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An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
Examination of the implant-abutment interface after fatigue testing
R M Cibirka1, S K Nelson, B R Lang
1School of Dentistry, Medical College of Georgia, Augusta, Ga 30912, USA. Rcibirka@mail.mcg.edu
The Journal of Prosthetic Dentistry
|March 27, 2001
Summary
Altering implant-abutment connection dimensions or eliminating the external hexagon did not significantly impact abutment screw stability after extensive fatigue testing. This suggests robust performance across different implant connection designs.
Area of Science:
- Biomaterials Science
- Dental Implantology
- Mechanical Engineering
Background:
- Dental implant stability relies on secure abutment screw fixation.
- Understanding how variations in implant-abutment interface geometry affect screw loosening is crucial for long-term clinical success.
- Previous research has not extensively evaluated the impact of modified or eliminated external hexagonal features on screw detorque values under dynamic loading.
Purpose of the Study:
- To investigate the effect of altered external hexagon dimensions and elimination of the external hexagon on the detorque values of abutment screws.
- To assess screw stability after subjecting dental implant-abutment specimens to prolonged fatigue testing.
Main Methods:
- Three groups of NobelBiocare implants (standard hexagon, modified hexagon, circular platform) were tested (N=10 per group).
- Procera abutments were attached using abutment screws tightened to 32 N/cm.
- Specimens underwent 5,000,000 cycles of dynamic loading (20-200 N) in a fatigue testing device.
- Abutment screw detorque values were recorded, and implant-abutment interfaces were examined macroscopically, radiographically, and microscopically.
Main Results:
- No instances of abutment looseness or longitudinal displacement were observed at the implant-abutment interface.
- Radiographic analysis revealed no screw bending or displacement.
- Mean detorque values were 14.40 ± 1.84 N/cm (standard), 14.70 ± 1.89 N/cm (modified), and 16.40 ± 2.17 N/cm (circular).
- A statistically significant difference was found only between the standard and circular designs (P=.031).
Conclusions:
- Modifying the fit tolerance or eliminating the external hexagon of the implant connection did not significantly affect abutment screw detorque values after 5 million fatigue cycles.
- The findings suggest that variations in the external hexagonal geometry have minimal impact on the long-term stability of abutment screws.
- This implies that different implant connection designs evaluated may offer comparable screw retention under simulated masticatory loads.
