The Role of Distinct T Cell Subsets in Periodontitis—Studies from Humans and Rodent Models

Periodontal disease results from an interaction between the host’s defense mechanisms and the microorganisms that constitute the dental plaque biofilm, and penetrate gingival tissue. Therefore, the progression and severity of the disease are strongly modulated by the host immune response, particularly, T cell responses. Because T cells consist of a variety of subpopulations, numerous studies have attempted to associate an impaired balance between each T cell subset and periodontal tissue destruction in periodontitis patients. Here, we overview studies examining human specimens obtained from patients with periodontitis and experiments analyzing rodent models with age-related or pathogen-induced experimental periodontitis. Human research provides valuable insights but also inconsistent results, which may be attributed to the difference in experimental approaches and lack of evaluation of disease activity. Rodent models have shown that an optimal balance between functionally different T cells is essential in the protection against periodontal tissue destruction.