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Placement heights: the distance from the incisal edge or cusp tip to the slot, in millimetres.
| Tooth | mm |
|---|---|
| U1 | 5.0 |
| U2 | 4.5 |
| U3 | 5.0 |
| U4 | 4.5 |
| U5 | 4.0 |
| U6 | 3.0 |
| U7 | 2.0 |
| L1 | 4.0 |
| L2 | 4.0 |
| L3 | 4.5 |
| L4 | 4.0 |
| L5 | 3.5 |
| L6 | 2.5 |
| L7 | 2.5 |
Measure each fully erupted crown on the model, halve it, round to 0.5 mm and pick the row holding most of the values. Rows A and B are +1.0 and +0.5 mm for larger crowns (U1 6.0 and 5.5); rows D and E are −0.5 and −1.0 mm (U1 4.5 and 4.0). U7 stays 2.0 in every row and the lower molars stop at 2.0. Deep or open bite: use a posterior row next to the anterior row. Extraction cases: a different posterior row avoids a step beside the space.
3M documents disagree on premolars: the IFU prints them; the 2012 brochure and a later handbook leave them blank and set premolars from the molar's marginal-ridge distance. A practitioner shortcut matches the upper average row: central = crown height ÷ 2, lateral 0.5 mm less, canine = central, each premolar 0.5 mm less, first molar 1 mm less than U5 (upper arch only).
| Tooth | mm |
|---|---|
| U1 | 6.5 smile creation / 5.5 smile preservation |
| U2 | 5.5 / 5.2 |
| U3 | 5.0 / 5.0 |
| U4 | 4.5 / 4.5 |
| U5 | 4.0 / 4.0 |
| U6 | 3.5 / 3.5 |
| Lower incisors and premolars | 4.0 |
| L3 | 4.5 |
Two separate schemes. Smile creation bonds the upper incisors high (gingival) to extrude them and build a smile arc; smile preservation keeps an existing arc. Heights fall from front to back.
One practitioner source. The anterior steps match independent smile-arc reports (central about 1.5 mm more gingival than the canine); the posterior and lower values have no independent support. An older Damon generation used U1 4.75, U2 4.50, U3 5.00, U4 4.50, U5 4.25 mm, lower the same, with the canine bracket further from the edge than the central's, which tends to flatten the smile arc (B0317). The Damon quick guide's 'green zone' (central 5–6 mm, lateral and canine 4.5–5.5 mm) claims placement anywhere inside it barely changes torque; measured data (about 2–4° per mm on incisors) say otherwise.
| Tooth | mm |
|---|---|
| U1 | 4.0 |
| U2 | 3.5 |
| U3 | 4.5 |
| U4/U5 | 4.0 |
| L1/L2 | 3.5 |
| L3 | 4.0 |
| L4/L5 | 4.0 |
Oriented jigs are colour-coded: 3.5 mm blue, 4 mm red, 4.5 mm yellow, 5 mm green (the 5 mm jig for canines only).
For Tip-Edge PLUS only. The same maker's straight-wire lines set the second premolar at 3.5 mm.
| Tooth | mm |
|---|---|
| U1 | 5.0 |
| U2 | 4.0–4.5 |
| U3 | 5.0 |
| U4 | 4.5 |
| U5 | 4.0 |
| U6 | 3.5 |
| U7 | 3.0 |
| L1/L2 | 4.0 |
| L3 | 5.0 |
| L4/L5 | 4.0 |
| L6/L7 | 3.5 |
Keyed to the upper central's FA height: canine at the central's height, lateral 0.5–1 mm less, each tooth behind 0.5 mm less than the one in front. Lower canine at the upper central's height, lower incisors and premolars 1 mm less, molars 0.5 mm less than the premolars. Extra rows at +1, +0.5 and −0.5 mm.
Evidence is one 13-year-old case. The authors argue the MBT chart does not level marginal ridges; that claim is unverified.
Centre the slot on the FA point with the bracket's vertical line on the long axis; the slot is perpendicular to that axis and the wings parallel to it. Upper molar tubes sit on the buccal groove, lower tubes on the mesiobuccal groove, parallel to the buccal cusps with equal cusp showing either side.
What it does
The built-in tip, torque and in-out express as designed only from here, on an average crown with a near-full-size wire. Crown shape still varies: differences between patients and in bracket height exceed the differences between prescriptions.
A bracket gingival to the crown centre extrudes the tooth when a straight wire levels the slots. A molar tube or band seated too gingivally (often over-seated palatally) extrudes the molar, steps its marginal ridge and reduces the overbite.
What it does
On a convex crown it also changes torque. On a lower first premolar, more gingival placement adds lingual crown torque. On upper incisors the sources disagree on direction: a finite-element model found the torque moment rising as the bracket moved gingivally, while a smile-arc protocol reports the criticism that gingival placement lowers the effective torque in the slot.
Numbers
Lower first premolar: labial surface angle changes 26.39° between 2.5 and 6 mm from the cusp tip. Upper central (model, Damon Q): 9.03 Nmm at 5 mm rising to 14.11 Nmm at 8 mm.
An occlusal bracket intrudes the tooth. Partly erupted premolars and lower second molars, inflamed gingiva and palatally displaced roots all hide crown, so the eye places the bracket too occlusally. Bond partly erupted premolars more gingivally and rebond as they erupt.
What it does
Premolars: marginal-ridge step against the molar, poor interdigitation, a local open bite. Upper lateral too incisal: a step between the central and canine edges. On a lower first premolar, occlusal placement gives buccal crown torque.
An off-centre bracket rotates the tooth: the side carrying the bracket comes out to the wire. Canines: bond slightly mesial of the mesiodistal centre, on the most convex surface (the true FA point). Upper premolars: some bond slightly mesial to turn the buccal cusp distally toward Class I.
What it does
Curved crowns (canines, premolars) rotate most; flat incisors and molars tolerate small errors. A canine bracket at dead centre or distal leaves the canine rotated mesial-in, which complicates a lower fixed retainer. Rotated and displaced teeth attract this error in the first place.
Numbers
The upper premolar figure of about 0.5 mm mesial is a practitioner value only.
Keep the wings parallel to the crown's long axis. A tilted bracket gives the wrong tip; on an upper central it also adds a rotational error.
What it does
Tip and torque are coupled at the front: about 1° of mesial crown tip is lost for every 4° of palatal root torque added (shown as 20° → 5° and 40° → 10°), which is why straight-wire prescriptions carry extra front-tooth tip.
Numbers
On typodonts, clinicians tended to bond with a distal tip: mean errors −1.61° (crown-centre method) and −1.35° (measured height).
Press the bracket fully home so excess composite flows out, and remove the flash before curing.
What it does
An even thick layer mainly pushes the bracket out (in-out). A wedge-shaped layer tilts it: thicker at the gingival or incisal edge changes torque; thicker at the mesial or distal edge changes rotation. Unseated lower incisor brackets showed rotation errors once a rectangular NiTi went in.
Numbers
No study isolates adhesive thickness against torque; this is a maker statement plus geometry.
Seat tubes parallel to the buccal cusps. That line already gives the upper molar about 5° of tip and the lower about 2°, so MBT tubes carry 0°. Offset turns the molar so it does not rotate mesiopalatally and take arch space. In high-angle cases bond the second-molar tube more occlusally, or delay it.
What it does
A 5° upper tube seated parallel to the cusps gives about 10°: the crown tips too far mesially and the distal cusps hang into occlusion. Too little upper offset leaves the molar rotated mesial-in. An occlusal second-molar tube stops it extruding and opening the bite.
Numbers
Offset: MBT upper 10°, lower 0°; one textbook asks at least 10° upper and 5–7° lower; set-ups measured about 7°. Second-molar tube about 0.5–1.5 mm occlusal to the first-molar tube; the MBT chart puts U7 at 2.0 mm in every row.
Deep bite: incisor and canine brackets 0.5 mm more incisal (some also put the posteriors 0.5 mm gingival). Open bite: incisor and canine brackets 0.5 mm more gingival. The 3M chart does the same by choosing a posterior row next to the anterior row.
What it does
As the wire levels, incisal brackets intrude the incisors and gingival posterior brackets extrude the posteriors; gingival anterior brackets extrude the incisors. Posterior extrusion suits short faces only and is of doubtful stability in non-growers.
Numbers
0.5 mm is MBT convention; independent sources say only 'slightly'. 1 mm of molar extrusion reduces overbite by 1.5–2.5 mm.
Traditional guideline: lateral about 0.5 mm closer to the incisal edge than the central, canine about 0.5 mm more apical (the source does not say more apical than which tooth; read against the lateral, the canine sits level with the central, as on the MBT chart). Smile-arc schemes do the opposite: Damon's guide puts the central about 1 mm more gingival than the canine with the lateral between (flat arc: lateral 0.5 mm gingival to canine, central 0.5 mm gingival to lateral); a smile-arc protection protocol puts the central about 1.5 mm more gingival than the canine and the lateral 0.75–1 mm more incisal than the central.
What it does
Gingival incisor brackets extrude the incisors relative to the canines so their edges follow the lower lip. One randomized trial (42 patients, Roth .018): the smile arc improved with the protective scheme (P = 0.005), with no difference in occlusal measures.
Numbers
A 0.5 mm central–lateral bracket step is chosen by 78.3% of 434 surveyed orthodontists; esthetic studies prefer a 1.0–2.0 mm incisal step.
Canine moved into a missing lateral's site: bond it more gingivally (judge by the gingival margin, not the cusp tip) to extrude it, then reduce the cusp. First premolar in the canine site: bond more occlusally to intrude it so its gingival margin rises like a canine's.
What it does
Extrusion lowers the canine's gingival margin toward a lateral's; intrusion lifts the premolar's. Bracket choice for these teeth is in the tricks below.
In Class III camouflage with low upper incisor display, bond the upper anterior brackets more gingivally from the start rather than repositioning them later.
What it does
Gingival placement extrudes the upper incisors, increasing incisor display and smile-arc curvature.
Numbers
No measured outcome: single-case hindsight plus convention.
On the side that has dropped and must intrude, bond the anterior brackets more incisally than on the other side (for example 3 mm against 4 mm from the incisal edge). Bonding that side more gingivally would extrude it and worsen the cant.
What it does
Corrects small dental cants only; skeletal cants need TADs, an asymmetric intrusion arch or surgery.
Numbers
Practitioner limits disagree: about 1–3 mm in one source, 2–4 mm in another. Neither is verified.
Aim for 0.5 mm and 2°. That target is a grading convention borrowed from finished-case scoring, never validated as a biological limit.
What it does
Free-hand bonding usually misses it vertically. Measuring from the incisal edge was slightly more accurate vertically than eyeballing the crown centre. Indirect bonding transfers a plan closely; its least accurate direction is vertical.
Numbers
Direct, faculty on typodonts: 0.34 mm and 5.54°. Orthodontists 1.19 ± 0.23 mm vertical vs final-year students 0.90 ± 0.21 mm (students slower: 50.65 vs 28.53 min). Incisal-edge method 1.10 vs crown centre 1.19 mm. Indirect transfer (ex vivo, pooled): 0.08 mm mesiodistal, 0.09 mm buccolingual, 0.14 mm vertical; 1.13° tip, 0.93° rotation, 1.11° torque. Randomized split-mouth: digital indirect 0.38 mm / 3.40° vs direct 0.73 mm / 8.24°.
Every millimetre of vertical error changes the torque the tooth receives, because the base follows a curved surface. Lower incisors change least; premolars and molars most.
What it does
The often-quoted '1 mm ≈ 10°' is a second-hand figure that overstates the typical change. Treat it as a ceiling, not a rule.
Numbers
Lower teeth, per 1 mm: about 2° incisors, 3° canines, 8° premolars and molars (table means 3.34° central, 2.77° lateral, 3.75° canine, 7.70–8.44° premolars and molars). Per 0.5 mm: 1.3° (lower front) to 3.3° (lower molars). Upper incisors and canines: about 10° between 2 and 4.5 mm from the edge (about 4° per mm). Finished cases: 4.5° (U1) and 3.2° (L1) over 2 mm. Lower first premolar: 26.39° over 3.5 mm.
Place the bracket at the centre of the intended crown, not the worn or broken one: match the intact tooth on the other side, measured from the planned edge. Bond gingival to the centre if the edge will be reduced. Long crowns (often facially displaced canine roots) tempt a too-gingival bracket; short crowns a too-occlusal one.
What it does
Levels the tooth to its final crown form instead of its present one. A pulp-involved fracture needs treatment first; only then may a build-up wait.
The textbook names two checkpoints. The end of stage 1 — round superelastic wires for 8–12 weeks, then a 0.020×0.020 thermal wire for 8–10 weeks — is the first time to evaluate bracket placement and debond or rebond, before stage 2; at finishing, once the occlusal planes are parallel and the slots aligned, check again and consider a second debond-rebond. Another textbook assesses root parallelism at progress records about three-quarters of the way through treatment. Practitioner protocols take one panoramic radiograph and reposition: one visit after the working NiTi goes in; 10 weeks into the 14×25 copper NiTi stage; or a 2–3-month check-and-reposition stage after 18×25 CuNiTi, before the 19×25 / 16×25 steel. In case logs the radiograph falls at 4 months 3 weeks in one case and 7 months 2 weeks in another.
What it does
Review bracket position critically during initial alignment: an error caught early may avoid complex finishing bends and a longer treatment (textbook). No source gives a frequency or a maximum number of rebonds; the textbook's wording implies two.
Numbers
Stage 1: round superelastic 8–12 wk, then 20×20 thermal 8–10 wk; root parallelism at about ¾ of treatment; the practitioner panoramic one visit after the working wire, at 10 wk of the 14×25 stage, or as a 2–3-month stage; case logs 4 mo 3 wk and 7 mo 2 wk.
The textbook calls the panoramic check of root angulation contested: the view is accurate to within 2.5° in only 26% of instances, projects the upper canine–first premolar roots as more divergent than they are, and distorts the lower lateral–canine roots.
What it does
In a published study of 864 teeth from 36 patients, read by two orthodontists, decisions on whether to reposition agreed between panoramic and cone-beam images in 73.7–84.5% of cases; against the cone-beam decision, 78.9% of panoramic decisions matched, 9.3% would have missed a repositioning and 11.3% would have repositioned unnecessarily. The authors' conclusion: comparable reliability and substantial agreement.
Numbers
Within 2.5° in 26% (textbook); agreement 73.7–84.5%; 78.9% coincident, 9.3% missed, 11.3% unnecessary (study).
At finishing, the textbook rebonds a poorly positioned bracket rather than placing compensating bends — time-efficient, especially for inclination errors — and follows with a flexible wire, because rectangular steel is too stiff in bending: 17×25 beta-titanium in an .018 slot, 21×25 M-NiTi in a .022 slot. Another textbook uses nickel-titanium, TMA or light steel for first- or second-order problems where brackets were repositioned, and round .018 steel or TMA where they were not. Re-bracketing may require dropping down the archwire sequence (textbook, hypodontia).
What it does
Practitioner routines agree in direction: drop back to .018 round copper NiTi if brackets were drastically repositioned; after rebonding a bracket slightly higher, a rectangular NiTi for 15–20 days while the tooth settles; minor finishing repositioning is done even with the steel wire in place. One practitioner case log is the counter-example — brackets rebonded at 2 months 2 weeks while the NiTi wires kept advancing.
Numbers
A vertical error of up to 1 mm can change inclination by 10° (textbook): check the height at every rebond. 17×25 β-Ti (.018) or 21×25 M-NiTi (.022) after a finishing rebond; .018 CuNiTi after drastic repositioning; rectangular NiTi 15–20 days.
The textbook's protocol for a loose metal bracket: replace it if the slot is deformed; remove the adhesive from the tooth with a tungsten carbide bur; sandblast the base; etch 15 seconds; prime and rebond; religate the neighbours first. Sandblasted rebonded brackets perform comparably to new ones; bond strength falls with larger sandblasting particles and with repeated recycling. A loose ceramic bracket is best replaced with a new, intact one.
What it does
Published numbers: in a split-mouth trial of 80 rebonded premolar brackets followed 6 months, 10% failed after sandblasting plus etching and 25% after etching alone (in vitro 19.38 MPa initial, 22.37 sandblast-plus-etch, 17.31 etch-only). A meta-analysis of 16 in vitro studies put new and sandblasted metal brackets 0.85 MPa apart (clinically negligible); another found rebonded brackets weaker after air abrasion, grinding or flaming, similar after Er:YAG laser, all clinically acceptable; three bond–debond cycles on the same teeth stayed above the 6 MPa clinical floor. Reconditioned ceramic brackets have in vitro data only: 2.97 MPa after sandblasting against 15.66 MPa new. Time: each failed bracket added about 0.6 months in a 78-patient cohort (14.1% of brackets failed; ceramic brackets failed more, hazard ratio 1.62), and brackets rebonded for repositioning were a significant factor in a 366-patient treatment-time model. No source gives chair minutes per rebond.
Numbers
10% vs 25% failures at 6 months (sandblast-plus-etch vs etch); new vs sandblasted 0.85 MPa apart; ≥6 MPa over three cycles; ceramic rebond 2.97 vs 15.66 MPa new (in vitro); +0.6 months per failed bracket; 3–6 months when severely rotated premolars in hypodontia need repeated repositioning.
Molar bands may be less prone to failure than bonded tubes: the textbook uses them where buccal tubes fail repeatedly, particularly on heavily restored or misshapen teeth, and another textbook, where bond failures recur, considers bands with pre-soldered brackets or a composite build-up of the labial surface. The reverse switch appears once: a practitioner source replaces a band with a bonded attachment when gingival health is compromised during molar intrusion.
What it does
A second molar banded or bonded late is aligned with a flexible segment from the first molar's auxiliary tube while the rest of the arch keeps its heavier wire; the continuous archwire is extended once it is aligned (textbook). Band to bonded tube mid-treatment for any other reason: no source.
Changing slot size (.018 ↔ .022) for the whole appliance part-way through a case: no textbook, practitioner source, company document or published study describes it. The textbook lists a .018 slot in the anterior segment as an alternative when third-order control is lost to play (19×25 in .022 plays 7.24°; 17×25 in .018, 2.32°) — without saying whether it is chosen at bonding or switched to. Changing the bracket system mid-treatment (conventional twin ↔ self-ligating, twin ↔ Tip-Edge): no procedure, wire step or outcome in any source. One practitioner case judged a self-ligating system would have been the better first choice and continued in its .022 twin appliance; a trial protocol notes that a patient transferring to an orthodontist who uses the other slot is inconvenient and may face a longer treatment, without data.
What it does
Before continuing a transferred case, check which archwire is in — NiTi or steel — so you do not retract on a NiTi mistaken for steel (practitioner). Metal ↔ ceramic: only single-tooth swaps are described (see the tricks). No source measures the time cost of a deliberate mid-treatment swap; the published 0.6 months is per failed bracket.