Background Odontogenic sinusitis (OS) presents more satisfactory therapeutic effect after endoscopic surgery compared with chronic rhinosinusitis (CRS) of other origin. The aim of the present study was to investigate the clinical characteristics, morphological features, and epithelial barrier function of sinus mucosa of OS and discuss the possible relationship with good prognosis. Methods A total of 25 subjects with OS, 7 CRS without nasal polyps (CRSsNP), 10 CRS with nasal polyps (CRSwNP), and 9 control subjects were recruited. The biopsy specimens were stained with hematoxylin and eosin for general observation of cytomorphologic features. Epithelial tight junctions (TJs) protein claudin-4 expression was determined to evaluate the epithelial barrier integrity by using immunofluorescence and Image-Pro Plus software analysis. The representative cytokine profiles regarding T helper 1 (Th1) (interferon [IFN]-gamma), Th2 (interleukin [IL]-5), and Th17 (IL-17) were examined by reverse transcription-polymerase chain reaction (RT-PCR). Results Extensively small papillary protrusions could be seen in the maxillary sinus mucosa of OS patients under nasal endoscopy, similar to the morphological behavior, which also presented as papillary folds in the surface of the epithelium. The epithelium in OS kept an increased claudin-4 expression compared with that seen in CRSsNP, CRSwNP, and control subjects. The inflammatory pattern analysis demonstrated that OS belonged to the lymphocyte and plasma cell-dominant cellular phenotypes, whereas IL-17 was dominant compared with IFN-gamma as well as IL-5. Conclusion The odontogenic infections might induce the formation of papillary mucosa folds and enhance the epithelial TJ barrier function. OS exhibited as lymphocyte and plasma cell-dominant cellular phenotypes and Th17 cytokine profiles.