Characteristics of the Gingival Epithelium of Children’s Third Molars at Different Stages of Root Formation

Abstract

Extraction of impacted and dystopic third molars is a rather traumatic manipulation accompanied by a large bone defect and wound infection. Therefore, it is advisable to perform hermectomy, which has a number of advantages over typical and atypical methods of tooth extraction. An important stage of any surgical intervention is the postoperative period, which is characterized by a certain duration and the presence of complications, which is due, among other things, to the regenerative potential of tissues, especially epithelial tissues. Aim of the study is to evaluate the condition of the gingival epithelium in the area of third molars in children who have to have these teeth extracted for orthodontic reasons, taking into account the stage of tooth formation, i. e. its root.Material and Methods. Third molar extraction for orthodontic indications was performed in 95 children aged 11 to 18 years.Clinical and radiologic examinations were performed in three groups: Group I (n=30) – children aged 11-13 years; Group II(n=35) – children aged 13-16 years, and Group III (n=30) – children aged 16-18 years. During surgery, gingival tissue was taken from the adjacent areas for examination. The material was fi xed, dehydrated, and paraffi n- embedded for histologic processing. Immunohistochemical techniques were performed according to the manufacturer’s protocols. Specifi cally, immunohistochemical detection of Ki-67 antigen was performed with primary antibodies against it. Digital copies of the images were analyzed using the specialized computer program ImageJ v1.52 (freeware, USA). The obtained digital data were statistically processed.The digital data obtained were statistically processed. A preliminary test for normality of the distribution was carried outusing the Shapiro- Wilks method. According to this criterion, the hypothesis of normality of the distribution was not rejectedfor all the statistical samples studied (at the signifi cance level of p=0.05), so we used mainly parametric methods of statistical analysis: calculation of the arithmetic mean and its error, unpaired two-sided Student’s t-test. However, because the statistical samples were small, the non-parametric Mann- Whitney test was used in addition to the Student’s t-test.The study was conducted as part of the complex research work of the Department of Pediatric Dentistry of the Bukovinian State Medical University on the topic «Development of methods of prevention and treatment of the main dental diseases in children, taking into account the risk factors of their development» (state registration number: 0121U110122). The conducted research complied with bioethical norms, as stated in the conclusions of the Bioethics Commission of the Bukovinian State Medical University (№ 1 dated 17.09.2020).Conclusions. Thus, the histological and immunohistochemical study of the gingiva in the area of the third molar allows usto conclude that during the formation of the root of this tooth, a number of changes occur in the epithelial cover of the gingiva, namely: an increase in the number of epithelial layers with a decrease in their proliferative activity. The obtained data indicate a decrease in the regenerative potential of the multilayered squamous epithelium with increasing age of the child and the degree of third molar formation, which is refl ected in the clinical picture of the course of surgical intervention.