Abstract
Background: Periapical lesions are induced in response to injuries to periapical tissues, which are generally the result of infections within
the root canal. Mast cells actively participate to the inflammatory infiltration of periapical granulomas and cysts.
Objectives: The aim of this study was to detect and compare the presence of mast cells in inflammatory periapical lesions, including cysts
and granulomas.
Materials and Methods: In this cross-sectional study, 26 samples of inflammatory periapical lesions (17 cysts and nine granulomas) were
stained with an immunohistochemical technique using CD117 (C-KIT) antibody to detect mast cells. Then, mast cell count (the number of
mast cells in 0.2 mm2) and the intensity of mast cell staining were determined by two board certified pathologists. Fisher exact test and
t-test were used for statistical analysis, with P < 0.05 for statistical significance.
Results: Although mast cells were observed in all samples, there were more numerous in periapical granulomas compared to periapical
cysts, with no statistically significant difference (P = 0.076). The results also demonstrated that the staining in periapical cysts and
granulomas were of strong and moderate intensity, respectively, without any significant difference (P = 0.411).
Conclusions: According to the results of this study, it appears that mast cells are present in all the investigated inflammatory periapical
lesions and might play a role in the pathogenesis of these lesions.