Influence of Different Torques on the Size of the Microgap and Bacterial Leakage in Three Commercial Implant Systems:...

To evaluate the adherence of three types of bacteria (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) and the size of the microgap of three different implant systems (JD Icon Plus [JD], ORA system [Ora; Dental Tech], and Ankylos [Dentsply Sirona]) under four different screw torque values.

A total of 10 samples for each tested implant system were used under different torques to determine the width of the gaps. The abutments were connected to the fixtures using a universal digital wrench, and an initial torque value of 10 Ncm was applied for all samples. After the assessment of the microgap, the fixture was repositioned into the bench vise, and the torque was increased to 20, 30, and 40 Ncm. The microgap assessment was done using a scanning electron microscope (SEM). Before the torque was increased to 40 Ncm, 11 samples for each tested implant system were used under 30 Ncm torque to determine the leakage in the tested implants for S. aureus, E. coli, and P. aeruginosa. Data were analyzed with multiple one-way ANOVA, Post hoc, and chi-square tests.

The Ankylos system showed the widest gap under all torques (P < .005), and the JD system demonstrated the lowest gap (P < .005). Regarding the bacterial leakage, JD showed the highest adherence to the bacteria, and the adherence was mainly to P. aeruginosa, while the Ankylos system showed the lowest adherence (P < .005).

Within limits, the higher torque provides a higher fit to the implant-abutment interface (IAI), offering more stability. Ankylos implants showed the widest gap, while JD showed the narrowest. Regarding the bacterial leakage, JD showed the highest adherence to P. aeruginosa, while the ORA system showed the highest adherence to E. coli.