A simplified approach to cementation of bonded restorations

Thanks to advancements in technology, dentists can now provide natural-looking bonded restorations quickly and easily. Digital technology can be used to design and mill restorations, and advancements in adhesive dentistry can be used to secure restorations. Historically, achieving that all-important, durable chemical bond between the tooth and the restorative material has been challenging. Problems have included selection of optimal cement, technique sensitivity, multistep procedures, and difficulty with clean-up of excess cement.

In the following case, we used a product containing new dual-monomer technology: a universal, self-adhering resin cement with a built-in silane coupling agent (LCSi). The cement was used to bond glass ceramic restorations to tooth structure and eliminate traditional adhesive challenges. Because of the product’s new technology, there was no need to apply a separate ceramic primer to the intaglio. This streamlined the cementation process. The cement also contained 10-methacryloyloxydecyl dihydrogen phosphate (MDP) adhesive monomer, which provides durable adhesion to dentin, enamel, metals, and zirconia. Because of this dual-monomer technology, the cement is indicated for the cementation of virtually all restorative materials.¹

The procedure was further simplified by a curing technology that provides a durable seal, yet at the same time forms a gel-like consistency, which makes cleanup easier. The product, Panavia SA Cement Universal (Kuraray Noritake), was used as described here to secure Vitablocs TriLuxe Forte (Vita North America) glass ceramic restorations. The restorations were created to restore form and function to the traumatically injured central incisors of a young patient.

Case summary

A 14-year-old female presented to our practice one year after a swimming pool accident. In the accident, she sustained traumatic injury to her central incisors (figure 1a). The oral examination showed that in addition to repairing broken incisal edges, treatment needed to take into account various factors. For instance, no. 8 required a necrotic nerve root canal, a post and core buildup, and full coverage. Additionally, no. 9 already had a large composite filling (figure 1b).

Figure 2: Preoperative digital impression with CEREC Primescan of both upper and lower arches — **Figure 2:** Preoperative digital impression with CEREC Primescan of both upper and lower arches

Clinical objective

The challenge was to achieve harmonic balance in the shape and form of these two teeth in the esthetic zone. This needed to be done in concert with the medically indicated treatment in the existing dentition.

Technique

Preoperative digital impressions of upper and lower arches were taken with a CEREC Primescan (Dentsply Sirona) intraoral scanner along with the corresponding buccal bite to register the occlusion (figure 2).

Figure 3: UniCore post and Clearfil DC Core Plus were used to create ferule effect on upper left-central incisor. — **Figure 3:** UniCore post and Clearfil DC Core Plus were used to create ferule effect on upper left-central incisor.

After completing a root canal, the buildup was begun using a UniCore post (Ultradent Products Inc.) and Clearfil DC Core Plus (Kuraray Noritake) to create the ferrule effect on the upper left-central incisor (figure 3).

Figure 4: Digital design — **Figure 4:** Digital design

After completion of a traditional tooth preparation for a CAD/CAM milled restoration (i.e., one that is smooth, round, and polished), an intraoral scan was performed. Restorations were then designed using CEREC Software 5.1 (Dentsply

Figure 5: Digital model of tooth preparation — **Figure 5:** Digital model of tooth preparation

Sirona; figure 4) based on digital models. The final restoration design was then sent to be milled (figures 5 and 6). The restorations fabricated from Vitablocs TriLuxe Forte ceramic block (feldspathic) were milled in the inLab MC XL (Dentsply Sirona) milling and grinding unit.

Figure 7: Stain and glaze using CZR pastes — **Figure 7:** Stain and glaze using CZR pastes

Figure 6: Digital model of final designs — **Figure 6:** Digital model of final designs

The restorations were finalized for shape, form, and texture using fine diamond burs, then stained and glazed using CZR pastes (Kuraray Noritake; figure 7). In addition, the Vita Smart Fire (Vita North America) oven was used for crystallization, glaze, stain, and corrective firing. Prior to final cementation, the restorations were tried in to check fit and esthetics.

Figure 8: Glass ceramic was treated with 10% hydrofluoric acid for 60 seconds. — **Figure 8:** Glass ceramic was treated with 10% hydrofluoric acid for 60 seconds.

Cementation procedure

Figure 9: Clearfil Universal Bond Quick was applied for 10 seconds to each preparation. — **Figure 9:** Clearfil Universal Bond Quick was applied for 10 seconds to each preparation.

Restorations were first treated with 10% hydrofluoric acid for 60 seconds (figure 8), after which they were thoroughly rinsed and air-dried. Of note, at this point in the procedure there was no need to apply a separate ceramic primer to the intaglio, as the proprietary long chain silane coupling agent (LCSi monomer) is built into Panavia SA Cement Universal.

Figure 10: A thin layer of Panavia SA Cement Universal (translucent shade) was injected into the restoration. — **Figure 10:** A thin layer of Panavia SA Cement Universal (translucent shade) was injected into the restoration.

Due to the patient’s occlusal relationship and short preparations, extra strength was indicated. Clearfil Universal

Figure 11: An LED curing light was used for a three-second tack-cure to harden the resin into a gel form. — **Figure 11:** An LED curing light was used for a three-second tack-cure to harden the resin into a gel form.

Bond Quick (Kuraray Noritake) was applied to each preparation for 10 seconds and thoroughly air-dried prior to the use of the cement (figure 9). A thin layer of Panavia SA Cement Universal (translucent shade) was then dispensed with a syringe into the intaglios of the restorations (figure 10). Again, there was no need for a separate priming step, as a silane coupling agent is built into the paste.²

Figure 12: An easy clean-up was facilitated. — **Figure 12:** An easy clean-up was facilitated.

Restorations were then seated, and an LED curing light was used for three seconds to harden the resin (figure 11). The excess cement, which forms a gel after light-curing, was easily removed (figure 12).

Figure 13: Final restorations — **Figure 13:** Final restorations

At the conclusion of the case, we were able to provide this young patient with an excellent esthetic and functional outcome while saving significant treatment and clean-up time (figure 13).

References

1. Masao I, Maruo Y, Nishigawa G, et al. Are shear bond strengths to modern ceramics and flexural strengths of resin cements correlated? Poster presentation. International Association for Dental Research conference. June 21, 2019.

2. Yoshihara K, et al. The silane-coupling effect of a silane-containing self-adhesive composite cement. Poster presentation. International Congress on Adhesive Dentistry conference. June 16, 2019.

Daniel Vasquez, DDS, graduated from La Universidad de Guadalajara in Mexico in 1989. He opened his private practice in Oceanside, California, in 1999. In addition to his doctorate degree in dentistry, he has completed special training in oral surgery, endodontics, dental implants, orthodontics, conscious sedation, and cosmetic dentistry at the Las Vegas Institute for Advanced Dental Studies.