By Anthony LaVacca, DMDThe success of indirect restorations is determined by a number of factors that include preparation, design, accurate impression making, high-quality precision laboratory fabrication of the restoration, and the technique and material used for luting the final restoration or prosthesis. Preparation design for crowns and bridges must consider adequate occlusal clearance and interproximal space for the restorative material and luting cement, divergence, and form for retention, ferrule, and the biologic width and margin placement. In turn, accurate and dimensionally stable impressions are essential for precise fabrication of the restoration.Luting cements used with indirect restorations have ranged from 1st generation cements such as zinc phosphate to glass ionomers to composite resins to resin-modified glass ionomers to self-adhesive resin composites. Traditional advantages of glass ionomers include their ability to chemically self-adhere, hydrophilicity, which enables setting of the glass ionomer in the presence of moisture, marginal seal, reduced sensitivity, and fluoride release over time. In the case of composite resin luting cements, traditional advantages have included superior esthetics and strength as well as the ability to utilize next generation self-etching technology. Since its introduction, I have been using G-CEM™ Automix self-adhesive resin cement, which combines the best of both worlds by offering the benefits of the 7th generation resin self-adhesive technology found in G BondTM as well as glass ionomer luting cements in one product. G-CEM™ Automix self-adhesive resin cement contains self-etching composite resin technology and self-adhesive hydrophilic glass ionomer technology. While clinically I have found other luting cements to offer excellent results, G-CEM™ has brought the scientific foundation and clinical application of luting cements to a new level. It offers superior handling, ease-of-use, strength, and excellent esthetics. The low film thickness and fluidity of G-CEM™ help ensure cement coverage over the whole of the preparation area and accurate seating of the restoration, while its high bond strength aids retention and provides for an excellent marginal seal. Dual-cure chemistry enables tack curing of the cement prior to full curing.In addition, G-CEM™ offers fluoride release, reduced sensitivity, and moisture tolerance during application and setting that is typically associated with glass ionomer cements. The recent introduction of G-CEM™ Automix has enhanced its ease of use. The automix tip results in even mixing of the components prior to direct application of the mixed cement from the mixing tip to the restoration. This is quicker, easier, and reduces cleanup.
Fig. 1 — G-CEM™ Automix The step-by-step case below shows the ease of use and excellent results obtained with G-CEM™ Automix.The patient presented with a fractured restoration in the upper right first molar and a carious lesion distally and occlusally in the adjacent bicuspid. The patient desired esthetic restorations and elected to have an all-ceramic zirconium crown and a direct composite in the bicuspid. After caries removal and completion of the preparation and buildup in tooth No. 3, gingival retraction was achieved and impressions taken. At the same appointment, the caries was removed from tooth No. 4, and indirect temporary composite (Voco) restorations were placed on both teeth using polycarboxylate cement (Durelon) and Vaseline. Subsequently, models and a die were poured and the laboratory fabricated the all-ceramic crown.
Figs 2a and 2b — Model and die for indirect restoration fabrication
Figs. 3a, 3b, and 3c — All-ceramic crownAt the seating appointment, the temporary restorations were removed, the preparations cleaned, and retraction cord placed for exposure of the margins during placement of the restorations. G-CEM™ Automix was applied directly to the internal aspect of the all-ceramic crown from the mixing tip. The restoration was then gently seated, held in place under pressure, and tack-cured in position for four seconds. Excess cement was easily removed using an explorer and a Microbrush while maintaining pressure, and final light-curing was performed to the manufacturer’s specifications. The cement was allowed to continue to self-cure for an additional four minutes. This was followed by removal of the retraction cord. The end result was a highly esthetic restoration and a delighted patient.
Fig. 4 — Preparation free of debris, with retraction cord in position
Figs. 5a and 5b — Application of G-CEM™ using the G-CEM™ Automix mixing tip
Fig. 6 — Seated restoration
Fig. 7 — Removal of excess cement
Fig. 8 — Final, esthetic all-ceramic crownFor more information about G-CEM™ Automix, click hereAcknowledgmentThe author would like to thank Procerex for fabrication of the all-ceramic zirconium crowns shown in this case.
Anthony LaVacca, DMD, a certified prosthodontist, practices in Naperville, Ill. Dr. LaVacca offers his patients comprehensive care for dental implants, cosmetics, restorative, and general dentistry. He lectures nationally and internationally. Contact him by e-mail at [email protected].