Abstract
Apical lesions have been considered to be caused by the bacteria in the root canal. However, many reports have insisted that no bacteria were found in apical lesions. Furthermore, the relationship between these bacteria and inflammatory cells in the lesions remains still unknown.
For this reason the author prepared 99 apical lesion cases and observed for the presence or absence of bacteria with various stainings light-microscopically. They were observed in 56 cases (56.6%) of the lesions consisting of 60 colonies of gram-positive and 13 of gram-negative bacteria. Several kinds of cocci were found most frequently followed by mycetes, small and large rods. These bacteria were often observed in the part of fibrous tissues with relatively little infiltrating cells such as lymphocytes or plasma cells.
Immunohistochemical staining revealed the helper/suppressor T cell ratio was higher in the bacteria positive lesions. In all cases, B cells were observed as much as T cells, and the average of T/B cell ratio was 1.93.
No correlation was recognized between the clinical state and the existence of bacteria.
