The periodontal ligament plays a vital role in orthodontic movement and force transfer. Tenascin and fibronectin may mediate the biological response to mechanical stress applied to teeth during orthodontic treatment.
This hypothesis was investigated immunohistochemically on twenty mandibular premolars of patients with orthodontics in Javeriana’s University. The right premolars were tipped vestibularly for a period of time ranging from 1 day, 21 to 40 days. The left premolars were a control group. Horizontal histological sections 3 microns thick, collected on adhesive tape while still frozen, then freeze-dried, were stained by an immunoglobulin-enzyme bridge method using rabbit anti-fibronectin polyclonal antibodies and anti-tenascin monoclonal antibodies. Immunoreactivity was detected in the periodontal ligament (PDL) of unstressed premolars. Positive staining for appeared to increase markedly after application of an orthodontic force in the compression and tension side for the tenascin and in the compression side for the fibronectin. These results demonstrate that mechanical forces alter extracellular matrix (tenascin and fibronectin), and that some responses are uniquely associated with either tension or compression. It is likely that these responses are important during remodeling of the periodontal ligament during orthodontic tooth movement.
Key words: fibronectin, tenascin, orthodontic movement, periodontal ligament.
