Wear, microleakage and plastic deformation of an implant-supported chair-side bar system.
OBJECTIVE
This in-vitro study was designed to evaluate retention forces, microleakage and plastic deformation of a prefabricated 2-implant bar attachment system (SFI-Bar, Cendres+Métaux, Switzerland).


METHODS
Two SFI implant-adapters were torqued with 35 Ncm into two implant analogues. Before the tube bars were finally sealed, the inner cavity of the tube bar was filled with liquid red dye to evaluate microleakage. As tube bar sealing agents three different materials were used (AGC Cem (AGC, resin based), Cervitec Plus (CP; varnish) and Gapseal (GS; silicone based). Four groups with eight specimens each were tested (GS, GS+AGC, AGC, CP). For cyclic loading, the attachment system was assembled parallel to the female counterparts in a chewing simulator. The mean retention forces of the initial and final ten cycles were statistically evaluated (ANOVA, α≤.05).


RESULTS
All groups showed a significant loss of retention forces. Their means differed between 30-39 N initially and 22-28 N after 50,000 loading cycles. No significant statistical differences could be found between the groups at the beginning (P=.224), at the end (P=.257) or between the loss of retention forces (P=.288). Microleakage occurred initially only in some groups but after 10,000 loading cycles all groups exhibited microleakage.


CONCLUSIONS
Long-term retention forces of the SFI-Bar remained above 20 N which can be considered clinically sufficient. The sealing agents in this study are not suitable to prevent microleakage.
Dental Material Sciences, Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts University at Kiel, Kiel, Germany.
Christian Johannes
CJ
Mehl
Dental Material Sciences, Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts University at Kiel, Kiel, Germany.
Martin
M
Steiner
Dental Material Sciences, Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts University at Kiel, Kiel, Germany.
Klaus
K
Ludwig
Dental Material Sciences, Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts University at Kiel, Kiel, Germany.
Matthias
M
Kern
Chewing simulator; Cyclic long-term loading; Implant; Microleakage; Retention; SFI-Bar