Type-level market taxonomy differentiates sheets by Shore hardness and subsequent forming behavior. Soft-grade (85–90 A) variants hold 61 % volume share; their low modulus enables deep draws over 0.3 mm tooth undercuts without webbing, making them the default for mild-to-moderate crowding cases. Medium-grade (90–95 A), 27 %, balances stiffness and drapability, preferred when auxiliary engagers or precision cuts are incorporated because the sheet resists flex-crack propagation during die-punching. Hard-grade (≥95 A), 12 %, is reserved for revision or retention appliances where higher yield stress (≥18 MPa) maintains anchorage in posterior regions. Thickness sub-classes (0.5 mm, 0.625 mm, 0.75 mm, 1.0 mm) are not standalone SKUs but are mapped to the hardness tiers—thicker hard-grade sheets command 18 % price premium per kg due to increased TPU density and longer cooling-lot residence time, explaining why suppliers limit hard-grade SKU breadth to protect contribution margin.