Durability and Stability of Coaxial Wire and 3D-Printed Lingual Bonded Retainer: A Finite Element Study

Abstract

Objective: To evaluate the durability and stability of Coaxial & 3D (Three-dimensional) -printed bonded lingual mandibular retainer wire (3-3) at the middle third position with the application of forces. The objective is to evaluate the displacement of teeth, stiffness, and stresses on the wire. Methods: A comparison of coaxial wire (six-stranded stainless-steel wire) with 3D-Printed retainer wire (chrome cobalt alloy) was done by conducting a FEM (Finite Element Method) study for which mesh models were prepared onto which forces were applied. A load of 10N was applied to simulate biting forces and protrusive jaw movements during mastication. Results: There was a uniform displacement of teeth in the 3D-printed retainer wire whereas, in the case of coaxial retainer wire more force was noted onto the central incisor due to its low stiffness and thus inability to transfer force to an adjacent unit. High stiffness, von mises, and shear stresses were found to be present in the case of a 3D-printed retainer for which the high modulus of elasticity is responsible. The factor of safety for both materials was high but when compared to each other it was higher in the case of the 3D-printed retainer. Conclusion: 3D-Printed retainer wire showed higher durability and stability when compared to coaxial wire retainer, but requires clinical studies for better appraisal.