Retention Forces between Titanium and Zirconia Components of Two-Part Implant Abutments with Different Techniques of Surface Modification.
BACKGROUND
The adhesive connection between titanium base and zirconia coping of two-part abutments may be responsible for the failure rate. A high mechanical stability between both components is essential for the long-term success.


OBJECTIVE
The aim of the present in-vitro study was to evaluate the influence of different surface modification techniques and resin-based luting agents on the retention forces between titanium and zirconia components in two-part implant abutments.


METHODS
A total of 120 abutments with a titanium base bonded to a zirconia coping were investigated. Two different resin-based luting agents (Panavia F 2.0 and RelyX Unicem) and six different surface modifications were used to fix these components, resulting in 12 test groups (n = 10). The surface of the test specimens was mechanically pretreated with aluminium oxide blasting in combination with application of two surface activating primers (Alloy Primer, Clearfil Ceramic Primer) or a tribological conditioning (Rocatec), respectively. All specimens underwent 10,000 thermal cycles between 5°C and 55°C in a moist environment. A pull-off test was then conducted to determine retention forces between the titanium and zirconia components, and statistical analysis was performed (two-way anova). Finally, fracture surfaces were analyzed by light and scanning electron microscopy.


RESULTS
No significant differences were found between Panavia F 2.0 and RelyX Unicem. However, the retention forces were significantly influenced by the surface modification technique used (p < 0.001). For both luting agents, the highest retention forces were found when adhesion surfaces of both the titanium bases and the zirconia copings were pretreated with aluminium oxide blasting, and with the application of Clearfil Ceramic Primer.


CONCLUSIONS
Surface modification techniques crucially influence the retention forces between titanium and zirconia components in two-part implant abutments. All adhesion surfaces should be pretreated by sandblasting. Moreover, a phosphate-based primer serves to enhance long-term retention of the components.
Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Hannover, Germany.
Nadine Freifrau
NF
von Maltzahn
Department of Prosthetic Dentistry and Biomaterials, Faculty of Medicine, Saarland University, Homburg, Germany.
Jan
J
Holstermann
Department of Prosthetic Dentistry and Biomaterials, Faculty of Medicine, Saarland University, Homburg, Germany.
Philipp
P
Kohorst
D000044:Dental Abutments; D003738:Dental Cements; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D066298:In Vitro Techniques; D008422:Materials Testing; D013499:Surface Properties; D014025:Titanium; D015040:Zirconium
D003738:Dental Cements; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
CAD/CAM technology; abutments; bonding; ceramics; surface properties; titanium; zirconia