The effect of fatigue damage on the force required to remove a restoration in a cement-retained implant system.
OBJECTIVE
To evaluate the luting agents and retentive forces before and after mechanical stressing.


METHODS
Sample size N was 12 for each group, and 12 Cera-One closed-end gold cylinders were cemented with three types of luting cements (ImProv, UltraTemp, and TempBond). The force required to remove the gold cylinders from the abutments was determined with an MTS testing machine. After cleaning and recementing the cylinders, the samples were placed in the housings of an Alabama-type three-body wear machine and load of 110 N was applied to the gold cylinders at a frequency of 80 cycles/min for 50,000 cycles. Then each cylinder was pulled from its abutment and the force at which the failure occurred was recorded. The procedure was repeated with 300,000 cycles.


RESULTS
Statistical analysis arising from two-way ANOVA found that the forces required to remove the abutments were significantly different. The most retentive cement was ImProv. Before cyclic loading, on average, ImProv produced a retentive value 85% higher than that yielded by TempBond, and 25% higher than that of UltraTemp. The three cements were significantly different at each of the three cycle levels.


CONCLUSIONS
These results might suggest TempBond luting agent as the material of choice for provisional cementation because it allows easier removal of the prosthesis and maintains enough retention to prevent loosening of the restoration. The clinical implication is that the effect of cyclic load on the strength of the cements is different, an important factor in selection of a cement. ImProv had the highest retentive value before and after the two cycles, and TempBond had the lowest. UltraTemp had the highest percentage of retentive value lost. TempBond had no significant loss under loading even though initially it was the weakest.
Kaar
Darian
D
Graduate Prosthodontics, Indiana University School of Dentistry, Indianapolis, IN 46202-5186, USA.
Oshida
Yoshiki
Y
Andres
Carl J
CJ
Barco
M Thomas
MT
Platt
Jeffrey A
JA
D000180:Acrylic Resins; D000704:Analysis of Variance; D002484:Cementation / Q000379:methods; D000044:Dental Abutments; D003738:Dental Cements; D017005:Dental Debonding; D017268:Dental Prosthesis Retention / Q000379:methods*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D008422:Materials Testing; D008899:Mineral Oil; D011897:Random Allocation; D015034:Zinc Oxide
D000180:Acrylic Resins; D003738:Dental Cements; C413303:ImProv; C474196:Tempbond NE; C491449:ultratemp firm; D008899:Mineral Oil; D015034:Zinc Oxide