J Adv Prosthodont.  2016 Dec;8(6):465-471. 10.4047/jap.2016.8.6.465.

Evaluation of stability of interface between CCM (Co-Cr-Mo) UCLA abutment and external hex implant

• Yoon KJ
• Park YB
• Choi H
• Cho Y
• Lee JH
• Lee KW

• KMID: 2382592
• DOI: http://doi.org/10.4047/jap.2016.8.6.465

Abstract

PURPOSE
The purpose of this study is to evaluate the stability of interface between Co-Cr-Mo (CCM) UCLA abutment and external hex implant.
MATERIALS AND METHODS
Sixteen external hex implant fixtures were assigned to two groups (CCM and Gold group) and were embedded in molds using clear acrylic resin. Screw-retained prostheses were constructed using CCM UCLA abutment and Gold UCLA abutment. The external implant fixture and screw-retained prostheses were connected using abutment screws. After the abutments were tightened to 30 Ncm torque, 5 kg thermocyclic functional loading was applied by chewing simulator. A target of 1.0 × 10⁶ cycles was applied. After cyclic loading, removal torque values were recorded using a driving torque tester, and the interface between implant fixture and abutment was evaluated by scanning electronic microscope (SEM). The means and standard deviations (SD) between the CCM and Gold groups were analyzed with independent t-test at the significance level of 0.05.
RESULTS
Fractures of crowns, abutments, abutment screws, and fixtures and loosening of abutment screws were not observed after thermocyclic loading. There were no statistically significant differences at the recorded removal torque values between CCM and Gold groups (P>.05). SEM analysis revealed that remarkable wear patterns were observed at the abutment interface only for Gold UCLA abutments. Those patterns were not observed for other specimens.
CONCLUSION
Within the limit of this study, CCM UCLA abutment has no statistically significant difference in the stability of interface with external hex implant, compared with Gold UCLA abutment.

Keyword

CCM UCLA abutment; Chewing simulator; External hex implant; Removal torque value

MeSH Terms

Crowns
Fungi
Mastication
Prostheses and Implants
Torque

Figure

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  Fig. 1 Chewing simulator CS4 (SD Mechatronic, Feldkirchen, Westerham, Germany).

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  Fig. 2 A schematic diagram of connecting implant and prosthesis & loading position that is 3 mm away from the crown center.

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  Fig. 3 Typical graph of changes in the removal torque values with respect to elapsed time, which were measured every 0.1 sec by a driving torque tester.

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  Fig. 4 Means and standard deviations of removal torque value of the CCM and Gold UCLA abutment groups.

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  Fig. 5 Representative SEM photograph at interface of abutment in the CCM group (original magnification: ×50).

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  Fig. 6 Representative SEM photograph at the interface of abutment in the Gold group (arrows : remarkable wear patterns, original magnification: ×50)

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  Fig. 7 Representative SEM photograph at the interface of fixture in the CCM group (original magnification : ×50).

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  Fig. 8 Representative SEM photograph at the interface of fixture in the Gold group (original magnification : ×50).

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