This laboratory study evaluated the use of resin primers and adhesives that are used to prevent postcementation sensitivity, to see if there is any effect of these desensitizing agents on the retention of full crown restorations.Materials and Methods:
Thirty extracted human molar teeth were mounted in molds using self-cure acrylic using a surveyor to position the long axis of the crown to that of the mold. The specimens were prepared for full crown coverage using a specially designed apparatus to create standardized preparations. Each tooth was prepared with an axial wall height of 4 mm and a taper of 2.4 per wall with a 1.5 mm axial tooth reduction. Full crown patterns were waxed directly on the teeth with an attachment fabricated and full crowns were fabricated in a silver-palladium casting alloy. The castings were abraded with 50-μm aluminum oxide, tried on the teeth, and adjusted for proper fit.Materials and Methods:
Ten of the teeth were treated with One-Step, which is an etch-and-rinse one-bottle (primer + adhesive) bonding agent and 10 with Gluma Desensitizer; the remaining 10 were left as untreated controls. The crowns were cemented with zinc phosphate cement and stored for 24 hours in water at room temperature.Materials and Methods:
The castings were placed on a universal testing machine in such a manner as to be parallel with the directional axis of draw. With a crosshead speed of 0.5 mm/minute, a tensile force was applied to the casting until the cement failed and the load at failure was recorded in Newtons.Materials and Methods:
The crowns and teeth were cleaned and the surfaces were lightly roughened with the surfaces retreated as above. This process was repeated with an encapsulated conventional glass ionomer luting cement (Fuji I, GC America, Alsip, IL) and then with a resin-modified glass ionomer cement (Vitremer Luting Cement, 3 M ESPE).Results:
The crowns cemented with the conventional glass ionomer and resin-modified glass ionomer cement had significantly higher retention values than those cemented with zinc phosphate cement. There was no statistically significant difference for the retention with or without the desensitization step.Conclusion:
This study demonstrates that the use of a resin primer or an adhesive system has no effect on the retentive properties of three different types of luting cement.