Comparative evaluation of casting retention using the ITI solid abutment with six cements.
OBJECTIVE
The purpose of this study was to test the retention of metal copings fabricated to fit on the one-groove, one flat-sided solid titanium abutment using six different cements.


METHODS
Ten hollow screw 3.8 mm ITI implants were mounted in acrylic resin blocks. A solid titanium abutment was placed on each implant and torqued at 35 Ncm. Prefabricated burn-out caps were placed on the titanium abutment and wax loops added to the occlusal surface to allow for subsequent retention testing. All plastic caps were embedded in phosphate-bonded investment and cast with noble alloy. Castings were inspected for surface irregularities using a stereomicroscope at 10x magnification. The six cements were: 1) eugenol-free zinc oxide (Temp Bond NE); 2) zinc-oxide eugenol (IRM); 3) zinc phosphate (Hy-Bond); 4) resin-modified glass ionomer (Protec Cem); 5) zinc polycarboxylate (Durelon) and 6) 10-methacryloyloxydecyl dihydrogen phosphate resin (Panavia 21). After cementation, implant-abutment-casting assemblies were stored for 24 h in 100% humidity. Samples were subjected to a pull-out test using an Instron universal testing machine at a crosshead speed of 0.5 mm/min. The load required to de-cement each coping was recorded and mean values for each group calculated. Means and standard deviations of loads at failure were analyzed using ANOVA and a Tukey studentized test. Statistical significance was set at P < or = 0.05.


RESULTS
The mean values (+/- SD) of loads in kilograms at failure (n = 10) for the various cements were as follows: Temp Bond 3.18 (+/- 1.1) (Tukey group D), IRM 9.25 (+/- 3.83) (Tukey group CD), HY-Bond 10.9 (+/- 6.52) (Tukey group C), Protec Cem 18.98 (+/- 6.23) (Tukey group B), Durelon 23.55 (+/- 4.29) (Tukey group B) and Panavia 21, 36.53 (+/- 8.1) (Tukey group A). Means with the same letter in the Tukey grouping are not significantly different.


CONCLUSIONS
The retention values of castings cemented to ITI solid abutments have not been reported in the literature. Within the limitations of this in vitro study, the results do not suggest that one cement type is better than another, but they do provide a ranking order of the cements in their ability to retain the castings. This ranking is somehow different than that obtained when the same cements are used on natural teeth. The material and surface characteristics of the implant abutment are likely responsible for this difference. Cement retention values obtained from studies that use teeth as abutments may be misleading when used in cement-retained implant-supported crowns. It is at the clinician's discretion to use a certain type of cement, based on the situation at hand.
Mansour
Ahmed
A
Division of Prsothodontics, University of Rochester Eastman, Department of Dentistry, Rochester, NY 14620, USA.
Ercoli
Carlo
C
Graser
Gerald
G
Tallents
Ross
R
Moss
Mark
M
D000704:Analysis of Variance; D002484:Cementation; D003188:Composite Resins / Q000737:chemistry; D000044:Dental Abutments; D001840:Dental Bonding; D003734:Dental Casting Investment / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry; D015921:Dental Implants; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D006813:Humidity; D008422:Materials Testing; D010165:Palladium / Q000737:chemistry; D011076:Polycarboxylate Cement / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013223:Statistics as Topic; D013997:Time Factors; D014025:Titanium; D019415:Torque; D015034:Zinc Oxide / Q000737:chemistry; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry
D003188:Composite Resins; D003734:Dental Casting Investment; D003738:Dental Cements; D015921:Dental Implants; D005899:Glass Ionomer Cements; D006047:Gold Alloys; D011076:Polycarboxylate Cement; D019279:Resin Cements; D015035:Zinc Oxide-Eugenol Cement; C449162:zinc oxide-non-eugenol cement; D010165:Palladium; D015036:Zinc Phosphate Cement; D014025:Titanium; D015034:Zinc Oxide