Go with the flow

THE SET-UP

"Fractured ceramic crowns are an everyday problem in dental practice. It is not always feasible or cost effective to replace the ceramic restoration for the patient if a repair can be made using composite resin. In this article, a new self adhering flowable composite, Vertise Flow, will be used to demonstrate a simplified approach to porcelain repair that does not require the use of Hydrofluoric acid or silane priming."
-Dr. Robert A. Lowe, team lead

The need to repair broken ceramic restorations is a common occurrence in the dental practice. It is not always cost effective, for the patient or the dentist, to replace the ceramic restoration if the restoration can be predictably repaired with composite resin. If the fracture is minimal, and there is available porcelain and /or tooth to bond to, the repair often can be done using composite resin.

There are many steps involved in preparing the fractured surface before composite placement. Using hydrofluoric acid (HF) to sufficiently etch ceramic traditionally has been required to prepare the ceramic surface to adequately adhere to dentin adhesives that are typically used to place composite. HF is very caustic to the tissues and must be used with extreme caution. The challenge is to limit the HF to the ceramic and make sure it doesn’t come in contact with the gingival tissues or tooth substrate. After etching the ceramic, silane couplers traditionally are applied to increase the adhesive’s bond strength to the ceramic. The fractured area is ready to accept the composite resin repair only after careful preparation of the ceramic and tooth surface.

Kerr Corp.’s Vertise Flow, a revolutionary new material, is one of the latest advances in composite resin technology available to dentists. This “self adhering” composite resin is designed to combine the etch, rinse, bond and flowable liner steps in placing composite resin restorations into one easy step. During the development of this technology, Bui, Nguyen, Qian, and Tobia1 tested the efficacy of using Vertise Flow to bond composite to ceramic with and without conventional surface preparation using HF and silane coupling agents. Their study concluded it offered effective bonding to porcelain substrate without HF or silane, simplifying the clinical process of ceramic repair for the dentist.  

The following are two clinical cases that demonstrate the technique.

Clinical case No. 1: A Class IV incisal fracture of a ceramic veneer

Fig. 1 is a pre-operative view of a Class IV distal ceramic fracture of a porcelain veneer on tooth No. 24. This type of fracture can occur during lateral excursions and can be in part due to a “cross over” lateral interference, a sharp distal-incisal preparation angle, or a traumatic accident. As seen from the incisal view, this fracture is entirely in ceramic (Fig. 2). The fractured edge is prepared using a course diamond to create a 2 to 3 mm bevel from incisal edge to proximal surface (Fig. 3).

If available, air abrasion can be used to enhance micromechanical adhesion to the ceramic. A course diamond also works. A dead soft matrix strip is used on the proximal side opposite the fracture to isolate the operative area. On the side of the repair, Tapetrix Matrix Tape (Novadent) is used to isolate. Because you can stretch this tape very thin and create a small, elliptical window for composite contact, this works well when restoring proximal contacts in anterior Class 3 and Class IV situations. 

Vertise Flow is dispensed (Fig. 4) and then brushed onto the prepared ceramic surface making sure to agitate and saturate the beveled area of porcelain (Fig. 5). After light curing for 20 seconds, Kerr’s Herculite Ultra is used in shade matching the existing porcelain and to rebuild the tooth’s missing disto-incisal corner. Herculite Ultra, designed for a mono-layering technique, eliminates the need for a complex build up for such a small restoration and creates a beautiful chameleon effect with the surrounding porcelain. The nano hybrid composite is applied and sculpted with a composite plastic filling instrument such as Hu-Friedy’s Goldstein Flexithin Mini 4 (Figs. 6 and 7).

Once the composite is placed and light cured for 20 seconds, the contouring and finishing process can begin. Flexible composite finishing discs (OptiDisc from Kerr Hawe) are used, first in medium then fine grits to contour the composite repair and refine the marginal interface. It is very important to use water spray and make sure the OptiDisc is rotating from the composite material toward the ceramic surface to create an “invisible” transition from restorative material to ceramic (Fig. 8).  Next, 30 micron diamond interproximal finishing strips (Axis Dental) are used to contour and refine the restoration’s proximal marginal contour (Fig. 9). Be careful to use this strip apical to the contact area only. Aluminum Oxide polishing strips (GC America’s Epi-tex) will further polish the restoration’s proximal surface and not remove the contact area (Fig. 10). Polish the composite’s surface with rubber abrasive discs, again making sure the disc rotation is toward the ceramic surface (Fig. 11).

The final polishing step is completed with an Occlubrush cup, from KerrHawe, without water spray. The occlubrush will impart a beautiful luster to the composite resin (Fig. 12). A surface sealant (Kerr’s Optiguard) is applied, air thinned and light cured for 20 seconds (Fig.13). The purpose of the surface sealant is to microscopically seal the interface between the composite and the porcelain and to help guard against staining. Fig. 14 shows the completed ceramic repair using Vertise Flow and composite resin. Comparing this with the pre-operative view in Fig. 1, it is difficult to see a composite repair has been performed.

Clinical case No. 2

The patient in Fig. 15 had a porcelain fracture in the cervical region of a porcelain veneer on tooth No. 10. Because it is difficult to match a single veneer from a laboratory standpoint, one option is to repair the affected area with a composite resin. The surface of the tooth structure and about a 2 mm area of porcelain incisal to the fracture line is treated with an air abrasion device with 50 micron particles of aluminum oxide powder (Fig. 16). This creates a micromechanically roughened surface to increase the quality of the composite resin’s bond to the tooth.

After rinsing away the aluminum oxide (Fig. 17), it is common to have a little hemorrhage secondary to gingival abrasion (Fig. 18). Kerr’s Hemostasyl is an astringent material used to eliminate the gingival hemorrhage and create a suitable environment for dental adhesive chemistry (Fig. 19). Its “mousse-like” viscosity allows the operator to confine the material to a localized area and keeps the astringent from dissipating from the area until it is rinsed away (Fig. 20).  


Next, Vertise Flow is dispensed onto the cervical area (Fig. 21) and dispersed over the tooth surface and porcelain that has been microetched using the brush (Fig. 22) that is included with the Vertise kit. Using this type of brush versus traditional microbrushes increases the material’s bond strength. This facilitates a more aggressive, intimate contact of the material to the tooth substrate, which allows a better interaction of the chemistry with the calcium ions in the dentin and phosphate groups in the adhesive monomers of the bonding system.

After light curing (Figs. 23 and 24) the appropriate shade of composite (Kerr’s Herculite Ultra) is placed over the cured Vertise in the cervical area to be restored (Fig. 25). After sculpting with a plastic filling instrument, a sable artist’s brush is used to blend the composite material (Fig. 26) and refine the margin interface between the composite and ceramic. After light curing, the composite material is contoured using carbide composite finishing burs from Axis Dental (Fig. 27) and OptiDiscs from KerrHawe (Fig. 28). Polishing is accomplished with rubber abrasive discs (Fig. 29) and completed with an Occlubrush, both from KerrHawe (Fig. 30). After an application of Optiguard surface sealant (Fig. 31), the completed porcelain repair is shown in Fig. 32.

Keep it simple

A technique for porcelain repair has been described that by using the characteristics of Vertise Self Adhering Composite to simplifiy the process, eliminating several steps, while producing an esthetically excellent clinical result.

Robert A. Lowe, DDS, FAGD, FICD, FADI, FACD, maintains a private practice in Charlotte, N.C. Dr. Lowe lectures internationally and teaches CE and dental training courses around the world on esthetic and restorative dentistry topics. He has worked with leading dental manufacturers as a clinical evaluator of new materials and products and has been published in several well-known dental journals. He can be reached at boblowedds@aol.com.