Although it may be generally agreed that when a certain amount of tooth structure has been lost, a full crown is an appropriate restoration, this treatment option is not always feasible. Not every patient is in a financial condition to support the rehabilitative treatment prescribed by the practitioner. Patients might be between jobs or may have lost third-party coverage and are unable to obtain what is traditionally considered to be the “best” treatment. In such cases, alternatives must be made available to provide a functional restoration to these patients.
An example of this situation is described in the following case report. This case involves the use of a self-etch adhesive system and a microhybrid composite.
The patient was a woman who had lost what appears to have been a ceramic onlay-type restoration on her mandibular second molar (Figure 1). The patient was not covered by insurance, and her financial situation did not allow for a laboratory-fabricated restoration. Under those restraints, it was suggested that a large direct restoration be placed to regain functional use of the tooth. It was explained fully to the patient that a laboratory-fabricated full-coverage restoration was the best choice, and it was not certain how long a direct restoration would last, but it was clearly a better choice than no treatment.
|Figure 1. A tooth that once bore a partial-coverage ceramic restoration.||Figure 2. The preparation is complete. Bevels are placed around the periphery of the preparation.|
|Figure 3. An Automatrix and a Flexi Wedge are placed.||Figure 4. The Simplicity Universal Self-Etching Adhesive system|
The tooth was isolated with a rubber dam, as isolation is crucial for bonding procedures. The remaining restoration and luting medium were removed, and a slight bevel was placed around the margin periphery. (Figure 2) An Automatrix (Med-Thin, DENTSPLY Caulk) was placed to contain the restorative materials, and a Flexi Wedge (Common Sense Dental) was inserted interproximally (Figure 3). Simplicity (Apex Dental Products), a self-etching adhesive, was placed on the enamel and dentin. Simplicity is a universal self-etch adhesive system that truly etches enamel, with no sensitivity (Figure 4). It can be used with both direct and indirect systems, with light- and self-cured materials.
|Figure 5. The Simplicity Adhesive is placed and the entire pulpal floor is covered with a thin layer of Permaflo.|
Simplicity 1 was applied to both the dentin and enamel, gently rubbing it into the preparation for 10 seconds, and 3 coats of Simplicity 2 were then applied to the dentin and enamel. This was allowed to stand for 5 seconds, and then the preparation was gently dried for 5 seconds. A low-viscosity flowable composite (Permaflo, Ultradent), shade A4, was used to cover the entire floor of the preparation in a thin (0.5 mm) layer (Figure 5). Permaflo was chosen because of its dramatic radiopacity, which makes the margins of the restoration easy to discern on a radiograph. The adhesive and the flowable were light activated together for 10 seconds using an Ultralume 2 LED light (Ultradent). The adhesive and the flowable may be light activated independently
if desired, but with a light of strong intensity they may be done together. It is recommended that an activation time of 20 seconds be employed if using a halogen light with a power density less than 500 mW/cm2.
While the flowable is light activated, the matrix is held against the adjacent tooth with a burnisher and gentle pressure to ensure good contact (Figure 6). The tooth will be restored by using elements analogous to real tooth structure; ie, enamel composites and dentin composites. This “substrate-specific” restorative protocol represents a paradigm shift away from the usual method of simply applying different shades of the same kind of composites. The material used in this case was Vit-l-escence (Ultradent). The enamel shades of Vit-l-escence are more translucent, and the dentin shades are more opaque, as is the case in natural tooth structure. A rim of the Pearl Neutral shade of Vit-l-escence was placed and light activated for 10 seconds (Figure 7). Next, a layer of dentin shade A4 was placed in the central portion of the tooth and light activated for 10 seconds (Figure 8). Then the occlusal layer of enamel (Pearl Neutral) was placed on the preparation, achieving the desired cusp heights. The last increment was light activated initially for 5 seconds (Figure 9).
The matrix band was removed and the composite was contoured (Figure 10). Preliminary anatomy was placed (Figure 11) using the Kanca Posterior Kit from Brasseler (Figure 12). The rubber dam was removed, the occlusion adjusted, and final anatomy established (Figure 13). The surface luster was created through the use of a Jiffy Brush (Ultradent) on a dry surface at medium speed in a slow-speed handpiece. The tooth was then sealed by re-applying Simplicity to the entire tooth, and a composite sealer (Permaseal, Ultradent) was applied to the composite margins and air thinned. The restoration was completed by post-curing for 10 seconds per surface (Figure 14).
|Figure 6. An increment of Vit-l-escence resin composite is placed. A burnisher is used to put gentle pressure on the matrix and establish the contact, and the increment is light activated.||Figure 7. The peripheral rim of Vit-l-escence composite is placed and light activated. An enamel shade is used.|
|Figure 8. The A4 shade of dentin is placed in the central portion of the tooth where the dentin normally would be located.||Figure 9. The remainder of the composite is placed and given an early cuspal shape. Once again, an enamel shade of the Vit-l-escence is used.|
|Figure 10. The wedge and matrix band are removed, and the restoration is contoured using discs.||Figure 11. Using the Kanca Posterior Kit from Brasseler, anatomy is developed rapidly in the restoration.|
|Figure 12. The Kanca Posterior Kit from Brasseler.||Figure 13. The occlusion is adjusted, and the final anatomy is established using the same kit.|
|Figure 14. The restoration is polished with Jiffy Brushes and sealed using Permaseal, a resin surface sealer.||Figure 15. This is an image of a dye penetration specimen, restored as described above, except that no surface sealer was used. It shows no leakage on any margins. The dentin is obviously sclerotic and the interproximal margin is subgingival. This is an aggressive test of the adhesive system.|
There is ongoing research examining these types of restorations on an in-vitro basis. Figure 15 depicts an extracted human tooth restored exactly as described (but not surface-sealed), and then placed in a dye for 24 hours. Note that there is no dye penetration along any of the interfaces, in spite of the obvious presence of sclerotic dentin and a subgingival margin. This is but one of many such specimens.
It cannot be said for certain how long a restoration such as the one described will last, but it is the author’s experience that restorations of this type can last for quite a long time (10 years). One benefit of this type of restoration is repairability. It would be a simple matter to repair a portion of the restoration should it break over time. Should the microhybrid composite prove to be as durable as it promises, this type of restoration might develop into a standard choice in the expanding restorative armamentarium of adhesive dentistry.
Dr. Kanca maintains a private practice in Middlebury, Conn, with the emphasis on cosmetic dentistry. He has published over 50 original articles and abstracts in peer-reviewed journals such as the Journal of the American Dental Association, Journal of Esthetic Dentistry, Quintessence International, Journal of the Academy of General Dentistry, American Journal of Dentistry and the Journal of Dental Research. Dr. Kanca’s work has revolutionized the field of adhesive dentistry. He gave validation to etching of dentin with phosphoric acid, proved that resins can be used as pulp capping agents, discovered the concept known as wet-bonding, and has contributed significantly to the understanding of how resins attach to dentin. His latest work involves the best method of initiating light-activated resin composites in order to create the lowest interfacial stress, and has created the protocol known as “pulse activation.” He has received many honors, including the Gordon Christensen Award from the Chicago Dental Society, the Albert Knab Award from the Academy of General Dentistry, the William Gies Award from the First District Dental Society of New York, the Larry Pearson Award from the Connecticut State Dental Association, and the Outstanding Achievement Award from the American Academy of Cosmetic Dentistry. Dr. Kanca is an active member of the American Academy of Esthetic Dentistry and has lectured at every major meeting in the United States and around the world.
Disclosure: Dr. Kanca has a financial interest in Simplicity, but has no financial interest in any of the other materials described in the article.