Table 1. Characteristics of included studies.

Bhattarai 2011 [30]

rNRS; Uni; NP

AD: 134 (NR); 13.6

ADU: 46 (NR); 23.1

No impactions, 2-phase Tx, or non-compliant patients; all permanent teeth except M3

Full Tx

NR

Roth FA 0.018” (loops, elastics; HG)

NR

Dyer 1991 [1]

rNRS; Pract; US

AD: 30 (0/30); 12.5

ADU: 26 (0/26); 27.6

Cl. II/1; all permanent teeth except M3

Full Tx

≥ ½ Cl. II MR

SE FA 0.022” (elastics, HG, sliding jigs)

4xPM

Furquim 2018 [31]

rNRS; Pract; BR

AD: 23 (10/13); 11.8

ADU: 16 (7/9); 22.4

Cl. II

Full Tx

NR

FA and MPA

NR

Harris 1990 [32]

rNRS; Pract; US

AD^c: 29 (0/29); 12.5

ADU^c: 30 (0/30); 27.9

Cl. II/1; all permanent teeth except M3

Full Tx

≥ ½ Cl. II MR

FA (SDFET)

4xPM

Iancu 2018 [33]

rNRS; Uni; IT

AD: 19 (8/11); 13.8

ADU: 3 (2/1); 23.7

PDC

PDC alignment

NR

OSE; FA 0.022 (TPA, CAN)

NR

Jiang 2017 [34]

pNRS; Uni; US

AD: 10 (6/4); 14.7

ADU: 8 (1/7); 25.1

Need for Mx canine retraction

Canine retraction

NR

FA 0.019” (T-loops 124cN; TPA)

2x Mx PM

Loke 2012 [35]

rNRS; Pract; MY

AD^c: 716 (NR); NR

ADU^c: 156 (NR); NR

No syndromes, CLP, or only RFA; Cl. I (28%), II (57%), III (15%); impactions (7%)

Full Tx

NR

FA ± Mx removable appliance, functional appliance, or surgery

Ex (74%)

Nienkemper 2014 [36]

rNRS; Uni;

DE

AD: 37 (17/20); 12.9

ADU: 14 (4/10); 30.9

≥ ¼ bilateral Cl. II MR or anterior Mx crowding

Full Tx

≥ ¼ Cl. II MR

MI-distalizer

NR

Robb 1998 [37]

rNRS; Pract; US

AD^d: 40 (15/25); 12.9

ADU^d: 32 (12/20); 31.3

Cl. I (94%) or II (6%)

Full Tx

NR

FA

4xPM

Sachdeva 2012 [38]

rNRS; Pract; US

AD: 1861 (NR); NR

ADU: 979 (NR); NR

Cl. I, II, or III

Full Tx

Mean PAR = 25.5

FA

NR

Shim 2011 [39]

rNRS; Pract; KR

AD^c: 70 (35/35); NR

ADU^c: 70 (35/35); NR

No root resorptions, root-fillings, or trauma

Full Tx

NR

SE FA

Ex PM1 (55%)