Introduction: Fixed lingual retainers are commonly used to maintain teeth position after orthodontic treatment. While computer-aided design/computer-aided manufacturing (CAD/CAM) technology has been established in dentistry, its potential use in fixed retainer therapy has not been investigated. The aim of this in vitro study is to compare the mechanical properties of conventionally fixed lingual retainers to those virtually designed and machine-made using digital CAD/CAM technology.

Materials and methods: The study involved producing twenty, three-dimensional, identical printed wax models using the Varseo S 3D printer (BEGO, Bremen, Germany) with VarseoWax Model Material (BEGO, Bremen, Germany). Two groups were categorized, differing in the manufacturing process and material of the lingual retainer. The first group used CAD/CAM technology to produce the retainers, while the second group used conventional stainless-steel wires. The retainers were attached to the lingual surface of the lower front teeth and subjected for a mechanical fracture test using the Zwick/Roell Z010 universal testing machine (Zwick/Roell, Ulm, Germany). The dental arch was then loaded labially to evaluate the fracture strength of the lingual retainer.

Results: Statistical analysis was performed using Sigma Plot 13.0 (Systat, San Jose, USA), and no significant differences were found between the two groups (p>0.05).
Conclusion: This study found no significant difference in mechanical properties between the VarseoSmile Crown plus (BEGO, Bremen, Germany) material and conventional stainless-steel wire for lingual retainers.