The direct Class II composite restoration is one of the most common restorative procedures in dentistry. Unfortunately, it continues to be a complicated, frustrating, and often unsuccessful procedure for many clinicians. Recently, this became even more obvious when I heard a trainer encouraging new in-office CAD/CAM users to do indirect Class II inlays as a substitute for direct Class II composite restorations. The argument was that, because direct Class II composites are so unpredictable and complicated, it would be easier and better to do indirect Class II in-office CAD/CAM restorations. During the break, most of the dentists whom I spoke with were in immediate agreement with this rationale and were planning to follow the trainer’s advice in their practices.
Every year, I lecture at a variety of continuing education events for many doctors, and, yes, the Class II direct composite restoration continues to be mentioned as a source of irritation and dissatisfaction. With frequent postoperative sensitivity, recurrent caries, the length of time these procedures take, and the challenges in creating ideal interproximal contacts, these restorations can indeed be a source of frustration.
When comparing CAD/CAM to minimally invasive supragingival direct Class II treatment options, there are several things to consider. The time it takes to prepare and then take a digital impression, mill, and cement an indirect Class II restoration is considerably longer than a direct composite alternative. Establishing proper draw for the CAD/CAM restoration requires additional healthy tooth structure to be removed (Figure 1), potentially having unhealthy negative consequences for the pulp1 and the periodontium.2,3 The more tooth the clinician cuts away today leaves less tooth structure available (if needed) in the future, and, if/when the restoration fails, we often have to move into an even more aggressive restorative option. CAD/CAM users are also encouraged to create gingival clearance to permit good scanning and drop deeper subgingival margins. Lastly, it is inaccurate to assume that an indirect restoration will outperform a direct one: As with normal size Class II restorations, direct restorations will likely be as or more durable than indirect ones.4
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| Figure 1. A traditional indirect inlay preparation with tapered walls, requiring approximately 3 times more tooth structure to be removed. | Figure 2. Injecting one-third carpule below the muco-gingival line. |
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| Figure 3. Injecting one-third carpule below the distal papilla and then one-third below the mesial papilla. |
Unlike the disadvantages of the indirect restorative option mentioned above, there are many benefits to the supragingival and minimally invasive direct composite restorative choice, including a lower cost to the patient (Table 1). Thus, being able to do a fast, predictable, and beautiful Class II direct composite has the potential to make the life of the restorative dentist more satisfying and profitable. In addition, the clinician can provide healthier restorations, with fewer complications and for less money than the CAD/CAM option. How can supragingival dentistry make direct composite techniques faster, yet still offer the highest quality and healthier options for our patients? Let’s now consider some modifications to the standard technique.
A Fast and Effective Anesthetic Technique
By using the Ruiz subperiosteal anesthetic technique (see the video “Subperiosteal Anesthesia Technique” on dentistrytoday.com) we can start the preparation of mandibular teeth in less than 2 minutes after the injection, and the patient will experience less post-op pain. This technique uses Articaine (1:200,000 epinephrine) to minimize tachycardia and the blanching of the tissues. The first injection is done below the muco-gingival line on the tooth to be treated, depositing one-third carpule slowly to ensure a painless injection (Figure 2). This is followed by one-third carpule deposited on the mesial papilla (until it blanches slightly) and then one-third carpule deposited on the distal papilla (until it blanches). Tissues should never completely lose the pink color, or else sloughing can occur (Figure 3).
Supragingival Preparation Design
Preparing a simplified, minimally invasive, healthier preparation design is faster than preparing a traditional proximal box, and it is based on the universal principles of supragingival dentistry (Table 2). The small-to-medium Class II preparation starts by using a FenderWedge (Directa Dental). This is done to protect the adjacent tooth from injury during the preparation, and it also makes the preparation much faster. The FenderWedge allows the clinician to remove the caries and perform the preparation much faster, as the concern of harming the adjacent tooth is nullified. Using a 1556 carbide bur, enter the tooth to find the caries through a small hole on the marginal ridge, sinking the bur 3.0 mm, then pushing toward the proximal to break contact with a 2.0-mm proximal opening (Figure 4). This small, tunnel-shaped preparation is usually still inside the contact area, not creating clearance.
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From this basic external outline, extend apically only to remove decalcified enamel. Using CARIES DETECTOR (Kuraray America), it is easy to identify and completely remove demineralized, infected dentin while preserving the external enamel outline, especially in the cervical region. When finished, the external enamel outline will be smaller than the internal, hollowed-out outline and will include some enamel without dentin support. Preserving that unsupported enamel is clinically acceptable, as current research shows that unsupported enamel can be repaired and will regain strength once a properly bonded composite is placed.5 There is no real clinical benefit to preserve unsupported occlusal enamel, so remove this tooth structure as needed. Doing this also allows for better visualization during caries removal to preserve the facial; lingual; and, especially, gingival enamel. One must make every effort to preserve cervical enamel and to maintain a supragingival restorative margin (a technique called Supragingival Enamel Margin Preservation)6 (Figure 5).
Simplified Matrix Protocol
When the tooth preparation is small and still in contact with the adjacent tooth (as described above), placing a segmental matrix can be a bit challenging. As a result, the clinician often struggles to place the matrix, sometimes giving up to then make larger cavities and break contact. In an effort to simplify this technique, the author worked to design a simplified matrix system with the help of Garrison Dental Solutions, which distributes the FenderWedge and invented Teflon-coated matrix bands. While I was describing my idea, the company informed me that Directa Dental was designing the FenderMate, a matrix band attached to a wedge (Figure 6), making matrix placement and wedging easier.
With the current version of the FenderMate, it is important to do the bonding procedure before placing it, as the modern adhesives will bond to the metal matrix band. While I’m still working on modifications for a newer version of the product with Garrison Dental Solutions and Directa Dental, this current combination of FenderWedge and FenderMate makes preparing and restoring small-to-medium Class II much faster and less stressful.
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| Figure 4. A tunnel-shape preparation using FenderWedge (Directa Dental). | Figure 5. Observe the unsupported enamel in the gingival floor following dentin caries removal. |
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| Figure 6. The FenderMate (Directa Dental), used without the ring. | Figure 7. The curing light created gaps during polymerization. |
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| Figure 8. The Ruiz 1 instrument (acorn shape) (The Los Angeles Institute) was used to develop deep morphology. | Figure 9. Since the patient was anesthetized using the subperiosteal technique, preparation began within 2 minutes. |
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| Figure 10. Using a FenderWedge for tunnel preparation. | Figure 11. Applying CARIES DETECTOR (Kuraray America) to ensure caries removal. |
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| Figure 12. The FenderMate, used with its ring. | Figure 13. Removing flash using a #12 blade. |
The Importance of Using a Quality Bulk-Fill Material
The use of a quality bulk-fill composite material (such as Bulk EZ bulk-fill composite [Zest Dental Solutions]) accelerates the filling procedure and makes it more predictable. This material choice minimizes the effects of polymerization shrinkage, which leads to open margins and post-op sensitivity. After the self-etch bonding procedure is completed, carefully fill the entire cavity with the bulk-fill composite to right below the enamel level and wait 90 seconds for the self-curing process to occur. At this time, do not use the curing light so as to minimize the effects of polymerization shrinkage (Figure 7). After 90 seconds, the Bulk EZ will be hard; then, still without curing, place the final occlusal increment using a restorative composite with good wear characteristics (such as Admira Fusion [VOCO America]) over the entire occlusal surface. Before curing the occlusal layer, use the Ruiz 1 instrument set (Dr. Ruiz’s All-Purpose Composite Instruments [The Los Angeles Institute]) to develop a nice deep morphology, and then light cure (Figure 8).
CASE REPORT
Diagnosis and Treatment Planning
A female patient presented with a small-to-medium interproximal caries on a mandibular second bicuspid that was detected on her periodic radiographic checkup. The patient was treatment planned for a direct Class II composite restoration. An informed consent form was presented to, and signed by, the patient. A 30-minute appointment was then set up for the procedure.
Clinical Protocol
The patient was anesthetized using the Ruiz subperiosteal anesthetic technique (Figure 9). (A free video depicting this technique is available at ruizdentalseminars.com.) After placement of a FenderWedge, the tooth was prepared using a minimally invasive supragingival protocol, creating a small external cavity outline that was 2.0 mm wide at the proximal contact, 3.0 mm deep cervically, and expanding internally (Figure 10). As a part of the preparation process, a caries detector (CARIES DETECTOR [Kuraray America]) was used to ensure the complete removal of any caries and to preserve healthy tooth structure (Figure 11). Immediately after tooth preparation was completed, the tooth was isolated (DryShield [DryShield]) to avoid moisture contamination.
With the FenderWedge still in place, the enamel was carefully etched using phosphoric acid gel (Ultra-Etch [Ultradent Products]) for 10 seconds, being careful to just etch the external enamel (cavo-margin) extending to the uncut enamel and to avoid etching the dentin. The tooth was rinsed with air-water spray and dried with air until the enamel looked frosty. There was no concern of overdrying the dentin, as it was not etched or demineralized as it would have been in a total-etch technique.
The primer (bottle 1 from the CLEARFIL SE PROTECT self-etch bonding system [Kuraray America]) was applied to the previously dried tooth for 25 seconds. This bonding system has the monomer MDPB, a strong bactericide. If a different bonding system is used, it is important to disinfect the cavity with an efficient disinfectant (such as GLUMA Desensitizer [KULZER]), followed by the self-etch bonding system. After the primer was in place for 25 seconds, the solvent from the primer was evaporated by using a medium stream of air until the primer visibly stopped moving. A thin layer of hydrophobic adhesive resin (bottle 2 from CLEARFIL SE PROTECT) was applied, air thinned, and fully light cured.
Next, the FenderWedge was replaced with the FenderMate, which can be done with or without the ring (Figure 12). The bonding procedure should not be done with the WedgeMate in place, as the composite may bond to the metal matrix band and, during matrix removal, pieces of the margin or the marginal ridge may break. When the FenderWedge is removed, there may be some bleeding, especially if the switch is done too slowly. That is not a problem since the tooth has already been bonded and cured. If contamination occurs, fully wash the preparation with water and air; then fully dry and start the filling procedure.
The cavity-filling procedure started by applying a flowable composite (Admira Fusion Flow [VOCO America]) to only dentin first and then light-curing it (3-second cure VALO [Ultradent]). An effort was made to avoid touching enamel during the dentin lining because the polymerization-shrinkage forces would pull the composite toward the best-bonded surface. (If enamel and dentin are linked with the flowable, the flowable will pull toward the enamel and create a gap of dentin, which can cause post-op sensitivity.) A second layer of flowable was then placed on the enamel cavo-margin of the proximal preparation and cured.
An alternative to the above steps could be the use of a dual-cure, flowable bulk-fill material (such as Bulk EZ), as the dual-cure formulation of this composite allows for the bulk filling of a cavity without the negative effects of light-cure polymerization shrinkage.
A final layer of restorative composite (Admira Fusion) was then applied. Admira Fusion is the first purely ceramic-based restorative material that contains no BISGMA monomer. Thanks to VOCO’s Ormocer technology, it is more biocompatible, with low polymerization shrinkage (1.25% by volume), low shrinkage stress, high surface hardness, and resistance to discoloration. All the flash was removed with a few strokes of a #12 blade, using it with a 2-handed technique for safety (Figure 13). Next, the final cure was done, flooding the tooth with Liquid Lens (Zest Dental Solutions) or KY jelly and then light curing the material from the facial, lingual, and occlusal. An occlusal adjustment was done using a 2-color articulator paper (Arti-Fol [Bausch]) technique (watch a video on this technique at ruizdentalseminars.com).
The procedure was completed in little more than 15 minutes. The patient was satisfied, had no pain during the procedure, reported no postoperative discomfort on the tooth, and had only minor discomfort in the local anesthetic injection site.
CLOSING COMMENTS
The ability to provide patients with fast, high-quality, minimally invasive, supragingival, simple direct Class II composite resin restorations will serve to make patients and clinicians happy. More importantly, following the direct composite placement technique described herein will remove the temptation of using more aggressive and potentially unhealthy indirect restorative techniques.
References
- Thomas MS, Kundabala M. Pulp hyperthermia during tooth preparation: the effect of rotary instruments, lasers, ultrasonic devices, and airborne particle abrasion. J Calif Dent Assoc. 2012;40:721-731.
- Waerhaug J. Presence or absence of plaque on subgingival restorations. Scand J Dent Res. 1975;83:193-201.
- Müller HP. The effect of artificial crown margins at the gingival margin on the periodontal conditions in a group of periodontally supervised patients treated with fixed bridges. J Clin Periodontol. 1986;13:97-102.
- Pallesen U, Qvist V. Composite resin fillings and inlays. An 11-year evaluation. Clin Oral Investig. 2003;7:71-79.
- Eidelman E. Composite resin support of undermined enamel in amalgam restorations. Pediatr Dent. 1999;21:118-120.
- Ruiz JL, Finger W. Enamel margin preservation and repair technique. J Dent Res. 2016;95(special issue 5). Abstract 2370749.
Dr. Ruiz practices in Los Angeles, and he is the director of the Los Angeles Institute of Clinical Dentistry and of many continuing education courses at the University of Southern California. He is an associate instructor at Dr. Gordon Christensen’s Practical Clinical Courses in Provo, Utah, and an independent product evaluator for CR Foundation, also in Provo. He can be reached at (818) 558-4332 or via email at ruiz@drruiz.com.
Disclosures: Dr. Ruiz reports no disclosures.
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