Histological and immunohistochemical characteristic of the gingival stroma in the portion of the third molars in children of various age

Abstract

Aim: To evaluate the state of the gingival stromal elements in the portion of the third molars requiring extraction of these teeth due to orthodontic indications considering the stage of tooth germ formation. Materials and Methods: The surgery to extract third molars due to orthodontic indications was performed on 95 children aged 11 to 18 years. The three groups of observation were isolated according to clinical-radiological signs: І (n=30) – children aged 11-13 years; ІІ (n=35) – children aged 13-16 years, and ІІІ (n=30) – children aged 16-18 years. During surgery, the samples of gums were taken from the adjacent areas for examination. The samples were fixed, dehydrated, paraffinized for further histological processing. Immunohistochemical methods were used according to the protocols supplied by a producer. In particular, by means of immunohistochemical method, Ki-67, CD-34 antigens and vimentin with primary antibodies against them were determined. The primary antibodies were visualized by the polymeric visualization system with diaminobenzidine giving a brown color to the places of location of the antigens examined. The data obtained were statistically processed. Results: The results of the study showed that specific gravity of the vascular bed in the gingival papillary layer of children was the most variable. It ranges from (12,7±0,09) % at the stage of “D” root formation to (54,8±0,17) % at the “H” stage. Lower concentrations of CD-34 antigens and vimentin are found in the endotheliocytes of children aged 13-16 and 16-18 years, compared to the children aged 11-13 years (p<0,05). No changes were found in the specific volume of the blood vessels, CD-34 antigens and vimentin in the reticular gingival layer of children from the groups of observation. Conclusions: Therefore, the conducted histological and immunohistochemical study of the connective gingival tissues in the portion of the third molars in children enables to draw a conclusion that in the process of formation of the root of this tooth a number of changes occur in the gingival stroma. They include an increase of the blood flow volume in the papillary gingival layer on the background of a decreased concentration of CD-34 genes and vimentin, a longer stage of development of the third molar root. The specific volume of the islets of neoangiogenesis of the papillary gingival layer is the largest in children aged 13-16 years.