Implant-Abutment Misfit after Cyclic Loading: An In Vitro Experimental Study.

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Implant Dentistry

Background:

• The implant-abutment interface is critical for dental implant success.
• Understanding factors affecting interface stability, like thermomechanical cycling (TMC) and abutment type, is essential.

Purpose of the Study:

• To evaluate the impact of TMC and abutment fabrication (overcast vs. completely cast) on misfit and compressive strength at the implant-abutment interface.

Main Methods:

• Forty external hexagon implants with angled abutments were divided into four groups: overcast with/without TMC, and completely cast with/without TMC.
• Specimens underwent 1 million cycles of loading (80 N, 2 Hz).
• Misfit was assessed via optical microscopy; compressive strength was tested using a universal testing machine.

Main Results:

• TMC significantly increased misfit in completely cast abutments compared to overcast abutments.
• Overcast abutments exhibited higher compressive strength than completely cast abutments, irrespective of TMC.
• Absence of TMC resulted in higher compressive strength for both abutment types.

Conclusions:

• Thermomechanical cycling exacerbates misfit, especially in completely cast abutments.
• Overcast abutments demonstrate superior mechanical integrity (compressive strength) compared to completely cast ones.
• TMC negatively affects both misfit and compressive strength of the implant-abutment interface.