Monoblock Twin-block Pb
T0 T1 P T0 T1 P
Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Maxillary anteroposterior skeletal
SNA (º) 79.36 (2.93) 79.39 (3.09) 0.000a 80.27 (3.37) 80.5 (3.9) 0.000a 0.269
A-Na Perp. (mm) -0.56 (2.58) -0.06 (3.35) 0.000a 0.53 (2.87) -0.17 (3.12) 0.000a 0.127
Co-A (mm) 73.2 (6.36) 75.88 (7.03) 0.000a 81.65 (5.13) 82.58 (4.72) 0.000a 0.000a
Mandibular anteroposterior skeletal
SNB (º) 74.13 (2.68) 75.06 (3.4) 0.000a 74.4 (2.5) 76.76 (2.94) 0.000a 0.684
Pg-Na Perp. (mm) -7.72 (4.57) -5.74 (6.57) 0.000a -6.42 (4.76) -4.66 (5.65) 0.001a 0.282
Co-Gn (mm) 92.73 (8.14) 99.01 (8.91) 0.000a 101.21 (6.69) 107.15 (7) 0.000a 0.000a
Intermaxillary
ANB (º) 5.23 (1.75) 4.32 (2.09) 0.000a 5.84 (2.12) 3.75 (2.57) 0.000a 0.228
Wits (mm) 3.74 (2.44) 2.15 (2.39) 0.000a 5.80 (2.36) 1.03 (2.85) 0.011a 0.002a
Co-Gn - Co-A (mm) 19.55 (3.4) 23.12 (3.89) 0.000a 19.56 (3.09) 24.59 (4.49) 0.001a 0.987
Vertical skeletal
SGn-FH (º) 60.35 (2.95) 60.07 (3.75) 0.000a 58.42 (3.26) 58.67 (3.3) 0.000a 0.02a
SN-GoGn (º) 31.91 (5.24) 32.37 (5.72) 0.000a 30.03 (5.18) 29.7 (5.23) 0.000a 0.167
FMA (º) 21.88 (4.64) 21.76 (5.45) 0.000a 19.73 (5.39) 20.39 (4.83) 0.000a 0.105
SN-PP (º) 8.3 (3.12) 9.06 (3.32) 0.000a 8.65 (4.02) 8.04 (4.37) 0.000a 0.708
PP-MP (º) 26.51 (4.97) 26.29 (5.05) 0.000a 23.22 (5.61) 23.65 (4.96) 0.000a 0.02a
N-S-Art + S-Art-Go + Art-Go-Me (º) 394.8 (5.45) 395.35 (5.82) 0.000a 391.87 (5.19) 391.7 (5.29) 0.000a 0.037a
S-Go (mm) 65.21 (5.52) 70.12 (7.39) 0.000a 70.85 (6.34) 75.45 (7.05) 0.000a 0.001a
ANS-Me (mm) 56.41 (5.22) 60.72 (5.81) 0.000a 58.11 (5.27) 62.04 (4.82) 0.000a 0.214
NA-APg (º) 8.93 (4.95) 6.83 (5.75) 0.000a 9.18 (5.5) 5.33 (6.23) 0.000a 0.854
PFH/AFH (%) 64.34 (4.47) 66.41 (4.7) 0.883 67.49 (4.74) 68.46 (5.2) 0.03a 0.01a
SN-maxillary occlusal plane 17.54 (5.45) 18.21 (5.607) 0.000a 14.98 (4.29) 16.84 (4.03) 0.000a 0.049a
Maxillary dentoalveolar
U1-SN (º) 101.44 (10.41) 102.77 (6.77) 0.000a 104.69 (12.43) 101.22 (9.28) 0.000a 0.278
U1-OCP (º) 118.97 (7.26) 121 (5.48) 0.099 119.67 (11.24) 118.85 (7.37) 0.002a 0.776
U1-PP (º) 109.73 (9.74) 111.83 (5.84) 0.001a 113.31 (13.58) 109.27 (9.54) 0.000a 0.246
U1-NA (º) 22.08 (9.66) 23.39 (6.18) 0.000a 24.43 (13.12) 20.75 (10.09) 0.000a 0.433
U1-NA (mm) 3.69 (3.34) 4.12 (2.38) 0.000a 4.16 (3.78) 3.18 (3.26) 0.000a 0.612
U1-NF (mm) 25.24 (2.46) 26.52 (2.9) 0.000a 25.07 (3.16) 26.21 (2.6) 0.000a 0.817
U6-NF (mm) 17.46 (1.7) 18.63 (2.15) 0.001a 18.77 (2.16) 19.30 (2.55) 0.001a 0.011a
Mandibular dentoalveolar
L1-MP (º) 97.01 (5.56) 99.17 (5.5) 0.000a 97.38 (6.76) 100.18 (6.36) 0.000a 0.818
L1-NB (º) 25.95 (6.23) 29.58 (5.67) 0.000a 23.67 (6.98) 27.3 (10.23) 0.017a 0.187
L1-NB (mm) 4.06 (2.23) 5.59 (2.07) 0.000a 4.06 (2.23) 5.81 (2.21) 0.000a 0.995
L1-APg (mm) 0.33 (2.15) 2.3 (2.03) 0.000a -0.56 (2.38) 2.63 (2.53) 0.000a 0.134
L1-MP (mm) 30.82 (2.97) 32.64 (3.63) 0.000a 34.93 (3.12) 34.91 (2.62) 0.002a 0.000a
L6-MP (mm) 21.6 (2.47) 23.55 (2.6) 0.000a 24.95 (2.82) 27.95 (5.07) 0.289 0.000a
Interdental
Overjet 6.31 (2.74) 4.31 (1.64) 0.000a 7.65 (2.8) 2.76 (1.44) 0 0.065
Overbite 3.91 (1.93) 2.34 (2.12) 0.001a 4.3 (2.12) 0.64 (2.1) 0.045a 0.463
Interincisal angle (U1-L1) (º) 126.75 (10.87) 122.69 (7.57) 0.001a 126.07 (15.93) 126.51 (10.68) 0.000a 0.846
Soft-tissue profile
Nasolabial angle (º) 110.12 (8.95) 109.72 (9.41) 0.000a 119.47 (9.99) 119.50 (12.35) 0.027a 0.000a
Nasal projection (mm) 11.64 (1.66) 12.61 (1.86) 0.000a 12.33 (3.1) 13.83 (2.04) 0.001a 0.291
Lower lip to E-plane (mm) 0.69 (2.89) 0.34 (2.75) 0.000a -0.59 (2.99) -1.41 (2.85) 0.000a 0.097
Upper lip to E-plane (mm) 0.39 (1.92) -1.31 (1.91) 0.000a -0.91 (2.92) -3.22 (2.88) 0.001a 0.047a
Upper lip anterior (ULA-Sn) (mm) 2.3 (1.83) 1.86 (2.13) 0.000a 0.26 (3.03) 0.06 (2.64) 0.004a 0.003a
Lower lip anterior (LLA-Sn) (mm) -3.62 (2.65) -2.86 (3.08) 0.000a -6.59 (5) -4.26 (4) 0.007a 0.006a
Soft tissue A point’ (A’-Sn) (mm) -1.01 (1.17) -1.49 (1.36) 0.000a -1.97 (2.19) -2.17 (1.92) 0.03a 0.04a
Soft tissue B point’ (B’-Sn) (mm) -11.73 (2.89) -11.35 (3.47) 0.000a -15.26 (6.6) -12.03 (5.43) 0.07a 0.01a
Soft tissue pogonion (Pg’-Sn) (mm) -9.8 (3.21) -9.31 (4.47) 0.000a -13.8 (7.65) -11.33 (6.77) 0.008a 0.012a
Soft tissue convexity (º) 127.42 (3.92) 127.9 (4.27) 0.000a 125.07 (10.35) 126.4 (8.6) 0.518 0.251

aStatistically significant at level P < 0.05 (Paired samples t-test).
bComparison of initial cephalometric measurements between monoblock and twin-block groups.
S = sella; N = nasion; A = A Point (subspinale); B = B point (supramentale); SNA = sella-nasion-A point angle; SNB = sella-nasion-B point angle; ANB = A point-nasion-B point angle; Na Perp = nasion perpendicular; Pg = pogonion; Gn = gnathion; FH = Frankfurt horizontale; Go = gonion; PP = palatal plane; MP = mandibular plane; Art = articulare; Me = menton; ANS = anterior nasal spine; Co = condylion; Mx/Md dif = maxillomandibular difference; PFH = posterior facial height; AFH = anterior facial height; OCP = occlusal plane; U1 = incisal edge of the maxillary incisor; L1 = incisal edge of the mandibular incisor; U6 = maxillary first molar; L6 = mandibular first molar; NF = nasal floor; Sn = subnasale; ULA = upper lip anterior; LLA = lower lip anterior; A’ = soft tissue subspinale; B’ = soft tissue supramentale; Pg’ = soft tissue pogonion.