Introduction: Porphyromonas gingivalis (Pg) levels progressively increase in quantity and quality in the course of orthodontic treatment posing a risk to periodontal health.

Objective: To analyze the existing literature on the prevalence, clinical manifestations, diagnostic methods, treatment and prevention of Porphyromonas gingivalis from a systemic, oral and orthodontic point of view.

Methodology: A literature review was carried out by searching databases using the keywords: "Porphyromonas gingivalis", "prevalence", "orthodontics", "treatment", "prevention", "diagnosis", "levels", "systemic", "treatment" and "periodontitis".

Results: There is a 68.2% prevalence of Pg in periodontal pockets which increases during orthodontic treatment. Its main clinical manifestations in orthodontic treatment are increased depth and bleeding on probing, decreased level of clinical attachment and increased gingival and periodontal index. Pg is detected by measuring salivary MMP-9 levels by ELISA and intraoral clinical examination. Treatment for Pg infection includes mechanical therapy and adjuvant therapies such as the use of amoxicillin and metronidazole, chitosan and azithromycin or azithromycin alone. Toothbrushing and interproximal cleaning are the cornerstones of preventing the occurrence of Pg during orthodontic treatment, in conjunction with oral and periodontal hygiene education.

Conclusion: Pg levels increase during orthodontic treatment, which implies a risk for the development of periodontitis during and after treatment, its prevention is important at all stages of treatment.