From facial surface acquisition to digital orthopedic support

Biomechanical rationale, clinical proof-of-concept, and validation agenda for a patient-specific Digital Sky Hook

Abstract

Objective: To document the clinical-technical proof-of-concept of a patient-specific Digital Sky Hook for maxillary protraction, emphasizing how non-contact facial acquisition and additive manufacturing may stabilize the extraoral support interface for classical chin-supported mechanics.

Methods: Two clinical-technical applications were considered. The index case, a growing female patient with skeletal Class III malocclusion and maxillary deficiency, was described in detail because complete acquisition, design, fabrication, delivery, seating assessment, and follow-up documentation were available. A second ongoing-use application documented procedural repeatability without statistical or comparative outcome claims.

Results: Three design and printing iterations were required before standardizing the index appliance. The finalized framework showed passive seating, required no hydrocolloid foam or compensatory lining, and was used for 12 to 14 hours per day over an 8-month period without clinically relevant soft-tissue adverse events. Exploratory comparison with a conventional support showed border discrepancies of approximately 2.0 mm superiorly and 2.5 mm inferiorly. The workflow was reproduced in a second patient who received the appliance and remained in active use.

Conclusion: This Methods / Technical Note / Validation Study establishes the feasibility and procedural repeatability of a scan-derived, patient-specific chin-support interface for a classical Sky Hook-type maxillary protraction system. The workflow reduced dependence on facial molding, enabled passive seating without compensatory lining in the index case, and provides a traceable platform for metrological, mechanical, pressure-distribution, and prospective clinical validation