Biconometric Connections in Dental Implants: A Pilot Mechanical Study

TL;DR

This study examines biconometric dental implants to assess if micro-gaps form at connections under chewing forces, finding no significant gaps that could lead to implant failure.

Contribution

The study introduces a novel mechanical analysis of biconometric dental implant connections using micro-CT to detect micro-gaps under simulated chewing forces.

Findings

Micro-CT analysis found no micro-gaps greater than 10 µm in cap–abutment and abutment–fixture connections.

Mechanical loading and unloading did not induce micro-gaps in the fixture–abutment connection.

Results were consistent across all samples and experimental conditions.

Abstract

Background: In dental implants, micro-gaps at the fixation–abutment interface can cause peri-implantitis and/or loosening or loss of the fixation screw; therefore, three-dimensional imaging is widely used to examine different types of connections. In the present study, we focus on the analysis on biconometric connections to detect and (possibly) measure the presence of micro-gaps in the as-positioned state and after repeated loading and unloading. Methods: Seven biconometric dental implants were characterized using micro-computed tomography (micro-CT). In two specimens (group 1), the cap was inserted, and only the apical portion was imaged, to evaluate the cap–abutment connection; in the remaining five specimens (group 2), the fixture–abutment connection was analyzed. Two implants in group 2 were also subjected to load tests to verify whether stresses could induce the formation of micro-gaps as a consequence of preload loss. Results: Micro-CT analysis showed the absence of micro-gaps greater than 10 µm in both cap–abutment and abutment–fixture connections. This was verified, in the fixture–abutment connection, even after mechanical loading and unloading. The results were reproducible in all the investigated samples in the different experimental conditions. Conclusions: In the human force range during chewing, the conical connection showed a high level of resistance to micro-gap formation at the implant–abutment interface. The absence of micro-gaps, as demonstrated here, provides encouraging preliminary data regarding the stability of the biconometric connections, which will be further verified in follow-up studies on a larger sample size.

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