# Debonding characteristics of innovative 3D-printed lingual retainers following artificial aging and acid challenge

## TL;DR

This study evaluates the durability of 3D-printed lingual retainers after simulated aging and acid exposure, finding that semi-elliptical designs perform best.

## Contribution

The study introduces and evaluates innovative 3D-printed retainers with different cross-sectional designs for orthodontic use.

## Key findings

- 3D-printed semi-elliptical retainers showed the highest debonding forces.
- After acid challenge, semi-elliptical and oval retainers had no significant differences in debonding forces.
- 3D-printed retainers primarily exhibited cohesive fracture patterns.

## Abstract

Traditional fixed retainers used after orthodontic therapy have many downsides.

Innovative 3D-printed fixed retainers have been manufactured using nanoceramic hybrid resin-based material (SprintRay OnX®), investigating their durability to support long-term oral functions.

One hundred acrylic blocks with mounted premolar pairs were allocated into five groups, including three groups of 3D-printed retainers with 1-mm round cross-section, one group with 1.5-mm oval cross-section, and one group with 1.5-mm semi-elliptical cross-section, and conventional multistranded stainless steel G&H® retainers and Respond® retainers. The models with bonded retainers were exposed to artificial aging or acid challenge. The debonding forces and the subsequent failure patterns were investigated.

The 3D-printed semi-elliptical retainers exhibited the greatest debonding forces, while the 3D-printed oval, G&H®, 3D-printed round, and Respond® retainers decreased in descending order. After the acid challenge, no statistically significant differences were observed between the 3D-printed semi-elliptical and oval retainers. The 3D-printed retainers showed a prevailing cohesive fracture.

The debonding forces of 3D-printed semi-elliptical and oval retainers following simulated aging and acid exposure were encouraging. They might be a good candidate as lingual retainers.