The Utility of GFRP Orthodontic Wire for Clinical Application

Objectives: The glass fiber-reinforced plastic (GFRP) orthodontic wires made from polycarbonate and glass fiber. The purpose of this study was to investigate the utility of GFRP wire for clinical application, the typodont model simulation, and tooth movement in vivo.
Methods: GFRP round wire with a diameter of 0.45 mm (0.018 inch.) was prepared using 7µm glass fibers. As a control, nickel-titanium (Ni-Ti 0.018 inch) wire were also evaluated. The typodont model was simulated with a Class I malocclusion and mild crowding. We examined the differences in the maxillary and mandibular the inclination of the anterior teeth using by superimposition of 3D virtual models before and after treatment, and the strain force. Next, the maxillary second and third premolars were moved buccally by 5 weeks of five dogs, and the amount of tooth movement was measured. The expression levels of the TRAP protein in the alveolar bone (AB) was determined using an immunohistochemical analysis.
Results: The inclination toward the labial aspect and the major axis of the upper and lower incisors increased, respectively, after the experiment. No significant differences before and after treatment were noted between the wires (p<0.05). On comparing the strain force of both wires after ligating the wire (4 weeks) in the strain test, the force of the GFRP wires was slightly lower than that of the Ni-Ti wires. The average distance of tooth movement for the second and third premolars was 0.6-0.7 mm with labial tipping with both the GFRP and Ni-Ti wires in vivo. The expression of TRAP on the compression side in the AB was significantly increased in either group at 5 weeks. No significant differences in any parameters before and after treatment were noted between the groups (p<0.05).
Conclusions: GFRP wire can be used in place of Ni-Ti wire at the initial leveling stage.