Effect of air-abrasion on the retention of zirconia ceramic crowns luted with different cements before and after artificial aging.
OBJECTIVE
The purpose of this in vitro study was to evaluate the effect of intaglio surface air-abrasion on the retention of CAD/CAM produced zirconia ceramic crowns cemented with three different types of cement. In addition the influence of artificial aging in masticatory simulator and thermocycling was tested.


METHODS
Extracted human premolars were prepared for all-ceramic crowns (12 degrees taper, 3 mm axial length). CAD/CAM zirconia crowns were manufactured. Half of the crowns were air-abraded with 50 microm alumina particles at 0.25 MPa, the rest was left as machined. The crowns were luted with zinc phosphate cement (Hoffmann), glass ionomer cement (Ketac Cem), or composite resin (Panavia 21), subgroups were either stored for 3 days in 37 degrees water bath or stored for 150 days in 37 degrees water bath, with additional 37,500 thermal cycles (5-55 degrees) and 300,000 cycles dynamic loading with 5 kg in a masticatory simulator. Then crown retention was measured in tension at a crosshead speed of 2 mm/min using a universal testing machine. Statistical analysis was performed with three-way ANOVA.


RESULTS
Mean retention values were ranged from 2.8 to 7.1 MPa after 3 days and from 1.6 to 6.1 MPa after artificial aging. Air-abrasion significantly increased crown retention (p<0.001), while artificial aging decreased retention (p=0.017). In addition, the luting material had a significant influence on retention (p<0.001) with the adhesive luting resin providing the highest retention.


CONCLUSIONS
The use of phosphate monomer containing composite resin on air-abraded zirconia ceramic can be recommended as most retentive luting method.
Shahin
Ramez
R
Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts-University at Kiel, Kiel, Germany. rshahin@proth.uni-kiel.de
Kern
Matthias
M
D020906:Air Abrasion, Dental; D000704:Analysis of Variance; D001732:Bite Force; D002484:Cementation; D017076:Computer-Aided Design; D003442:Crowns; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods; D006801:Humans; D008277:Magnesium Oxide; D008422:Materials Testing; D010710:Phosphates; D011076:Polycarboxylate Cement; D019279:Resin Cements; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013718:Tensile Strength; D015034:Zinc Oxide; D015036:Zinc Phosphate Cement; D015040:Zirconium
C093719:Panavia TPN-S; D010710:Phosphates; D011076:Polycarboxylate Cement; D019279:Resin Cements; D003776:Dental Porcelain; D008277:Magnesium Oxide; D015036:Zinc Phosphate Cement; C040235:Ketac-cem; D015040:Zirconium; C028541:zirconium oxide; D015034:Zinc Oxide