
- Chuang SF, Su KC, Wang CH, et al. Morphological analysis of proximal contacts in class II direct restorations with 3D image reconstruction. J Dent. 2011;39:448-456.
- Saber MH, Loomans BA, El Zohairy A, et al. Evaluation of proximal contact tightness of class II resin composite restorations. Oper Dent. 2010;35:37-43.
- Loomans BA, Opdam NJ, Roeters FJ, et al. Comparison of proximal contacts of class II resin composite restorations in vitro. Oper Dent. 2006;31:668-693.
- Doukoudakis S. Establishing approximal contacts in class 2 composite resin restorations. Oper Dent. 1996;21:182-184.
- Rosenberg JM. The pre-etch technique for achieving enamel bond strength with self-etching systems. Pract Proced Aesthet Dent. 2004;16:764,766.
Dr. Rosenberg maintains a private practice in Philadelphia, Pa, emphasizing restorative and aesthetic dentistry. He is a Fellow of the AGD and holds associations with various restorative, aesthetic, and orthodontic organizations. He publishes in this field to increase awareness of high-tech materials and procedures and performing dentistry more efficiently and with higher quality. Dr. Rosenberg places hundreds of bonded restorations monthly and has a patent pending in the area of nonmetal dental restorations. He is also the head of The Dental Healthcare Group, which provides high-quality continuing education in the Philadelphia area. He can be reached at (215) 592-4747.
Disclosure: Dr. Rosenberg received materials for use to prepare the clinical case for this article from Triodent and Kuraray America.
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