Estudo dos efeitos da deficiência de testosterona sobre o periodonto e reabsorção radicular durante a movimentação dentária induzida em molares traumatizados: estudo experimental em ratos

Abstract

The success of tooth movement in traumatized teeth depends on the severity of the injury, and root resorption (RR) is an undesirable and possible consequence to occur before, during and after orthodontic treatment. In addition, the patient's hormonal status has a great impact on the professional's behavior since it can directly influence the success of orthodontic treatment. Testosterone (T) is the major male sex steroid hormone involved in the differentiation, sexual development and control of male reproductive functions. The decrease in T concentrations is associated with a decrease in alveolar bone mineral density, which can significantly increase the speed of tooth movement and its influence on bone and root resorption. Thus the objective of this study was to evaluate the effects of testosterone deficiency associated with dental trauma (DT) and its influence on bone and root resorption during induced tooth movement (ITM) in rats. For this, 48 male Wistar rats were used, separated into 08 experimental groups, with 06 animals in each: Group 1: control (CON); Group 2 (ORCH): composed of animals submitted to bilateral orchiectomy; Group 3 (DT): composed of animals that were submitted to dental trauma; Group 4 (ORCH + DT): composed of animals submitted to DT and bilateral orchiectomy; Group 5 (ITM) composed of animals that underwent induced tooth movement (MDI); Group 6 (ITM+ORCH): composed of animals that underwent ITM and bilateral orchiectomy; Group 7 (ITM+DT): composed of animals that underwent ITM and DT and Group 8 (ITM+ORCH+DT) composed of animals that underwent ITM, DT and bilateral orchiectomy. After the experimental period the animals were euthanized, weighed and the jaws were removed, fixed in 10% formaldehyde, decalcified, cut at 5 µm and stained with hematoxylin and eosin. Orchidectomy increased the rate of ITM in the G6 and G8 groups when compared to the G5 and G7 groups. Vascular changes in the periodontal ligament and dental resorptions were observed more frequently in the G8 animals in all regions evaluated. The drop in testosterone, associated with dental trauma, may negatively impact orthodontic treatment, causing periodontal changes and root resorption. No statistically significant differences were observed in the body weight of the animals at the end of the experimental period. Orchiectomy increased the rate of MDI in the G6 and G8 groups when compared to the groups to the other experimental groups, and the highest movement rate was verified in the G8 group. Histologically, the animals submitted to orthodontic movement had a decrease in the space of the periodontal ligament in the area of compression, increase of the space of the tension area, presence of inflammatory cells in the periodontal ligament and several osteoclasts around the alveolar bone, mainly in the intersegmental region –radicular. The number of reabsorption points in the distal root was higher in all groups, compared to the control group. However, the association of trauma, with orchidectomy and induced tooth movement, potentiated the observed effects. is concluded that the androgen deficit increases the rate of orthodontic movement and the association of factors (trauma, castration and tooth movement) induce a higher incidence of root resorption in the animals