Practice Solutions: Voco by Dr. Jose-Luis Ruiz

The past 30 years have brought great advances to dentistry. Nevertheless, dentists continue to find that some of the most common procedures, such as direct composite restorations, continue to be considerably time-consuming. Compared with traditional materials such as amalgam, direct composite restorations are often filled with complications—postoperatory sensitivity, marginal leakage and secondary caries, to name a few.

Additionally, all the great advances in dentistry haven’t yielded a great improvement in the health of the dental pulp. The number of root canal procedures has increased¹ in recent years, and periodontal health continues to be adversely affected by some restorative procedures, such as crowns with subgingival margins (Fig. 1).²

The ultimate goals of medical and dental technological advancements should be to yield true progress in improved health, fewer complications and predictable results and success.

Glass ionomers (GIs) and resin-modified glass ionomers (RMGIs) have a long history of success³ and can provide answers to some of the complications mentioned. Resin-based restorative materials and cements are excellent materials, but they do require perfect isolation and have poor cariostatic abilities, which make them very difficult or unpredictable in some situations, such as:

• direct restorations in areas where isolation is extremely difficult.
• cementation of subgingival restorations where isolation is virtually impossible, such as traditional crowns.
• for children and deciduous teeth, when moisture control and isolation is extremely difficult and maximum cariostatic abilities and fluoride release would be desirable.
• for geriatric patients.

A solution for direct restorations
GI materials including Ionolux and IonoStar Plus (Voco), Ketac Nano (3M) and Fuji II LC (GC America) have some unique characteristics. GIs and RMGIs are less sensitive to contamination than resin-based composites. GIs bond to both tooth structure and resin composites without the need for adhesives, and introduce less polymerization stress into the tooth structure than resin composites.⁴ GIs release fluoride into the adjacent tooth structure, and have a history of decreased marginal leakage and secondary caries.⁵

Post op sensitivity is rare, and the procedure is simplified and fast because it doesn’t require an adhesive. The above characteristics make GI materials ideal for direct restorations, especially in these cases:

• when isolation is compromised.
• when patients have a high caries index.
• certain health-compromised patients.
• geriatric patients.
• and within pediatric dentistry (Fig. 2).

An additional benefit of GI restorative materials is that they are a more biocompatible alternative for patients who might be allergic to resin-based composites, or are health-conscious and concerned with the (minor) possibility of the negative health effects of resin restorative materials.

Resin composites and monomers, which are mainly based on Bis-GMA, have some degradation and substances that may leach into the oral cavity. Restorative resins are cytotoxic before polymerization and immediately thereafter.

The use of self-etching, self-adhesive RMGI liners such as Ionoseal (Voco) and Vitrebond (3M) for direct restorations on deep dentin can significantly reduce postoperative sensitivity. RMGI liners are simple to use because no etching or bonding of the dentin is necessary, and their low module of elasticity⁶ reduces the effects of volumetric polymerization shrinkage.⁷ The technique to line and protect the deep exposed dentin with Ionoseal is simple and predictable—there’s no mixing required.

It’s a one-component, ready-to-use material that’s dispensed directly from the syringe. The liner is placed thinly only in the areas of deep dentin exposure, leaving a large amount of more superficial dentin and enamel to be receptive to stronger adhesion.

I don’t recommend the use of RMGI liners for indirect restorations, especially when a provisional will be used. There are times during the provisional removal when the lower adhesion liner bond can be disrupted.

Indirect restorations
RMGI materials, such as Ionolux and Meron Plus AC (Voco) and Rely-X Luting (3M), are ideal materials for indirect restorations.

As a clinician, I don’t recommend cutting teeth for crowns, because most teeth can be restored with supragingival, minimally invasive partial-coverage restorations such as onlays or veneers.⁸ The replacement of defective crowns is a regular occurrence in dentistry, and when doing so, it’s most common to have to deal with deep subgingival margins, which is quite complicated at the cementation stage.

Resin-based cements are contraindicated with subgingival margins because bleeding is usually difficult to control and isolation is virtually impossible. Resin cements are extremely sensitive to contamination, which can lead to microleakage, recurring caries and postop sensitivity.

RMGI cements are more forgiving to contamination, and thus ideal for the cementation of crowns with subgingival margins.⁹ They’re also easy to use, have better cariostatic abilities and release fluoride. (I’ve used Meron Plus AC for many years with excellent results.)

Finally, margin elevation is a great procedure when a true subgingival margin is present and the goal is to isolate and repair the damage. Treating the tooth with a minimally invasive partial coverage restoration (Figs. 3 and 4) is a great way to achieve desired results. It’s often a matter of preference whether margin elevation procedures are performed with bonded composite or RMGI. However, success is well documented when RGMI is used similar to an “open sandwich” procedure.

Conclusion
The goal of dentistry should be to provide healthier, more minimally invasive and durable restorative dentistry, with fewer side effects such as RTCs or gingival inflammation. The unique characteristics of GIs and RMGIs make them ideal for some situations where resin-based composites may not be smart solutions.

It’s wise for restorative dentists to have GIs and RMGIs as part of their full armamentarium.

1. aae.org/about-aae/news-room/endodontic-treatment-statistics.aspx
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