eng Science and Education Publishing American Journal of Medical and Biological Research 2328-4099 2026-05-05 14 1 8 14 10.12691/ajmbr-14-1-2 AJMBR20261412 article Mikou S. mikousalwa12@gmail.com 1 Boudraa I. 1 Boubdir S. 1 Chelhaoui N. 1 Chemlali S. 1 Khlil N. 1 Kissa J. 1 Department of Periodontics, University of Hassan II of Casablanca, Casablanca, Morocco Introduction: Periodontitis is a complex multifactorial disease resulting from a dysbiosis of the oral microbiota. Familial aggregation of this condition has been demonstrated, making intrafamilial transmission of periodontopathogenic bacteria possible, particularly Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Materials and Methods: A systematic literature search was conducted using three electronic databases (MEDLINE [PubMed], Scopus, and Google Scholar). The search included human studies published in English between January 2012 and September 2025 that investigated the intrafamilial transmission of periodontal pathogens, specifically Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. The preparation of this literature review followed the guidelines of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Results: Ten studies were included in this systematic review, comprising four observational studies, four case¨Ccontrol studies, one pilot study, and one case report. These studies suggest the existence of both horizontal and vertical transmission of periodontal pathogens (A. actinomycetemcomitans and P. gingivalis). Conclusion: Intra-familial transmission of periodontal pathogens has been discussed mainly in studies focusing on vertical transmission. To better address these issues, larger-scale studies are required. The mere presence of periodontopathogenic bacteria does not appear to be sufficient to trigger periodontal disease. Many questions remain unanswered regarding the exact relationship between this transmission and the development of periodontitis. https://pubs.sciepub.com/ajmbr/14/1/2/ajmbr-14-1-2.pdf periodontitis intrafamilial transmission Aggregatibacter actinomycetemcomitans Porphyromonas gingivalis familial aggregation vertical transmission horizontal transmission JP2 clone systematic review