Archwire sequences as companies and practitioners use them.
1Aligning — round NiTi
Aligning wires
Sizes
.014 NiTi / CuNiTi first (.012 NiTi if the .014 cannot engage), then .016 or .018 NiTi / CuNiTi
What it does
The .014 begins leveling and unravelling with about 50 g; most of the irregularity resolves on it in the first eight weeks. The .016 or .018 then finishes leveling and the rotations the first wire could not reach. Still round, still no torque.
How long
About one to two months on the .014, then about one month on the second round wire; visits every three to four weeks.
By system
Conventional twin brackets: .014, then often .016 or .018 NiTi.
Damon Q (passive self-ligating; Ultima differs): .014 CuNiTi (.013 if very crowded), left in 10–20 weeks at 10-week visits; the .018 CuNiTi follows for everyone, 6–8 weeks.
2Rotations, leveling, early torque — rectangular NiTi
Watch out · 1
Rectangular NiTi / CuNiTi
Sizes
16×22 NiTi (the usual step); 17×25, 18×25 or 19×25 NiTi in some sequences
What it does
Completes rotations, flattens the curve of Spee, shapes the arch form, starts torque. Slot play in a .022 slot: 16×22 about 18°, 17×25 about 12°, 19×25 about 7–10°, 21×25 about 2°.
How long
'A couple of months' on the 16×22 NiTi.
3Working wire — stainless steel
Stiff and low-friction: space closure by sliding, arch form held, bite control, and the base for elastics and anchorage.Watch out · 2
4Finishing and settling
The final small bends, root paralleling, and bite settling.Watch out · 2
5Special wires — only in the cases that call for them
Wires with a job of their own, used only in the cases that call for them.Watch out · 8
Reference dated 2026-10-19.
End-on, to scale, the slot open labially. A sharp-edged 16×22 wire turns 18° in a .022 slot before its corners touch both walls (dots); until then the bracket's torque does nothing. That is the ideal geometry; the reference's clinical figure is also about 18°, and rounded edges and oversized slots add more. For comparison, to scale: 19×25 about 7–10°, 21×25 about 2°. Dashed: the wire untwisted.
By system
Conventional twin brackets: 16×22 NiTi is the common rectangular step; several teachers avoid 17×25 NiTi during alignment because of root-resorption risk.
Damon Q (passive self-ligating; Ultima differs): 14×25 CuNiTi 10 weeks, then 18×25 CuNiTi 4–6 weeks (a 16×25 can replace either) — rectangular CuNiTi early by design; the panoramic X-ray and bracket repositioning come after about ten weeks on the 14×25.
Other systems: .018 slot: 17×25 NiTi for leveling, 16×22 steel for retraction.
Watch out
Never put a reverse curve into a rectangular wire before the arch is level — it torques the lower incisor roots lingually.
Sources (5)
TextbookB0015
TextbookB0207 p.555
PractitionerL0302
PractitionerB0301 p.8
CompanyDamon System Quick Start Guide
In plain words: The wire is smaller than the slot is tall, so it can twist a little before its corners catch the walls — that free twist is play, and it does nothing to the tooth. Only after the corners catch does your twist become torque: the force that moves the ROOT through the bone. A fuller wire catches sooner, so more of your twist reaches the root — thin wires level crowns; torque work waits for full-size wires.
Upper right segment, front to the right. The stiff steel working wire stays straight while the canine bracket slides back along it (arrow), pulled by a NiTi coil spring across the extraction space.
Stainless steel working wire
Sizes
.022 slot: 19×25 SS (standard); some clinicians close on 16×22 or 17×25 SS. .018 slot: 17×25 SS.
What it does
Lets the wire sit passive four to six weeks, then closes space. Measured closure: about 0.8 mm per month with a NiTi coil, 0.6 with an elastomeric chain, 0.35 with an active ligature.
How long
Passive four to six weeks, then closure: four to five months in extraction cases, often longer with loops.
Space closes on steel: three drives on a stiff steel working wire, each with its measured closure — NiTi coil about 0.8 mm a month, elastomeric chain 0.6, active ligature 0.35 (arrow lengths in proportion). Never close space on NiTi or on a round wire.
By system
Conventional twin brackets: Chain changed every two to four weeks; the lower arch is often retracted a few weeks before the upper.
Damon Q (passive self-ligating; Ultima differs): Posted 19×25 SS upper / 16×25 SS lower; nonextraction 20–30 weeks; visits never longer than eight weeks to avoid over-correction.
Watch out
Never close space on NiTi or on a round wire.
Which steel to close on is contested — 16×22 (less friction), 17×25 minimum, or 19×25 (more control). No trial settles it.
Sources (5)
TextbookB0050 p.97
TextbookB0208 p.570
PractitionerL0276
PractitionerL0242
CompanyDamon treatment protocol sheets
Left: the final small bends go into TMA (β-titanium), which holds a bend with gentler force than steel — the step seats the third tooth. Right: settling on a light round wire, a vertical elastic draws the upper and lower teeth into contact (arrows). Vertical elastics for no longer than six weeks.
Finishing and settling wires
Sizes
TMA (β-Ti) 17×25 / 19×25 / 21×25; braided rectangular SS; light round .014–.018 SS for settling
What it does
TMA holds bends with gentler force than steel; 21×25 TMA gives nearly full torque expression. Settling runs on a braided or light round wire with vertical elastics.
How long
Two to four months in total. Vertical elastics no longer than six weeks; some clinicians settle two to three months on 19×25 steel with a crisscross ligature.
Left: the same small bend in β-titanium (TMA) and in steel. TMA holds it like steel but delivers a gentler force — arrow weight, not length, marks the force. Right, end-on and to scale: a 21×25 TMA wire nearly fills the .022 slot, about 2° of play, so it gives nearly full torque expression.
Watch out
Avoid a solid 21×25 steel wire except after β-Ti.
Never exceed 19×25 in a .022 self-ligating slot.
Sources (5)
TextbookB0209 p.598
TextbookB0051
TextbookB0029 p.463
PractitionerL0311
PractitionerB0304
Lower arch, unrolled, front to the right. The relaxed reverse-curve wire lies gingival to the incisor brackets and occlusal to the premolar and molar brackets (dashed: the bracket line), so engaging it presses the incisors apically — about 1 mm of intrusion — and lifts the premolars and molars: relative intrusion. The curve is factory-made: NiTi cannot be hand-bent. Curves and movements enlarged.
Reverse-curve NiTi (preformed)
Sizes
.016–.020 round; 16×22 up to 21×25; some with 20° anterior torque built in
What it does
Deep-bite leveling by relative intrusion: incisors intrude about 1 mm, premolars and molars extrude. NiTi cannot be hand-bent, so the curve is factory-made.
How long
A trial measured about 4.9 months on a lower 16×22 NiTi reverse curve; some clinicians keep it three to four months.
Lower arch only. Top, correct: the relaxed curve lies gingival to the incisor brackets and occlusal to the back teeth, so it intrudes the incisors and extrudes premolars and molars. Bottom left: it also proclines the lower incisors about 5–6° (dashed: before); a steel reverse curve without labial crown torque does not. Bottom right, struck: the commonest error, the wire seated reversed — the curve then lies above the incisors and deepens the bite. Not for high-angle, long-face patients: it levels by extruding the back teeth.
By system
Damon Q (passive self-ligating; Ultima differs): The Damon sheets give 4–10 weeks on the reverse-curve wire. The 20°-torque version is for Class II division 2 where intrusion AND torque are wanted; the plain version when only intrusion is wanted.
Watch out
Lower arch only in deep bite — an upper reverse curve flattens the smile arc.
Not for high-angle, long-face patients: it levels by extruding the back teeth.
It proclines the lower incisors about 5–6°; a steel reverse curve without labial crown torque does not (about 0°).
Not fail-safe — the curve is usually excessive; see the patient often. Check the orientation: the commonest error is seating it reversed.
Anterior bite turbos reduced the overbite as much and about 1.7 months faster in the one head-to-head trial.
.016 / .018 round; 17×25, 18×25, 19×25 rectangular; curve about 3–4 mm deep at the premolars
What it does
Hand-bent bite control, especially while closing extraction space: it fights the roller-coaster deepening as the incisors retract.
How long
Rides on the working wire; no separate stage.
Coated (tooth-coloured) wires
Sizes
Same sizes as the metal wires they coat
What it does
Aesthetic option with ceramic brackets. Adults rate white-coated wires as highly as clear ones.
How long
No separate timing stated anywhere.
A coated wire across two incisors, its coating worn through mid-span: the coating wears off and exposes metal. Coated wires also stain, break more and bend poorly — several clinicians avoid them.
Both arches unrolled about the occlusal plane, front to the right. The convention: an accentuated curve in the upper wire and a reverse curve in the lower, each about 3–4 mm deep at the premolars. Both relaxed front segments lie gingival to their bracket lines (dotted) — up in the upper, down in the lower — so the same intrusive intent looks like one curve mirrored. Cinch the wire back behind the molar tube: a reverse curve increases flaring. Curves enlarged.
Watch out
Cinch the wire back — a reverse curve increases flaring.
Accentuated curve in the upper, reverse curve in the lower is the convention.
Sources (4)
TextbookB0049 p.91
TextbookB0207 p.555
PractitionerL0250
PractitionerL0024
Watch out
The coating wears off and exposes metal; coated wires stain, break more, and bend poorly — several clinicians avoid them.
