Simplifying Posterior Restorations Using Self-Adhesive Systems

CHARACTERISTICS OF THE GLASS IONOMER
The GI, Fuji IX GP Extra, is a self-adhesive material that can be used with or without a cavity conditioner. By utilizing it without a cavity conditioner, there is a chemical adhesion between the cement and the hard tissues. This bond is achieved through an ionic exchange at the interface, resulting in an ion-enriched layer of cement that is firmly attached to the tooth structure. However, the use of a conditioner (Cavity Conditioner [GC America]) can provide an additional improvement in bond strength through micromechanical retention. This additional procedure uses a mild 10% polyacrylic acid to remove the smear layer and any other contaminants. And this preactivates the calcium and phosphate ions in the dentin in preparation for ion-exchange with the cement. This material has a coefficient of thermal expansion that is similar to dentin, which may improve marginal adaptation and resistance to microleakage at the restorative interface. Additional benefits of this material include improved translucency, high fluoride release, and can be bulk filled and finished in 2 and one-half minutes.

CHARACTERISTICS OF SELF ADHESIVE COATING
This self-adhesive resin coating (G Coat Plus) can provide a smooth surface with high gloss to the restoration. One report indicates that an application of this surface coating can provide a smooth glossy surface to GI and composite resin restorative materials. This International Association for Dental Research (IADR) study suggests that this coating can reduce the surface roughness value to 0.24 µm. This approximates the critical surface roughness value of 0.2 µm where no further bacterial accumulation or colonization is expected to occur. This coating technology improves the smoothness of the restoration by filling in the voids and surface irregularities from the material and finishing procedure. Another IADR study indicates that the coating allows for maturation of the chemistry of the GI by protecting it from the negative influences of the oral environment. Also, a study at the University of Illinois reports an improvement in the microtensile strength of the GI from the coating. In addition, since this self-adhesive coating bonds to tooth structure, this material has the potential of improving marginal integrity and reducing microleakage at the restorative interface.

Using these technologies in combination may improve the physical and mechanical properties and extend the clinical applications of this group of materials quite markedly. The clinical applications for this system include Class I, II, and cervical posterior restorations. Also, composite and amalgam replacements for nonloadbearing regions and in some clinical situations moderate occlusal loading provided that the restoration is well supported by surrounding tooth structure. In addition, this system is highly recommended for moderate to high caries risk patients using Caries Management by Risk Assessment.
Furthermore, it should be considered for use with any patient where there is a limited treatment time required such as pediatric, geriatric and special needs patients.

The ultimate goal of continuous material research and development is to enhance the practice of dentistry. Applications of GI technologies in dentistry have only approached the horizon with opportunities and possibilities for the future that can only be limited by our imagination. Although the long-term benefits of this self-adhesive system remain to be determined through long-term clinical studies, the recent findings suggest a promising future. The clinical illustrations demonstrate the utilization of this novel system to restore a carious lesion on the mandibular right first premolar.