Authors

(Years)

Country

Study

Sample size

Part tested

Technique used

Result

Conclusion

Friedrich L, et al. [5]

Austria

Exploratory pilot study

20 AD patients

Alveolar fluid to periodontal bacteria

RNA-based analysis

In 5 out 7 patients with periodontitis, a strain of P. gingivalis was found Association between the salivary presence of P. gingivalis and lower score in cognitive test was found.

Possible association between the most virulent strain of periodontitis, P. gingivalis, and the Alzheimer's disease.

Stephen SD, et al. [13]

USA

Prospective pilot study

10 AD patients

Matched saliva and CSF samples were taken and analyzed for P. gingivalis DNA

PCR

All 10 patients were positive to P. gingivalis.

Evidence for P. gingivalis infection in the brain of Alzheimer's disease patients is provided by CSF result.

James N, et al. [21]

USA

Longitudinal and case-cohort study

219 individuals (110 Alzheimer's disease cases and 109 controls without cognitive impairment)

Serum IgG antibody levels to periodontal bacteria: (P. gingivalis)

checkerboard immune-blotting

High antibody levels to P. gingivalis were found in 23% of subjects.

Serum IgG levels to periodontal bacterium are associated with an increasing risk for developing.

Pamela SS, et al. [20]

USA

Retrospective study and case-control study

158 subjects

IgG antibody levels to 7 oral bacteria were analyzed: (P. gingivalis)

ELISA

At baseline, similar levels of antibodies to P. gingivalis were found between patients with periodontitis and patients with Alzheimer's disease.

Oral bacteria associated with periodontitis induce high host responses in patients with Alzheimer's disease.

Noble JM, et al. [19]

USA

Cross sectional observational study

2355 participants

Serum P. gingivalis IgG

ELISA Three cognitive tests

Mean P. gingivalis IgG was higher among those with impaired performance for the 3 cognitive tests.

Patients with high levels of P. gingivalis IgG significantly tends more to impaired cognitive function.

Significant dose-response relation between increasing P. gingivalis IgG and subtraction test performance.