J Korean Acad Prosthodont.  2013 Oct;51(4):315-322. 10.4047/jkap.2013.51.4.315.

Effect of cyclic loading on axial displacement of abutment into implant with internal tapered connection: a pilot study

• Seol HW
• Heo SJ
• Koak JY
• Kim SK
• Han CH

• KMID: 2000156
• DOI: http://doi.org/10.4047/jkap.2013.51.4.315

Abstract

PURPOSE
To evaluate the axial displacement of implant-abutment assembly after cyclic loading in internal tapered connection system.
MATERIALS AND METHODS
External butt-joint connection implant and internal tapered connection implant were connected with three types of abutment for cement-retained prostheses, i.e. external type abutment (Ext group), internal tapered 1-piece abutment (Int-1 group), and internal tapered 2-piece abutment (Int-2 group). For each group, 7 implants and abutments were used. The implantabutments assemblies were clamped into the implant holder for vertical loads. A dynamic cyclic loading was applied for 150 +/- 10 N at a frequency of 4 Hz. The amount of axial displacement of the abutment into the implant was calculated at each cycle of 0, 5, 10, 50, 100, 1,000, 5,000, and 10,000. A repeated measures analysis of variance (ANOVA) for the overall effect of cyclic loading and the pattern analysis by linear mixed model were used for statistical analysis. Differences at P<.05 were considered statistically significant.
RESULTS
The mean axial displacement after 10,000 cycles were 0.714 +/- 0.488 microm in Ext group, 5.286 +/- 1.604 microm in Int-1 group, and 11.429 +/- 1.902 microm in Int-2 group. In the pattern analysis, Int-1 and Int-2 group showed continuous axial displacement at 10,000 cycles. There was no declining pattern of axial displacement in the Ext group.
CONCLUSION
The pattern of linear mixed model in Ext group showed no axial displacement. There were continuous axial displacements in abutment-implant assemblies in the Int-1 and Int-2 group at 10,000 cycles. More axial displacement was found in Int-2 group than in Int-1 group.

Keyword

Dental implant-abutment design; Internal tapered connection; Cyclic loading; Axial displacement; Settling effect

MeSH Terms

Dental Implant-Abutment Design
Pilot Projects*
Prostheses and Implants*

Figure

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  Fig. 1. Custom-made cyclic loading apparatus. A: Cyclic loading machine, ①: motor, ②: cam, ③: weight, ④: height adjusting screw ⑤: impact rod, ⑥: implant holder, B: Implant-abutment assembly was clamped into implant holder (collet and nut).

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  Fig. 2. This picture shows three groups of implant-abutment assemblies. A: Ext group (left): Straight abutment® was connected to Hexplant® implant, B: Int-1 group (center): 1-piece type Top abutment® (non-octagonal) was connected to Inplant® implant, C: Int-2 group (right): 2-piece type Top abutment® (octagonal) was connected to Inplant® implant.

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  Fig. 3. Digital torque gauge (MGT50) was used to tighten the abutment into implant at desired torque.

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  Fig. 4. Setting the applied load with a load cell. A: Height from metal cap to base of implant holder (h1) was measured for each implant-abutment assembly, B: The prop was adjusted for the load cell to be the same height (h1 = h2).

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  Fig. 5. Monitoring the applied load using strain analysis program (STT-200P).

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  Fig. 6. Electronic digital micrometer.

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  Fig 7. The patterns of axial displacement of each group with linear mixed models. A: fitted models of axial displacement in logarithmic scale, B: fitted models of axial displacement in original values.

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