Comparison of bacterial colonization of implant abutment internal recess in internal hex and conical connection implants: An in vivo prospective study.

Aim: Microbial assessment of internal recess of two different internal implant connections in an in vivo study.

Study settings and design: This randomized, in vivo study included 40 patients requiring mandibular single-tooth implant-supported prostheses, allocated into two equal groups based on implant connection design.

Materials and methods: Group Internal Hex (IH) and group Conical Connection (CC) received implants with IH and CC, respectively. On the day of prosthetic loading, peri-implant sulcular fluid (PISF) sample was collected and stored. PISF samples were recollected after 3 months. Subsequently, the screw access hole was exposed, and the abutment screw was removed. Implant-abutment recess was washed with saline, lavage was sent for microbiological assay. The abutment screw and crown were restored. PISF was analyzed for interleukin-6 (IL-6).

Statistical analysis used: For nonparametric values Chi square test and for parametric values t-test was used to analyse the data.

Results: No implant failure or patient fallout was observed. In Group IH, 17 out of 20 samples were positive for aerobic viz-a-viz 7 samples from Group CC; P = 0.001. For anaerobic bacteria, similar results were obtained with a number of positive samples 19 as compared to 6 in respective groups; P = 0.00002. IL-6 values did not differ significantly from baseline to 3 months in either group.

Conclusion: Within the limitations of the study, results show higher bacterial contamination of implant recess in IH than CC. However, the bacterial load had an insignificant contribution to IL-6 levels in PISF of the patients of either group in this time period.