Consultants’ Comments

• “The few restorations that I placed early on lacked vitality and were more opaque; the overall esthetics improved as the lab became more familiar with 3M ESPE Lava.”
• “I have noticed a couple of delaminations of the veneering ceramic from the zirconia substructure.”

Description

3M ESPE Lava Crowns and Bridges

is a CAD/CAM system for anterior and posterior all-ceramic crowns and three- or four-unit bridges with a maximum span of 38 mm. Tooth preparation is similar to that for ceramic-metal restorations with a chamfer margin. Dies are scanned using a 3M ESPE Lava milling unit, followed by three-dimensional milling of the zirconium oxide framework. The framework is colored with one of seven available shades to coordinate with the final restoration. It is then overlaid with 3M ESPE Lava Ceram veneering ceramic. The zirconia ceramic provides high strength, while the overlay ceramic is designed for optimal esthetics. 3M ESPE Lava restorations may be cemented with traditional cements. This product received a 94% clinical rating.

Clinical Evaluation Protocol

• Sixty-six units were placed in 42 patients in 2003. These included single-unit crowns on six anterior teeth; 19 premolars; 29 molars; and four, three-unit bridges.
• All restorations were cemented with 3M ESPE RelyX Unicem Self-Adhesive Universal Resin Cement

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• Fifty-nine units were recalled at three years. These restorations included single-unit crowns on 25 molars, 16 premolars, six anterior teeth, and four, three-unit bridges.
• Restorations were evaluated on a 1-5 rating scale:
  1 = poor, 2 = fair, 3 = good, 4 = very good, 5 = excellent.

Clinical Observations

Resistance to Fracture/Chipping

Seven restorations exhibited slight chipping of the veneering ceramic. None were major in nature, but one necessitated replacement because it involved an anterior tooth. Eighty-one percent of the restorations rated excellent while the remaining 19% received ratings of very good and good. No fractures of the substructure were noted.

Esthetics

Sixty percent of the restorations had excellent shade match, and 20% received a very good or good rating. Twenty percent of the restorations that received a rating of good exhibited less vitality and more opacity. As the laboratories have become more familiar with the 3M ESPE Lava system, the vitality of the restorations have improved.

Microleakage

During the first three years of the evaluation, 20% of the restorations exhibited slight microleakage at the margins. The microleakage was characterized by minor graying at the margins. Eighty percent of the restorations exhibited no microleakage.

Wear Resistance

Eighty-one percent of the restorations exhibited no loss of gloss or wear at three years, while 19% exhibited a slight amount of wear.

Figure 1

Figure 2

Summary

The bar graph summarizes the findings of the

3M ESPE Lava recall at three years. The 3M ESPE Lava system received very good to excellent ratings for resistance to fracture/chipping (93%), microleakage (93%), wear resistance (93%), and a good rating for esthetics (88%).