Abstract
Introduction: Prior in vitro work has shown that implants restored with aftermarket (AM) abutments are more prone to leakage at the implant-abutment interface (IAI) than implants seated with their original equipment manufacturer (OEM) abutments. The goal of the current study was to examine the relationship between bacterial colonisation at the IAI and implant parameters using OEM or AM abutments on identical implants. It was hypothesised that microbial colonisation at the IAI may increase peri-implant inflammatory cell accumulation and lead to increased bone and soft tissue loss around the AM abutments.
Method: Sixty ΓΈ4/3 mm x 10 mm implants were placed into healed mandibular post-extraction ridges in ten mature ewes. Abutments were placed immediately or at 2nd stage surgery after 2 months. Six groups (n=10) were evaluated as follows: Delayed aftermarket abutment (A), delayed OEM abutment (B), immediate aftermarket abutment (C and D), immediate OEM abutment (E and F). Radiographs and microbial sampling were taken at baseline, 2 months, and 4 months. Identification and relative quantification of DNA for oral microbial species was performed using Polymerisation Chain Reaction (PCR) (IAI Padotest, Switzerland). Mean percent bone- to-implant contact (%BIC) and distance to first bone contact were calculated from two images per implant using Image J software. Linear mixed models were used to look for between group differences and mixed logistic regression models used for the binary outcomes. Analyses were conducted using Stata 14.1 and p<0.05 was considered statistically significant.
Results: While there were more failures of the implants restored with aftermarket abutments (14 vs. 8) this difference failed to reach statistical significance (p=0.17). There was no statistical difference between OEM vs. aftermarket for %BIC, first bone contact, radiographic bone changes, height of soft tissue, bone density, or microbial colonisation. There was no correlation between microbial leakage and implant outcomes.
Conclusion: This animal study found no difference in microbial leakage between OEM and AM abutments. There was no apparent relationship between increased microbial leakage and implant outcomes. Statistical analysis was complicated by the higher-than-expected number of implant failures. While some intriguing trends were noticed, a larger human study is now recommended to further explore this relationship.