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Know Your Adhesives, Trust Your Adhesives
The variety of adhesives, composite-resin materials, and resin cements on the market requires a high level of understanding and discernment.
The introduction and evolution of dental adhesives has clearly revolutionized the way dentistry is practiced. No longer limited to amalgam, gold crowns, and simple luting agents, we are now able to restore teeth esthetically, with strength and reliability. There has been a veritable explosion in the number and type of adhesives, composite-resin restorative materials, and resin cements. It is a formidable task to keep up with all of the choices available, to sift through manufacturers’ inevitable claims of product excellence, and to choose products and techniques to successfully address the myriad clinical challenges dentists face on a daily basis.
Clinicians typically develop a toolbox of techniques to treat routine procedures. Occasionally, however, one encounters a case where the presentation and circumstances encourage a more creative approach. The following case report illustrates just such a case.
Approximately 3 years ago, a 20-year-old woman was referred to the author by a local orthodontist. The patient had a significant skeletal malocclusion which made her a candidate for orthognathic surgery, but she and her parents were unwilling to undertake that treatment. Instead, they opted for a slightly less aggressive, novel approach to correct her malocclusion, called Wilckodontics, which combined surgery and orthodontics. The scope of this article does not permit a thorough discussion of the technique, but it involves scoring the cortical bone to accelerate tooth movement. Correction was not complete, but it did yield a dramatic improvement nonetheless. It was just prior to the onset of that treatment that the author was asked to see the patient for routine prophylaxis, restoration of multiple carious lesions, and oral hygiene instruction.
At her initial visit, the patient presented with the history of a traumatic fracture of tooth No. 9 some years before. It had been restored with a porcelain veneer; the restoration had “fallen off” after 8 weeks, and it had been restored again as an emergency procedure by direct-composite veneer. The patient was so anxious about the potential loss of this none-too-perfect composite build-up that she tearfully forbade the author and his team to clean or even physically examine the tooth. It was explained to the patient that if the connection of this composite veneer to the tooth was so tenuous it would be wise to replace it with something more secure, but she declined.
After treatment of carious lesions on 12 teeth, the patient underwent the orthodontic treatment. For whatever reason, she did not return for routine maintenance. Several years after the orthodontic treatment was complete, she underwent endodontic treatment of tooth No. 9 (a postoperative x-ray was sent to the author’s office), but the Cavit™ (3M ESPE, http://www.3mespe.com) temporary restoration in the endodontic access opening was never replaced. Murphy’s Law applied; it was no surprise when the patient frantically called on a holiday weekend to report the loss of that composite veneer (Figure 1).
Examination of the remaining tooth revealed that it would benefit from additional build-up for ideal support of the ceramic crown that was indicated pursuant to the endodontic therapy. The author explained to the patient that he could reattach the old composite veneer as a palliative treatment for the “esthetic emergency,” but that subsequently the tooth would require a core build-up to fill the access opening, followed by removal of the old veneer and placement of additional core material for the aforementioned rebuilding.
One system for bonding to old restorations of composite or even porcelain is Clearfil™ Repair Multi Purpose from Kuraray Dental (http://www.kuraraydental.com). It involves the use of a Ceramic Primer, one of the kit’s components, as a silane coupling agent to bolster the bond strength to ceramics and composites. After microetching the intaglio surface of the composite veneer with aluminum oxide, and acid-etching the enamel and veneer with phosphoric acid, the author applied the Ceramic Primer to the veneer. He then rebonded the veneer with a flowable composite, Clearfil™ Majesty Flow (Kuraray Dental), because of its exceptional mechanical strength. He then minimally reduced some of the great bulk of material (Figure 2).
When the patient returned for the definitive treatment, closer inspection revealed several additional concerns (Figure 3). First, the gingival level on tooth No. 9 was lower than the neighboring tooth No. 8. Second, the space for No. 9 was wider than the width of No. 8. This was bound to yield a square appearance of the new crown. The author tried to explain that crown lengthening tooth No. 9 and adding to the width of tooth No. 10 would render a more desirable outcome, but she flatly refused to undergo any surgery, and was unwilling to pay for anything but the one tooth she broke. The decision not to lengthen tooth No. 9 was a compromise the author could live with; he was less willing to compromise the outcome completely, and so he decided to bond tooth No. 10 at his own expense.
The first piece of the restorative puzzle was placement of a core build-up in the endodontic access opening. The author routinely uses Kuraray’s Clearfil™ Photocore light-cure composite resin core material because of its excellent properties. It cures to a depth of approximately 11 mm after 40 seconds in boost mode, thus allowing restoration in a single increment, and cuts like dentin (data on file, Kuraray Dental). However, when the author undertook this case, he had second thoughts. To get that depth of cure, the material had to be quite translucent. He did not want to use a material whose appearance would further complicate the difficult job of shade matching a single central incisor. He instead elected to use Kuraray’s Clearfil™ DC Core Automix, a dual-cure composite resin material that more closely matched the patient’s dentin shade, along with their dual-cure adhesive, Clearfil™ DC Bond. The dual-cure nature of these materials eliminates any concerns about depth of cure in the endodontic access opening (Figure 4, Figure 5, Figure 6).
As the author then prepared to remove the old composite veneer and place some more build-up material to create an ideal preparation, he began to question this approach. If he really trusted the efficacy of the adhesive used (Clearfil™ Repair) to attach the old composite, then why remove all the old material and replace it with new? Why not just prepare what he had to shape? That is ultimately what was done (Figure 7, Figure 8, Figure 9). To correct a slight discrepancy in the upper occlusal plane, tooth No. 10 needed to be slightly lengthened incisally. The patient’s bite would not allow this so the author essentially had to create a complete composite veneer for tooth No. 10 which lengthened the tooth, repositioned its incisal edge more labially, and widened the tooth mesially (Renamel® Microfill composite, Cosmedent, http://www.cosmedent.com; Clearfil™ SE Bond, Kuraray Dental) (Figure 10). A final vinyl polysiloxane impression was taken (Figure 11). The dentin shade was recorded with Ivoclar Vivadent’s (http://www.ivoclarvivadent.us) stumpfmaterial shade guide (Figure 12). Digital photographs were taken. A temporary crown was fabricated with Exacta Temp (Exacta Dental Direct. http://www.exactadental.com) and secured with TempBond® NE (Kerr Corporation, http://www.kerrdental.com). The patient was sent to the laboratory (Jurim Dental Lab, Great Neck, NY) to have a custom shade taken. The laboratory fabricated a crown of IPS® Empress (Ivoclar Vivadent). Upon its return, the crown was cemented with an esthetic adhesive resin cement system, Clearfil™ Esthetic Cement and DC Bond Kit (Figure 13, Figure 14, Figure 15).
In summary, it is important to have a thorough knowledge of the various adhesives, restorative materials, and resin cements, and their applicability to certain situations, and it is equally important to use materials whose track record engenders trust.
Dr. Rosenfeld has received material support from Kuraray Dental.
About the Author
Robert Rosenfeld, DDS
Westwood, New Jersey