| K-number | K251758 |
| Device name | Serafin® |
| Applicant | Tns Co., Ltd. |
| Product code | NXC |
| Device class | Class II |
| Decision date | Sep 11, 2025 |
| Decision | Substantially Equivalent |
| Regulation | 872.5470 |
Serafin® is a clear aligner system composed of a series of transparent, removable orthodontic appliances manufactured using thermoforming technology. It is customized based on a 3D digital model of the patient's teeth and a dental practitioner's prescription. The device applies continuous gentle force to realign teeth for treatment of dental malocclusion in patients with mixed and permanent dentition, with each aligner worn for at least 2 weeks and total treatment lasting 6 to 24 months.
Both Serafin® and its predicate (Invisalign) use series of transparent removable appliances manufactured via thermoforming of thermoplastic polyurethane polymers onto 3D-printed models derived from digital scans. Both employ proprietary 3D software to create customized treatment plans reviewed by the dental practitioner. Serafin® uses Zendura FLX material (3-layer thermoplastic urethane/copolyester) versus Invisalign's SmartTrack™, but both are biocompatible thermoplastic polymers intended for clear aligner use. Both devices lack a mandibular advancement feature (MAF), which is not needed for the subject device's intended use.
ISO 20795-2 (orthodontic base polymers); ISO 10993-1, ISO 10993-5, ISO 10993-10, ISO 10993-11, ISO 10993-17, ISO 10993-18, ISO 10993-23 (biological evaluation); ISO 7405 (biocompatibility in dentistry); ADA ANSI 41-2020; MFDS guideline on orthodontic resin appliances.
Serafin® and Invisalign share identical principles of operation, indications for use, clinical conditions, patient populations, and manufacturing processes. Both apply gentle continuous force via transparent removable appliances manufactured from thermoforming thermoplastic polymers with biocompatible polyurethane copolymers. Although materials differ slightly (Zendura FLX vs. SmartTrack™), both meet relevant physical and chemical performance standards for water sorption, solubility, and flexural strength, demonstrating chemical, biological, and functional equivalence. Biocompatibility and toxicological risk assessments confirm Serafin® meets safety requirements comparable to the predicate.
View the full FDA submission: accessdata.fda.gov