In Vivo Biological Evaluation of Orthodontically Moved Incisors after Replantation

Abstract

Background and Objectives: There is still considerable controversy regarding the possibility of submitting replanted teeth to orthodontic movement (OM). The purpose of the present study was to evaluate the tissue response after orthodontic movement on replanted teeth. Materials and Methods: Sixty Wistar rats were randomly assigned to four groups (n = 15): G1, replantation without OM after 30 days; G2, replantation with OM after 30 days; G3, replantation without OM after 60 days, and G4, replantation with OM after 60 days. The maxillary left central incisors were extracted and the teeth were stored in milk media. After 30 min, the teeth were replanted and fixed with non-rigid immobilization. All specimens were observed after 30 and 60 days of replantation and then subdivided into two subgroups (with OM or without OM). The animals were euthanized after seven days of the OM started, and the maxillary bone blocks were processed for histological evaluation. Results: The histological results showed periodontal ligament repair in both periods studied without OM; however, ankylosis and root resorption was seen in all orthodontically moved teeth. Conclusions: The orthodontic movement did not favor tissue response in all replanted teeth, regardless of the experimental periods.

Keywords: avulsed tooth; in vivo; orthodontic movement; rats; replanted tooth.

Figure 1

Orthodontic appliance performed with 0.016” cross-sectioned round stainless wire in order to promote inclined dental movement and a diastema between both upper incisors.

Figure 2

The six root areas evaluated the cross-sectioned incisor root. A grid mask was superimposed to the geometric center of pulp cavity to evaluate the biological response of the periodontium according to the experimental period.

Figure 3

Photomicrographic of the repaired area of the periodontal ligament. Arrows indicate inactive resorption lacunae with neoformation of cement; C-cement; D-dentin; PL-periodontal ligament. Magnification: 40X; Stain: HE. HE: Hematoxilin and Eosin.

Figure 4

Photomicrographs of tooth presenting root resorption. (A) Inflammatory infiltrate in the periodontal ligament and inflammatory resorption with osteoblasts in the Howship’s lacunae. Arrows indicate active resorption lacunae (HE–40X). (B) Active osteoblasts in detail. Arrows indicate ruffled border (HE–100X). OC-osteoclasts; D-dentine; PL-periodontal ligament; BV-blood vessel.

Figure 5

Photomicrograph of tooth presenting ankylosis. (A) ample view of ankylosis (HE–40X). (B) replacement resorption in detail with bone tissue formation (HE–100X). AB-alveolar bone; D-dentine.