Effects of abutment diameter, luting agent type, and re-cementation on the retention of implant-supported CAD/CAM metal copings over short abutments

Abstract

PURPOSEThe aim of this study was to evaluate the effects of abutment diameter, cement type, and re-cementation on the retention of implant-supported CAD/CAM metal copings over short abutments.MATERIALS AND METHODSSixty abutments with two different diameters, the height of which was reduced to 3 mm, were vertically mounted in acrylic resin blocks with matching implant analogues. The specimens were divided into 2 diameter groups: 4.5 mm and 5.5 mm (n=30). For each abutment a CAD/CAM metal coping was manufactured, with an occlusal loop. Each group was sub-divided into 3 sub-groups (n=10). In each subgroup, a different cement type was used: resin-modified glass-ionomer, resin cement and zinc-oxide-eugenol. After incubation and thermocycling, the removal force was measured using a universal testing machine at a cross-head speed of 0.5 mm/min. In zinc-oxide-eugenol group, after removal of the coping, the cement remnants were completely cleaned and the copings were re-cemented with resin cement and re-tested. Two-way ANOVA, post hoc Tukey tests, and paired t-test were used to analyze data (α=.05).RESULTSThe highest pulling force was registered in the resin cement group (414.8 N), followed by the re-cementation group (380.5 N). Increasing the diameter improved the retention significantly (P=.006). The difference in retention between the cemented and recemented copings was not statistically significant (P=.40).CONCLUSIONResin cement provided retention almost twice as strong as that of the RMGI. Increasing the abutment diameter improved retention significantly. Re-cementation with resin cement did not exhibit any difference from the initial cementation with resin cement.

Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study

“…It could be shown that the pairwise comparisons had a post-hoc effect power ranging between 84% and 99%. The aging of the tested specimens for retention force evaluation was performed with HS and HTS that made the present study comparable to similar investigations [ 27 , 44 , 45 , 46 ]. Data from the present study clearly demonstrated that the bonding capacities of the various luting materials had a remarkable influence on the retention force only after the first cementation.…”

“…Mundt et al [ 30 ] used a similar sandblasting model of the cobalt–chromium crown inner surfaces with 50 mm particle size aluminum oxide at a pressure of 2.5 bar, followed by rinsing and drying, reporting similar observations. However, an in vitro study investigating the retention of implant-supported CAD/CAM metal copings after cementation with temporary cements and recementation with the permanent resin cement Panavia showed that the bond strength of the adhesive resins was not affected after minor surface alterations occurring during recementation [ 46 ]. The differences in the results can be explained by different study designs: the initial cementation was performed with temporary cement; however, the recementations were performed with temporary resin cements.…”

Influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with a lingual slot

“…The evaluation of retention of general prostheses is a method of measuring the pull force using a universal testing machine. 20 21 22 23 However, in this study, cement-retained implant prostheses with RCS measured force removed through lingual slots. These differences should be considered.…”

“…The results of this study show that the retentive force increases as the abutment height increases, and it is predictable that the surface area of abutment may also be affected. Previous studies 20 21 have suggested that abutment height has a significant effect on the resistance to removal. However, according to a follow-up study by Covey et al, 22 abutment height may be positively related to retention strength, but abutment's total surface area is not.…”

“…In a study by Abbo, 20 the height of the implant abutment was estimated a relatively low removal force was observed at a 5.5 mm abutment (124.89 N) than the 6.5 mm titanium abutment (198.09 N). In a study by Safari, 21 the height of the implant abutment was set at 4.5 mm and 5.5 mm, and the removal force decreased from 5.5 mm (460.44 N) to 4.5 mm (364.19 N). Similar to the results of various studies, this study also proved that the greater the abutment height, the greater the removal force.…”