Da. Covey et al., Effects of abutment size and luting cement type on the uniaxial retention force of implant-supported crowns, J PROS DENT, 83(3), 2000, pp. 344-348
Statement of problem. The assumption that increasing the diameter of the ab
utment/crown components will provide greater resistance to crown loosening
forces than standard-sized components has not been reported either with cli
nical trials or in the laboratory.
Purpose. This study attempted to determine what effect abutment dimension a
nd type of luting agent have on the retention of the prosthetic crown.
Methods and material. Test specimens consisted of standard, wide, and "expe
rimental" CeraOne titanium abutments and matching CeraOne gold cylinders ce
mented with a zinc phosphate permanent or a zinc oxide eugenol provisional
cement. The mean uniaxial force (Newtons) and the load (MPa) required to di
slodge the cylinder from the abutment was determined. Statistical analysis
of the sample data was performed using a 2-way analysis of variance test (a
lpha = .05).
Results. Mean uniaxial resistance force (Newtons) was significantly greater
for zinc phosphate cement than for zinc oxide cement (P < .001). Abutment
size was a significant factor when permanent luting cement is used (P < .00
1). Retention strength per unit area (MPa) of the wide abutments was lower
than the standard size and "experimental" abutments.
Conclusion. Permanent luting cement produced uniaxial retention forces appr
oximately 3 times greater than provisional cement. The increase in surface
area provided by a wide abutment did not result in an improvement in retent
ion strength over the standard abutment.