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Every number on this page carries its sign: + torque = crown labial, root lingual; + tip = crown mesial.
What the bracket does seen from above. In-out is how far the slot stands off the tooth (base thickness); rotation or offset is a built-in turn. Together they line up the labial faces on a straight wire and keep molars from rotating into extra arch space.
The slot tilted mesiodistally, seen from the front. A full wire in that slot sets the crown's mesiodistal angulation: crown mesial, root distal.
Sign
+ tip = crown tipped mesially (the gingival end of the long axis lies distal).
The slot's labiolingual angle, seen from the side. A rectangular wire twisted in the slot turns the crown one way and the root the other. Round wires turn freely and carry no torque.
Sign
+ torque = crown labial or buccal, root palatal or lingual. − torque = crown lingual, root labial.
Upper incisors carry positive torque; canines, premolars and molars mostly negative; lower posterior torque grows more negative toward the back. Some documents print torque without a sign: a lower premolar listed as '12°' means −12°.
Sign
Every value on this page carries its sign.
The straight-wire design builds torque into the base, so slot centre, base centre and FA point line up. Damon Q2 keeps torque in the base; Damon Ultima puts it in the slot, which levels the upper incisor slots. In one lab test a torque-in-slot self-ligating bracket expressed torque like a conventional bracket and better than a torque-in-base one.
A rectangular wire smaller than the slot must twist through an angle before it touches both slot walls; until then the bracket's torque does nothing. That angle is the play. Measured play is always larger than geometry predicts, because wire edges are rounded and slots oversized. Some sources quote it one way, others both ways (twice the number).
In-out is the base-to-slot depth. Thin crowns get thicker brackets: in one MBT line U1 1.02 mm, U2 1.24 mm, U3 0.81 mm. Offset is a built-in first-order angle, mostly on molar tubes (MBT upper molars 10° distal offset, lower 0°). Prescriptions differ mainly in tip and torque, much less in in-out.
The facial axis of the clinical crown (FACC) runs along the most prominent central ridge of the labial face; on molars, along the buccal groove. Its midpoint is the FA point; the LA point is the same crown centre under another name. The prescriptions assume a bracket centred there. No point is constant between teeth of the same type, so what a bracket expresses still varies.