MORPHO-BIOCHEMICAL RISK FACTORS OF MANDIBULAR MOLAR ERUPTION

In modern dentistry, the issue of impaired eruption of mandibular molars is becoming increasingly relevant, as its pathogenetic mechanisms remain insufficiently explored. The nitric oxide system, particularly the activity of inducible nitric oxide synthase (iNOS) and arginase (ARG), which perform opposing functions in inflammation, tissue remodeling, and osteogenesis, may play a significant role in these processes. The aim of this study was to assess the activity levels of iNOS and ARG in the gingival mucosa above retained mandibular molars and to analyze the morphological characteristics of these tissues. The study was conducted on gingival biopsies from 83 patients aged 12 to 24 years, divided into three groups: with complete retention, partial retention, and without retention (control). Biochemical parameters were measured in 10% mucosal homogenates, while histological analysis was performed using light microscopy. In patients with partial retention, iNOS activity increased by 111.49%, and in complete retention by 98.85%, compared to the control group. Meanwhile, ARG activity decreased by 21.32% and 32.35%, respectively. These results indicate a significant rise in the iNOS/ARG index in the retention groups, suggesting a predominance of M1-type inflammatory macrophage polarization. Histologically, the control group showed a normal stratified keratinized epithelium and uniform connective tissue structure. In partial retention, mucosal edema, vascular dilation, and increased numbers of macrophages and lymphocytes were observed. In complete retention, epithelial thickening, dilated capillaries with signs of stasis, and massive cellular infiltration were detected. These findings suggest that iNOS activation and ARG suppression in the gingiva over retained molars are biochemical markers of inflammation and tissue alteration, contributing to the disruption of physiological tooth eruption. Further research should focus on identifying potential therapeutic targets to modulate the local inflammatory microenvironment and support normal tooth eruption.