Effect of Resin Cement Mixing Method on the Retention Strength of a CAD/CAM Zirconia Crowns

Abstract

Several treatments have been suggested to improve the retention of zirconia-based restorations luted with different cements. Resin cements are believed to improve crown retention under certain circumstances. The aim of the present study was to examine the effect of three cements with different mixing methods on the retention of CAD/CAM zirconia crowns. Thirty extracted human molars were randomly divided into three groups and prepared for all-ceramic crowns (6° taper, 4-mm height and a 1.2 mm rounded shoulder finish line). A zirconia crown (Tizian CAD/CAM) was fabricated for each tooth. The crowns were air-abraded using airborne particles, adjusted, and cemented to the corresponding tooth with one of the following cements: Panavia F2 (PAN group), RelyX Unicem (UNH group) or RelyX Unicem Aplicap (UNA group). After 3,000 rounds of thermal cycling, retention was measured using a specific retentive jig and a universal testing machine. The retention strength was measured by dividing the retention force by the surface area of each tooth. The means of the pull-out test results for each group were compared using analysis of variance and Tukey's HSD test (α = 0.05). The mode of failure was examined using a stereomicroscope. The mean retention value was 6.45 (0.34) MPa for the UNA group, 4.99 MPa (0.47) for the UNH group, and 4.45 (0.39) for the PAN group; the differences among the three test groups were significant. A mixed failure was observed in 83.3 % of specimens, while no cohesive failure occurred in the crowns. Within the limitations of the present study, of the three tested cements, Relyx Unicem Aplicap cement was associated with the highest retention force for Tizian zirconia crowns.

Comparison of Retention and Fracture Load of Endocrowns Made from Zirconia and Zirconium Lithium Silicate After Aging: An in-Vitro Study

“…On the other hand, restorations in Zr group did not bene t from the adhesive bond of resin cement as much as restorations in ZLS group did. Sadighpour et al showed 279.19 N ±50.14 retention force in zirconia crowns sandblasted with aluminum oxide particles and cemented with Panavia F2.0 dual cure resin cement which is approximately similar to the retention force in Zr group in the present study (271.50 N ±114.31) [34].…”

“…2). The failure modes were classi ed as type 1 for cohesive failure of cement layer, type 2 for adhesive failure at the cement-tooth interface, type 3 for adhesive failure at the cement-restoration interface, and type 4 for mixed failures [34].…”

Comparison of retention and fracture load of endocrowns made from zirconia and zirconium lithium silicate after aging: an in vitro study

“…3 ). Failure modes were classified as type 1 for cohesive failure of cement layer, type 2 for adhesive failure at the cement-tooth interface, type 3 for adhesive failure at the cement-restoration interface, and type 4 for mixed failures [ 41 ].

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The effect of a zirconia primer on the shear bond strength of Y-TZP ceramic to three different core materials by using a self-adhesive resin cement

“…[ 8 ] Whereas, the glass-free polycrystalline microstructure of zirconia ceramics does not allow such reaction. [ 9 ] Resin cement–zirconia bond can be improved through various methods such as the micromechanical means of airborne-particle abrasion[ 10 11 12 ] or chemical activation with specific monomers such as 10-methacryloyloxydecyl dihydrogen phosphate (MDP) and 4-methacryloxy ethyl trimellitic anhydride. [ 13 14 15 16 17 ]…”