In vitro assessment of internal implant-abutment connections with different cone angles under static loading using...

Area of Science:

• Biomaterials Science
• Dental Implantology
• Biomechanics

Background:

• Implant-abutment connection stability is vital for minimizing mechanical and biological complications in dental implants.
• Assessing microgap behavior and abutment displacement is crucial for understanding implant system performance.

Purpose of the Study:

• To evaluate microgap behavior and abutment displacement in different implant-abutment connection designs under static loading conditions.
• To compare the stability of conical friction-fit connections with angulated connections.

Main Methods:

• Four implant systems were tested: three with conical friction-fit connections (<12° cone angle) and one with an angulated connection (<40°).
• Static loading conditions ranged from 30 N to 200 N at 30° and 90° angles.
• Synchrotron-based microtomography and phase-contrast radioscopy with numerical forward simulation were used to measure microgaps and abutment displacement with 0.1 μm accuracy.

Main Results:

• Initial microgaps ranged from 0.15 to 9 μm across all tested implant systems.
• Microgap values increased with mounting force and angle, reaching up to 40.5 μm under 100 N off-axis loading at a 90° angle.
• Conical friction-fit connections (<12° cone angle) exhibited abutment displacement leading to outer implant wall deformation.

Conclusions:

• Conical implant-abutment connections with small cone angles (<12°) showed significant abutment displacement and outer wall deformation, unlike those with larger cone angles (45°).
• The design of the implant-abutment connection critically influences force distribution along the implant wall.
• Proper force distribution is likely essential for maintaining peri-implant bone stability.