Two Oral Protozoa Track Closely With Peri-Implant and Periodontal Disease

Oral protozoa such as Trichomonas tenax and Entamoeba gingivalis have long been observed in periodontal pockets, but their relationship to peri-implant disease has received far less attention. This cross-sectional study set out to evaluate the association between these two parasites and both periodontitis and peri-implantitis. The authors enrolled 140 participants across four groups of 35: patients with concurrent peri-implantitis and periodontitis, patients with peri-implant and periodontal health, patients with periodontitis alone (natural dentition), and periodontally healthy controls. Clinical periodontal and peri-implant parameters were recorded, and plaque samples were collected from around teeth (in the two tooth-only groups) and from around both teeth and implants (in the two mixed groups), then examined microscopically for the presence of the two protozoa.

Both T. tenax and E. gingivalis were detected significantly more often in tooth samples from the diseased groups (peri-implantitis+periodontitis and periodontitis-only) than in the healthy groups (p<0.001). Around implants, both parasites were also significantly more frequent in the diseased group than in the healthy group. Within the same mouth, detection rates on tooth and implant surfaces did not differ, suggesting a shared microbial ecosystem. Critically, the presence of both protozoa was independently associated with periodontitis presence, severity, and grading, even after accounting for other factors.

The authors are careful to frame this as an association rather than proof of causation: finding protozoa at diseased sites does not establish that they cause the disease. It may instead reflect opportunistic colonization of an already inflamed, biofilm-rich environment. Still, for clinicians the finding adds a piece to the puzzle of peri-implant and periodontal microbiology, alongside the more familiar bacterial pathogens. It also raises the practical possibility that oral protozoa could eventually serve as an additional biomarker of disease activity, or as a target if future research clarifies a causal role. For now, the take-home is descriptive: T. tenax and E. gingivalis track closely with periodontal and peri-implant inflammation, on both natural teeth and implants in the same patient.