Cross-Contamination in Dental Implant Impression Copings

To assess the potential risk of bacterial cross-contamination during analog impression-making for dental implants after disinfection using a conventional spray technique.

Eight patients, of varying ages and both genders, who had undergone dental implant treatment with a total of nine implants were enrolled in this study. Approximately 3 to 4 months after implant placement, clinical and radiographic examinations were conducted, and probing depths and bleeding on probing were recorded. Additionally, salivary flow evaluations were performed. Analog open-tray impressions were made using polyvinyl siloxane material. Once set, each implant impression coping was removed from the implant, and the impression was taken out of the patient's mouth. The retrieved impression was disinfected on all surfaces, with special attention given to the intaglio surface, impression coping, and screw area, using sodium hypochlorite. After a 10-minute disinfection period, the impression copings were swabbed with sterile paper points and placed into vials of liquid Columbia Broth for bacterial culturing. A new, unused implant impression coping was swabbed as a negative control, and a non-adjacent, non-implant site was swabbed as a positive control. Following incubation at 37°C for 24 hours, DNA was extracted from the samples that exhibited bacterial growth, and 16S DNA sequencing was performed.

Out of the nine samples, six showed bacterial growth, with Streptococcus being the most frequently identified genus. Implant sites that exhibited bleeding on probing were also associated with a higher presence of Rothia bacteria. There was also a higher presence of Neisseria bacteria in the group with higher salivary production. No bacterial growth was observed in the positive and negative control samples. No significant differences were found in the samples based on gender, age, or salivary flow.

Conventional implant impression-making using standard disinfection protocols and guidelines may lead to microbial contamination. Further research is warranted to investigate cross-contamination and disinfection techniques related to dental implant impression materials.