Micro-leakage at the implant-abutment interface with different tightening torques in vitro

Objectives

This study evaluated the microleakage at the implant/abutment interface ofexternal hexagon (EH) implants and abutments with different amounts of bacteriaand tightening torques.

Material and Methods

A bacterial suspension was prepared to inoculate the implants. The first phase ofthis study used nine EH implants and abutments that were divided into three groupswith different amounts of bacterial suspension (n=3): V0.5: 0.5 µL; V1.0: 1.0 µL eV1.5: 1.5 µL, and tightened to the manufacturer''s recommended torque. The secondphase of this experiment used 27 assemblies that were similar to those used in thefirst phase. These samples were inoculated with 0.5 µL of bacterial suspension anddivided into three groups (n=9). T10: 10 Ncm; T20: 20 Ncm and T32: 32 Ncm. Thesamples were evaluated according to the turbidity of the broth every 24 hours for14 days, and the bacteria viability was tested after that period. The statisticalevaluation was conducted by Kruskal-Wallis testing (p<.05).

Results

During the first phase, groups V1.0 and V1.5 was presented with bacterialcontamination in all samples after 24 h. During the second phase, two samples fromgroup T10 and one from T20 presented positive results for bacterial contamination.Different amounts of bacterial solution led to overflow and contamination duringthe first 24 h of the experiment. The tightening torques did not statisticallyaffect the microleakage in the assemblies. However, the group that was tightenedto 32 Ncm torque did not show any bacterial contamination.

Conclusion

After 14 days of experimentation, the bacteria were proven to remain viable insidethe implant internal cavity.