Microbial leakage at the implant/abutment connection due to implant insertion maneuvers: cross-sectional study 5 years post loading in healthy patients

Abstract The aim of this study was to test if stress on the prosthetic connection during insertion maneuvers can induce micro-warping at the implant–connection. From Sept 2011 to July 20134, patients with implants loaded at least 5 years that were placed with two different insertion implant mounters – MP (conventional) and ME (mountless) – were selected from all those that had received dental implant therapy in the past and coming to routine check-up or spontaneous visits during the study period. Patients having implants loaded at least 5 years that were placed with two different insertion implant mounters – MP (conventional) and ME (mountless) – were recruited. Samples were obtained from inside the connection and the abutment surface (CIAS) using absorbent sterile paper tips. qRT-PCR was performed for total bacterial counts and loads of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Treponema denticola (Td), Prevotella intermedia (Pi), Peptostreptococcus micros (Pm), Fusobacterium nucleatum (Fn), Campylobacter rectus (Cr), Eikenella corrodens (Ec), and Candida albicans (Ca). The ANOVA test was used to test for differences. Nine patients (20 implants, MP group) and 5 patients (10 implants, ME group) were included. Regarding the red complex, Tf was seen in 80% and 30% of MP and ME implants respectively (p<0.001). Significant differences were also found in microbial load. For Td, proportions were 45% vs. 10% (p=0.022) with no significant differences at load levels. Regarding the orange complex, higher prevalence values were found in MP implants, although differences were non-significant. Microbial load levels for orange complex bacteria were higher for MP than ME, being these differences statistically significant for Fn (4.94 vs 3.09; p=0.001). Finally, Ec was only detected in the MP group, and Ca and Aa were not found in either group. Within its limitation (small sample size, retrospective analysis, indirect measurement method), the present study suggest that aA mounter not impacting on the prosthetic connection should be used to reduce microbial contamination of implants.