ETIOLOGY-SPECIFIC PROTECTIVE FACIAL HEADGEAR FOR THE PREVENTION OF COMBINED MAXILLOFACIAL INJURY: CONCEPTUAL DESIGN OF FOUR PROTOTYPES DERIVED FROM BIOMECHANICAL ANALYSIS

Facial protectors are widely used in sport and at work, but most are designed for a single activity and protect a fixed set of structures. The mechanism of injury, however, determines which parts of the facial skeleton are loaded and where they fail, so protection that is not matched to the mechanism may leave the most vulnerable regions exposed. Aim–To derive protection priorities for four common injury mechanisms from clinical, computed-tomographic, and finite element data and to translate them into conceptual designs for protective headgear. Three sources were combined: the anatomical distribution of fractures in patients with combined maxillofacial trauma caused by road traffic accidents, falls from height, sports injuries, and multifactorial trauma; regional radiodensity in Hounsfield units, used as a computed-tomography surrogate for bone mineral density, and porosity of the facial skeleton; and finite element simulation of frontal, lateral, and oblique impacts at 5–10 m/s, with calculation of the Head Injury Criterion (HIC). For each mechanism, anatomical regions were ranked by fracture frequency, mechanical vulnerability, and contribution to head-injury risk, and the resulting priority zones were expressed as four conceptual three-dimensional designs. Fracture distribution differed clearly between mechanisms: road traffic accidents produced predominantly midfacial injuries of Le Fort I–II type, with orbital floor and zygomatic fractures; falls from height produced nasal and orbital floor fractures; sports injuries produced isolated nasal and zygomatic fractures; and multifactorial trauma produced multiregional injuries involving the mandible, frontal bone, and midface. The orbital floor (590±65 HU) and nasal bones (510±60 HU) were the least dense and most porous regions, while the temporal region carried the highest head-injury risk on simulation (HIC 1620±260 for lateral impact versus 1380±210 for frontal, 1250±180 for parietal, and 1100±160 for occipital impacts). Four prototypes were designed accordingly: a closed design protecting the lower face and lateral region for road traffic use; a lightweight open frame protecting the nose, malar region, and temple for fall-prone settings; an open sports design protecting the nose, malar region, and jaw while preserving the visual field and ventilation; and a full design additionally covering the frontal and temporal regions for mixed high-energy exposure. The system has been registered (FAP20260186). Injury mechanism can be used as the organising principle for facial protection. The four designs presented here translate measured fracture distribution, regional bone vulnerability, and simulated impact risk into distinct coverage patterns. They are conceptual: material selection, impact testing against recognised standards, and field evaluation of protective efficacy remain to be carried out.

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