Effect of Inflammatory cell infiltrate on Epithelial Thickness in Oral and Pathological Odontogenic Epithelia

Objectives: This study investigated changes in thickness of buccal epithelium, the epithelium of dentigerous cysts and the epithelium of keratocystic odontogenic tumours in relation to varying degrees of infiltration by inflammatory cells.
Methods: Histological preparations of biopsies of the buccal mucosa from 22 volunteers were compared with those from 23 dentigerous cysts and 18 odontogenic keratocysts for inflammatory cell infiltrate and epithelial thickness.
Results: Samples from the buccal mucosa presenting with low inflammatory cell infiltrate had a mean epithelial thickness of 324.6 ± 13.7 µm, and this reduced only slightly to 302.4 ± 16.8 µm in those from tissues with severe inflammatory cell infiltrate. On the contrary, epithelia in dentigerous cysts showed an increase in thickness from a mean of 64.6 ± 8.2 µm to 178.2 ± 11.3 µm in tissues presenting with low and severe inflammatory cell infiltrate respectively. Likewise, epithelial thickness in keratocystic odontogenic tumours showed an increase from a mean of 69.3 ± 9.9 µm to a mean of 148.3 ± 11.3 µm in tissues presenting with low and severe inflammatory cell infiltrate respectively. In both cases, the change in epithelial thickness correlated with the degree of inflammatory cell infiltrate.
Conclusions: Increase in epithelial thickness of dentigerous cysts and keratocystic odontogenic tumours correlates with degree of inflammatory cell infiltrate and this could present challenges to histological diagnosis of these conditions.