Dorsal Fin Appliance

The Dorsal Fin appliance uses interlocking acrylic fins — rather than metal connectors or elastic straps — to guide mandibular advancement. Its metal-free design makes it ideal for patients with metal allergies.

• Upper Tray — Acrylic with dorsal fin (wing-shaped projection) on each side • Lower Tray — Acrylic with receiving channel for the dorsal fin • Interlocking Fins — Acrylic wings that guide closure into protrusion • Optional Ball Clasps — For improved retention in partially edentulous cases

During closure, the acrylic dorsal fins on the upper tray slide into the receiving channels on the lower tray, guiding the mandible forward. The fin angle determines the advancement amount. Because it relies on soft-tissue retention rather than tooth-borne clasps, it works well for partially edentulous patients.

1. Receive intraoral scans and protrusive bite 2. 3D-print working models 3. Wax up upper and lower trays with dorsal fin mechanism 4. Carve fin angle to match prescribed advancement 5. Flask and process with heat-cured PMMA 6. Verify fin-channel interlock on articulator 7. QC: Fin angle verification, interlock smoothness, retention check

• Acrylic: Heat-cured PMMA (ISO 20795-1) • Fin angle: Prescribed per case, typically 45-60° • No metal components • Suitable for partially edentulous patients (minimum 8 teeth per arch) • QC: Fin-channel fit test, acrylic clarity, edge polish