Introduction: The microbial environment surrounding implant-supported overdentures plays a crucial role in the long-term success of rehabilitation, as inadequate disinfection can favor the growth of pathogenic species that jeopardize peri-implant health. The aim of this study is to analyze the effectiveness of a disinfection protocol for complete dentures anchored to ball attachments with respect to the peri-implant health of osseointegrated implants.

Methods: Thirty patients were randomly divided into two groups. All thirty patients had compatible flora (absence of spirochetes/Treponema denticola) at phase-contrast microscopy sampling. This was due to the modified oral hygiene protocol (sonic toothbrush and oral irrigator twice daily). The use of the irrigator was discontinued for all thirty patients. Group A disinfected their dentures with EC Ster daily, while Group B did not use EC Ster.

Peri-implant flora was re-examined with phase-contrast microscopy every month for 6 months.

Results: Patients in Group A maintained compatible flora at all samplings, but patients in group B did not (at 1 month, 2/15 patients developed incompatible flora, at 2 months 5/15, at 3 months 8/15, at 4 months 10/15, at 5 months 15/15, and at 6 months 15/15). Peri-implant parameters were stable and constant in group A, but they slowly worsened in group B (plaque index, bleeding on probing, peri-implant probing).

Conclusions: EC Ster maintains an environment unfavorable to the development of spirochetes (Treponema denticola), promoting greater stability in the peri-implant compartment.