Wires

40 finished cases (20 Roth, 20 MBT): nine experienced orthodontists scored them alike (P = 0.900) and named the prescription no better than chance (kappa 0.25). Laser scans of the same models: no difference in final incisor and canine inclination (P = .132); about 180 patients would be needed to detect 5°. A third study found MBT slightly better, not clinically significant.

Randomized trial, 153 patients: 29.3 vs 31.2 months; same quality (PAR reduction 74.1% vs 77.1%), root resorption and anchorage loss (P = .970). Two systematic reviews agree; certainty low to very low.

Randomized trial, 105 patients: no difference in upper incisor inclination change. CBCT, 46 patients: lower incisors proclined with both active and passive designs; the claimed control could not be demonstrated. In the lab, conventional ligation expressed the most torque in 3 of 7 comparisons.

Lab only: torque started at 7.5° of twist (active) vs 15° (passive) with 19×25 steel; a review gives about 7.5° vs 14°. A clinical difference has not been shown, and one rig found the clip adds only about 1 Nmm.

32 extraction patients (16 high-torque Damon Q, 16 standard): no significant difference in apical root resorption on CBCT (retrospective).

Roth-treated digital models: final crown inclination and angulation did not match the bracket values for most teeth (26 patients). A calculation study found common upper incisor torque values do not reliably produce normal incisor inclinations. Same-name brackets from different makers differed by 2.13–3.90° in measured tip.

600 teeth: differences between patients or in bracket height exceed the differences between standard torque prescriptions. 107 finished cases: at one bracket height the tooth-to-bracket angle spread 21.0° (U1) and 20.0° (L1). Crown–root angle ranges 171–195° in incisors and 167–195° in canines. Play of 16×22 in .018 (about 14°) or 19×25 in .022 is larger than the whole Roth–MBT torque difference; even 17×25 in .018 leaves about 6°, the same size as that difference.

Case reports of one patient each: inverted upper incisor brackets reduced upper incisor inclination from 126.31° to 115.67° over 25 months; an inverted upper central bracket brought a palatal canine root labially over 20 months. Otherwise technique articles; no trial.

Direct (typodont): 0.34 mm and 5.54° mean error. Indirect transfer (ex vivo, pooled): 0.08–0.14 mm and about 1°. An older trial found similar errors; a 2024 split-mouth trial found digital indirect closer to the plan (0.38 mm / 3.40° vs 0.73 mm / 8.24°).

Slots are usually oversized (all 11 systems in one test). Commercial MBT upper central brackets measured 7.67–17.81° torque against a stated 17° and 1.67–6° tip against 4° (review of 20 studies). Four systems failed ISO 27020 limits in another test.

Lab: no difference below 12° of twist; beyond 24°, steel 1.5–2 times TMA and 2.5–3 times NiTi. In conventional brackets at 15°, 17×25 in .018 gave 14.2 Nmm (steel) vs 9.25 Nmm (TMA). One study found no steel–NiTi difference.

Systematic review, 4 studies: no significant differences in treatment duration, outcome or patient satisfaction; stock appliances showed more lower incisor proclination and more bracket repositioning.