Preventive contamination with lactobacillus reuteri of the implant-abutment connection: An in vivo study

The aim of this study is to preventively contaminate the abutment-fixture connection (AFC) with Lactobacillus reuteri (L. reuteri), to evaluate the presence of micro leaks in different types of implant-abutment connections, by measuring the concentration of L. reuteri in the sulcular fluid over time. This microorganism produces the Reuterine, an antibiotic which counteracts the development of other microbial species. Fourteen biphasic implants were placed on 10 patients (3 women; 7 men; mean age 55.9±16.54y). Eight implants had a flat top connection (internal Hex) while six implants had a tapered connection (conical plus octagonal). At the time of prosthetic finalization, before the healing screw was removed, the sulcular fluid was harvested, on each implant, by means of three sterile paper cones placed into the gingival sulcus and left in place for 20sec before to be transferred to a sterile tube. Once the healing screw has been removed, first the implant connection has been gently dried with air jet for 10sec and then completely filled with L. reuteri DSM 17938 (Reuflor, Italchimici, Italy). Immediately after the prosthetic finalization the sulcular fluid was then harvested again, with the same procedure described before, and repeated at 1 week and 1 month of follow up. The samples were then sent for subsequent DNA extraction and real-time PCR. Our results demonstrate that the concentration of L. reuteri, in the sulcular fluid, does not persist over time in case of preventive contamination of the AFC, demonstrating no significative differences between flat top and tapered connections. Therefore, the use of the latter does not lead to a lower risk of Peri Implant Disease (PID). Long-term studies, involving a larger number of samples, are advisable to confirm these findings.