Introduction
Material and methods
Patients
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Full permanent dentition (except for third molars),
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No tooth loss during treatment,
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No previous orthodontic treatment,
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Pre-treatment ANB ≥ 4° and distal occlusion of at least ½ cusp width,
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Caucasian origin of patients (visual inspection).
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Craniofacial anomalies,
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Loss or agenesis of permanent teeth (except for third molars),
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Extraction therapy.
FFA treatment protocol
Lateral cephalograms
Measurement | I. Skeletal and dental effects |
Maxilla sagittal (mm) | |
N-ANS on FH | Anterior position of the maxillary base: linear distance between the junction of the frontal bone and nasal bone at the nasofrontal suture (Nasion (N)) and the most anterior point of the bony floor of the nose at the tip of the anterior nasal spine (ANS) projected onto the Frankfurt Horizontal (FH) |
Ba-PNS | Posterior position of the maxillary base: linear distance between the anterior margin of the foramen magnum (Basion (Ba)) and most posterior point of the bony floor of the nose at the tip of the posterior nasal spine (PNS) |
Maxilla vertical (mm) | |
N-ANS | Linear distance between landmarks Nasion (N) and anterior nasal spine (ANS) |
N-PNS | Linear distance between landmarks Nasion (N) and posterior nasal spine (PNS) |
Mandible sagittal (mm) | |
N-Pog on FH | Anterior position of the mandibular base: linear distance between landmark Nasion (N) and most anterior point of the bony chin (Pog) projected onto the Frankfurt Horizontal (FH) |
Co(dorsal)−PTV | Position of the dorsal condyle margin: linear distance between the most posterior point of the mandibular condyle (Co(dorsal)) and pterygoid vertical (PTV) |
Mandible vertical (mm) | |
S-Co(superior) | Linear distance between the Sella turcica’s midpoint (Sella, (S)) and condyle’s superior margin (Co(superior)) |
S-Go | Linear distance between landmark Sella (S) and intersection of the ramus tangent and corpus tangent (Go) |
N-Me | Linear distance between landmark Nasion (N) and most inferior point of the bony chin (Me) |
Dental horizontal (mm) | |
U1(incisal)-PTV | Linear distance between the incisal tip of the upper central incisor (U1(incisal)) and PTV† |
L1(incisal)-PTV | Linear distance between the incisal tip of the lower central incisor (L1(incisal)) and PTV† |
U6(dorsal)-PTV | Linear distance between the most distal point of upper first molar’s tooth crown (U6(dorsal)) and PTV† |
L6(dorsal)-PTV | Linear distance between the most distal point of lower first molar’s tooth crown (L6(dorsal)) and PTV† |
Overjet | Distance between the incisal tips of the lower (L1(incisal)) and upper central incisors (U1(incisal)) measured along the occlusal plane (OP) |
Overbite | Distance between the tips of the lower (L1(incisal)) and upper central incisors (U1(incisal)) measured perpendicular to the occlusal plane (OP) |
II. Side effects on occlusal plane, gonial angle, and lower incisor inclination | |
Mandible diagonal (mm) | |
Co(dorsal)-Pog | Linear distance between landmarks Co(dorsal) and Pog |
Co(superior)-Gn | Linear distance between the most superior point of the mandibular condyle (Co(superior)) and most anterior, inferior point on the mandibular symphysis (Gnathion, (Gn)) |
Mandible angular (°) | |
Ar-Go-Me | Gonial angle: angle between intersection of the posterior border of the neck of the condyle with the cranial base (Ar) and landmarks gonion (Go), and menton (Me) |
Co(dorsal)-Go-Pog | Modified gonial angle: angle between the landmarks posterior condylar margin (Co(dorsal)), gonion (Go), and pogonion (Pog) landmarks |
Cant of occlusal plane (°) | |
SN/OP | Angle between the anterior cranial base (SN) and the occlusal plane (OP) |
Dental angular (°) | |
U1/SN | Angle between the longitudinal axis of the upper central incisor (U1) and anterior cranial base (SN) |
U1/PP | Angle between the longitudinal axis of the upper central incisor (U1) and palatal plane (PP) |
L1/MP | Angle between the longitudinal axis of the lower central incisor (L1) and mandibular plane (MP) |
U1/L1 | Interincisal angle: angle formed by the intersection of the longitudinal axis of the upper central incisor (U1) with the longitudinal axis of the lower central incisor (L1) |
U6/SN | Angle between the longitudinal axis of the upper first molar (U6) and anterior cranial base (SN) |
L6/MP | Angle between the longitudinal axis of the lower first molar (L6) and mandibular plane (MP) |
Statistical analysis
Results
Fixed functional appliances—hypodivergent patients | |||||||
---|---|---|---|---|---|---|---|
Measurement | T1 (M ± SD) 95% CI (LB, UB) | T2 (M ± SD) 95% CI (LB, UB) | ∆T2 − T1 (M ± SD) 95% CI (LB, UB) | Control (M ± SD) 95% CI (LB, UB) | Net (M ± SD) 95% CI (LB, UB) | Net p-value (intra) | Net p-value (inter) |
Maxilla sagittal (mm) | |||||||
N-ANS on FH | 4.64 ± 1.93 3.83, 5.45 | 4.81 ± 2.97 3.56, 6.07 | 0.17 ± 2.36 -0.82, 1.17 | 0.26 ± 0.48 0.06, 0.46 | −0.09 ± 2.38 −1.09, 0.92 | 0.860 NS | 0.877 NS |
Ba-PNS | 45.18 ± 2.83 43.98, 46.37 | 46.00 ± 2.71 44.86, 47.14 | 0.82 ± 2.23 −0.12, 1.77 | 0.57 ± 0.70 0.28, 0.87 | 0.25 ± 2.25 −0.70, 1.20 | 0.586 NS | 0.803 NS |
Maxilla vertical (mm) | |||||||
N-ANS | 49.63 ± 4.34 47.80, 51.47 | 51.73 ± 4.05 50.02, 53.44 | 2.10 ± 2.88 0.88, 3.31 | 1.09 ± 1.13 0.61, 1.57 | 1.01 ± 2.46 −0.03, 2.05 | 0.057 NS | 0.675 NS |
N-PNS | 69.16 ± 4.56 67.23, 71.09 | 71.28 ± 4.53 69.36, 73.19 | 2.12 ± 3.25 0.74, 3.49 | 1.18 ± 1.48 0.56, 1.81 | 0.93 ± 3.07 −0.36, 2.23 | 0.150 NS | 0.667 NS |
Mandible sagittal (mm) | |||||||
N-Pog on FH | −6.71 ± 5.43 −9.00, −4.42 | −5.47 ± 6.31 −8.13, −2.80 | 1.24 ± 4.79 −0.78, 3.27 | 1.10 ± 1.16 0.61, 1.59 | 0.15 ± 4.73 −1.85, 2.14 | 0.881 NS | 0.696 NS |
Co(dorsal)−PTV | 34.90 ± 2.45 33.86, 35.93 | 34.87 ± 3.10 33.56, 36.18 | −0.03 ± 2.61 −1.13, 1.08 | 0.51 ± 0.59 0.26, 0.75 | −0.53 ± 2.67 −1.66, 0.60 | 0.340 NS | 0.229 NS |
Mandible vertical (mm) | |||||||
S-Co(superior) | 20.43 ± 2.30 19.46, 21.40 | 21.75 ± 3.10 20.44, 23.06 | 1.32 ± 2.45 0.29, 2.36 | 0.51 ± 0.61 0.25, 0.77 | 0.81 ± 2.45 −0.22, 1.84 | 0.119 NS | 0.319 NS |
S-Go | 74.30 ± 6.82 71.42, 77.18 | 78.66 ± 6.91 75.74, 81.57 | 4.35 ± 3.06 3.06, 5.64 | 2.11 ± 2.19 1.18, 3.04 | 2.24 ± 2.82 1.06, 3.43 | < 0.001 *** | 0.222 NS |
N-Me | 109.03 ± 7.16 106.01, 112.05 | 113.43 ± 6.97 110.48, 116.37 | 4.40 ± 4.74 2.39, 6.40 | 2.52 ± 2.38 1.52, 3.53 | 1.87 ± 4.22 0.09, 3.65 | 0.040 * | 0.389 NS |
Dental horizontal (mm) | |||||||
U1(incisal)-PTV | 55.83 ± 5.29 53.59, 58.06 | 56.01 ± 3.97 54.34, 57.68 | 0.18 ± 3.82 −1.43, 1.79 | 1.25 ± 1.94 0.43, 2.07 | −1.07 ± 3.94 −2.73, 0.60 | 0.197 NS | 0.464 NS |
L1(incisal)-PTV | 48.65 ± 4.48 46.76, 50.54 | 52.93 ± 4.44 51.06, 54.81 | 4.28 ± 3.08 2.98, 5.58 | 1.24 ± 1.92 0.43, 2.05 | 3.04 ± 2.92 1.81, 4.28 | < 0.001 *** | 0.649 NS |
U6(dorsal)-PTV | 15.56 ± 4.75 13.56, 17.57 | 15.94 ± 3.55 14.44, 17.44 | 0.38 ± 2.79 −0.80, 1.56 | 1.25 ± 1.94 0.43, 2.07 | −0.87 ± 3.12 −2.19, 0.44 | 0.184 NS | 0.597 NS |
L6(dorsal)-PTV | 13.39 ± 4.62 11.44, 15.34 | 16.46 ± 4.08 14.74, 18.19 | 3.07 ± 3.60 1.55, 4.59 | 1.27 ± 1.98 0.44, 2.11 | 1.80 ± 3.47 0.33, 3.27 | 0.018 * | 0.881 NS |
Overjet | 6.94 ± 2.72 5.80, 8.09 | 2.52 ± 1.20 2.02, 3.03 | −4.42 ± 2.40 −5.44, −3.41 | −0.11 ± 0.19 −0.20, −0.03 | −4.31 ± 2.39 −5.32, −3.30 | < 0.001 *** | 0.448 NS |
Overbite | 3.68 ± 1.39 3.09, 4.26 | 1.97 ± 1.07 1.52, 2.42 | −1.70 ± 1.14 −2.18, −1.22 | 0.03 ± 0.26 −0.08, 0.14 | −1.73 ± 1.11 −2.20, −1.26 | < 0.001 *** | 0.004 ** |
Fixed functional appliances—hypodivergent patients | |||||||
---|---|---|---|---|---|---|---|
Measurement | T1 (M ± SD) 95% CI (LB, UB) | T2 (M ± SD) 95% CI (LB, UB) | ∆T2 − T1 (M ± SD) 95% CI (LB, UB) | Control (M ± SD) 95% CI (LB, UB) | Net (M ± SD) 95% CI (LB, UB) | Net p-value (intra) | Net p-value (inter) |
Mandible diagonal (mm) | |||||||
Co(dorsal)-Pog | 104.39 ± 7.47 101.23, 107.55 | 107.84 ± 7.41 104.71, 110.97 | 3.45 ± 3.66 1.90, 5.00 | 1.34 ± 1.32 0.79, 1.90 | 2.11 ± 3.94 0.44, 3.77 | 0.015 * | 0.683 NS |
Co(superior)-Gn | 107.05 ± 7.89 103.72, 110.38 | 111.22 ± 7.58 108.02, 114.42 | 4.17 ± 3.97 2.50, 5.85 | 3.10 ± 3.01 1.83, 4.37 | 1.08 ± 3.21 −0.28, 2.43 | 0.115 NS | 0.708 NS |
Mandible angular (°) | |||||||
Ar-Go-Me | 120.91 ± 7.89 117.58, 124.24 | 120.80 ± 7.56 117.60, 123.99 | −0.12 ± 4.11 −1.85, 1.62 | −0.54 ± 0.40 −0.71, −0.37 | 0.42 ± 4.01 −1.27, 2.12 | 0.609 NS | 0.455 NS |
Co(dorsal)-Go-Pog | 115.32 ± 6.88 112.42, 118.22 | 115.25 ± 7.43 112.11, 118.38 | −0.07 ± 3.45 −1.53, 1.38 | −0.54 ± 0.40 −0.71, −0.37 | 0.47 ± 3.39 −0.97, 1.90 | 0.507 NS | 0.524 NS |
Cant of occlusal plane (°) | |||||||
SN/OP | 17.97 ± 3.81 16.36, 19.58 | 17.32 ± 3.69 15.76, 18.88 | −0.65 ± 2.76 −1.81, 0.51 | −0.99 ± 1.56 −1.65, −0.33 | 0.34 ± 2.91 −0.89, 1.57 | 0.577 NS | 0.156 NS |
Dental angular (°) | |||||||
U1 / SN | 104.65 ± 7.70 101.40, 107.91 | 103.04 ± 6.38 100.35, 105.74 | −1.61 ± 8.23 −5.09, 1.86 | −0.04 ± 0.82 −0.38, 0.31 | −1.58 ± 8.05 −4.98, 1.83 | 0.348 NS | 0.332 NS |
U1 / PP | 113.53 ± 8.06 110.13, 116.93 | 111.11 ± 6.22 108.48, 113.74 | −2.42 ± 7.31 −5.51, 0.67 | 0.02 ± 0.74 −0.29, 0.34 | −2.44 ± 7.06 −5.42, 0.54 | 0.103 NS | 0.339 NS |
L1 / MP | 101.49 ± 6.33 98.82, 104.17 | 107.66 ± 8.32 104.14, 111.17 | 6.17 ± 6.18 3.56, 8.78 | −0.19 ± 0.41 −0.36, −0.01 | 6.35 ± 6.20 3.74, 8.97 | < 0.001 *** | 0.062 NS |
U1/ L1 (interincisal angle) | 124.60 ± 11.87 119.58, 129.61 | 121.08 ± 9.32 117.14, 125.01 | −3.52 ± 7.57 −6.72, −0.33 | 0.80 ± 1.04 0.36, 1.24 | −4.32 ± 7.58 −7.52, −1.12 | 0.010 * | 0.031 * |
U6 / SN | 69.47 ± 6.75 66.62, 72.32 | 70.81 ± 6.85 67.92, 73.71 | 1.34 ± 4.75 −0.66, 3.35 | −0.05 ± 0.82 −0.40, 0.30 | 1.39 ± 4.75 −0.62, 3.40 | 0.348 NS | 0.076 NS |
L6 / MP | 92.72 ± 3.60 91.20, 94.24 | 91.71 ± 6.35 89.03, 94.40 | −1.01 ± 6.57 −3.78, 1.76 | −0.16 ± 0.43 −0.34, 0.02 | −0.85 ± 6.61 −3.64, 1.94 | 0.536 NS | 0.781 NS |
Fixed functional appliances—hyperdivergent patients | |||||||
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Measurement | T1 (M ± SD) 95% CI (LB, UB) | T2 (M ± SD) 95% CI (LB, UB) | ∆T2 − T1 (M ± SD) 95% CI (LB, UB) | Control (M ± SD) 95% CI (LB, UB) | Net (M ± SD) 95% CI (LB, UB) | Net p-value (intra) | Net p-value (inter) |
Maxilla sagittal (mm) | |||||||
N-ANS on FH | 4.11 ± 3.64 2.30, 5.92 | 4.08 ± 3.89 2.14, 6.01 | −0.03 ± 3.31 −1.68, 1.61 | 0.19 ± 0.39 0.00, 0.39 | −0.23 ± 3.48 −1.96, 1.50 | 0.785 NS | 0.877 NS |
Ba-PNS | 44.33 ± 3.97 42.35, 46.30 | 45.54 ± 3.70 43.70, 47.38 | 1.21 ± 2.97 −0.27, 2.68 | 0.76 ± 0.77 0.37, 1.14 | 0.45 ± 2.85 −0.97, 1.87 | 0.512 NS | 0.803 NS |
Maxilla vertical (mm) | |||||||
N-ANS | 51.22 ± 4.41 49.03, 53.41 | 53.40 ± 3.57 51.63, 55.18 | 2.18 ± 2.97 0.70, 3.66 | 1.48 ± 1.35 0.81, 2.15 | 0.70 ± 2.09 −0.34, 1.74 | 0.172 NS | 0.675 NS |
N-PNS | 70.94 ± 6.28 67.82, 74.06 | 73.11 ± 4.78 70.73, 75.49 | 2.17 ± 3.46 0.45, 3.89 | 1.62 ± 1.58 0.83, 2.40 | 0.55 ± 2.46 −0.67, 1.77 | 0.354 NS | 0.667 NS |
Mandible sagittal (mm) | |||||||
N-Pog on FH | −7.82 ± 5.93 −10.77, −4.87 | −7.43 ± 5.35 −10.09, −4.77 | 0.39 ± 4.15 −1.68, 2.45 | 0.83 ± 1.47 0.10, 1.57 | −0.44 ± 4.91 −2.88, 2.00 | 0.706 NS | 0.696 NS |
Co(dorsal)−PTV | 34.17 ± 3.03 32.66, 35.68 | 35.57 ± 4.98 33.09, 38.04 | 1.40 ± 4.68 −0.93, 3.72 | 0.60 ± 0.63 0.29, 0.91 | 0.80 ± 4.34 −1.36, 2.95 | 0.448 NS | 0.229 NS |
Mandible vertical (mm) | |||||||
S-Co(superior) | 20.71 ± 4.44 18.50, 22.91 | 21.54 ± 3.99 19.55, 23.53 | 0.83 ± 2.15 −0.24, 1.90 | 0.73 ± 0.75 0.36, 1.10 | 0.10 ± 1.96 −0.87, 1.08 | 0.828 NS | 0.319 NS |
S-Go | 70.95 ± 7.19 67.38, 74.53 | 74.99 ± 6.65 71.69, 78.30 | 4.04 ± 3.81 2.15, 5.94 | 2.78 ± 2.29 1.64, 3.91 | 1.27 ± 2.06 0.25, 2.29 | 0.018 * | 0.222 NS |
N-Me | 116.43 ± 10.48 111.21, 121.64 | 120.54 ± 8.27 116.42, 124.65 | 4.11 ± 4.82 1.71, 6.51 | 3.32 ± 2.74 1.96, 4.68 | 0.79 ± 3.65 −1.02, 2.60 | 0.371 NS | 0.389 NS |
Dental horizontal (mm) | |||||||
U1(incisal)-PTV | 55.67 ± 2.95 54.20, 57.13 | 55.38 ± 3.73 53.52, 57.23 | −0.29 ± 2.57 −1.57, 0.99 | 1.60 ± 2.16 0.53, 2.67 | −1.89 ± 2.98 −3.37, −0.41 | 0.015 * | 0.464 NS |
L1(incisal)-PTV | 47.97 ± 2.77 46.59, 49.35 | 52.20 ± 3.73 50.35, 54.05 | 4.23 ± 2.72 2.88, 5.59 | 1.60 ± 2.16 0.53, 2.67 | 2.63 ± 2.82 1.23, 4.03 | 0.001 ** | 0.649 NS |
U6(dorsal)-PTV | 14.18 ± 3.67 12.36, 16.01 | 15.09 ± 3.12 13.54, 16.64 | 0.90 ± 2.40 −0.29, 2.10 | 2.38 ± 3.94 0.42, 4.33 | −1.47 ± 4.17 −3.54, 0.60 | 0.152 NS | 0.597 NS |
L6(dorsal)-PTV | 11.97 ± 4.14 9.91, 14.03 | 15.52 ± 3.37 13.84, 17.20 | 3.55 ± 2.91 2.10, 5.00 | 1.60 ± 2.16 0.53, 2.67 | 1.95 ± 2.80 0.56, 3.34 | 0.009 ** | 0.881 NS |
Overjet | 7.48 ± 1.68 6.65, 8.32 | 2.55 ± 1.14 1.98, 3.12 | −4.93 ± 1.58 −5.72, −4.15 | −0.13 ± 0.19 −0.23, −0.04 | −4.80 ± 1.51 −5.55, −4.05 | 0.009 ** | 0.448 NS |
Overbite | 2.01 ± 1.90 1.06, 2.95 | 1.97 ± 1.43 1.26, 2.68 | −0.04 ± 1.81 −0.94, 0.86 | 0.22 ± 0.39 0.02, 0.41 | −0.26 ± 2.03 −1.27, 0.75 | 0.596 NS | 0.004 ** |
Fixed functional appliances—hyperdivergent patients | |||||||
---|---|---|---|---|---|---|---|
Measurement | T1 (M ± SD) 95% CI (LB, UB) | T2 (M ± SD) 95% CI (LB, UB) | ∆T2 − T1 (M ± SD) 95% CI (LB, UB) | Control (M ± SD) 95% CI (LB, UB) | Net (M ± SD) 95% CI (LB, UB) | Net p-value (intra) | Net p-value (inter) |
Mandible diagonal (mm) | |||||||
Co(dorsal)-Pog | 104.76 ± 8.03 100.76, 108.75 | 109.48 ± 6.16 106.41, 112.54 | 4.72 ± 4.95 2.26, 7.18 | 2.09 ± 2.36 0.91, 3.26 | 2.63 ± 4.33 0.48, 4.79 | 0.019 * | 0.683 NS |
Co(superior)-Gn | 107.96 ± 8.71 103.63, 112.30 | 113.08 ± 6.87 109.67, 116.50 | 5.12 ± 4.93 2.67, 7.57 | 3.67 ± 3.05 2.15, 5.19 | 1.45 ± 3.10 −0.09, 2.99 | 0.064 NS | 0.708 NS |
Mandible angular (°) | |||||||
Ar-Go-Me | 128.59 ± 3.88 126.66, 130.53 | 129.51 ± 3.73 127.65, 131.36 | 0.91 ± 4.12 −1.14, 2.96 | −0.48 ± .31 −0.63, −0.32 | 1.39 ± 4.19 −0.70, 3.47 | 0.178 NS | 0.455 NS |
Co(dorsal)-Go-Pog | 122.68 ± 4.51 120.43, 124.92 | 123.37 ± 3.75 121.50, 125.23 | 0.69 ± 3.52 −1.06, 2.44 | −0.48 ± 0.31 −0.63, −0.32 | 1.16 ± 3.60 −0.63, 2.96 | 0.188 NS | 0.524 NS |
Cant of occlusal plane (°) | |||||||
SN/OP | 19.79 ± 4.95 17.33, 22.25 | 20.31 ± 5.28 17.68, 22.93 | 0.52 ± 3.00 −0.98, 2.01 | −1.10 ± 1.25 −1.72, −0.48 | 1.61 ± 2.71 0.26, 2.96 | 0.022 * | 0.156 NS |
Dental angular (°) | |||||||
U1/SN | 104.93 ± 7.84 101.04, 108.83 | 101.17 ± 8.67 96.86, 105.48 | −3.77 ± 6.23 −6.87, −0.67 | 0.04 ± 0.91 −0.41, 0.50 | −3.81 ± 6.13 −6.86, −0.76 | 0.017 * | 0.332 NS |
U1/PP | 113.90 ± 6.85 110.49, 117.31 | 109.68 ± 7.94 105.74, 113.63 | −4.22 ± 5.98 −7.19, −1.24 | 0.20 ± 0.95 −0.27, 0.67 | −4.42 ± 5.80 −7.31, −1.53 | 0.005 ** | 0.339 NS |
L1/MP | 96.20 ± 5.65 93.39, 99.01 | 99.53 ± 5.59 96.75, 102.31 | 3.33 ± 4.44 1.12, 5.54 | 0.35 ± 0.88 −0.09, 0.79 | 2.98 ± 4.75 0.62, 5.34 | 0.016 * | 0.062 NS |
U1/L1 (interincisal angle) | 119.77 ± 7.41 116.08, 123.45 | 121.11 ± 7.88 117.19, 125.03 | 1.34 ± 7.37 −2.32, 5.01 | 0.38 ± 1.06 −0.15, 0.91 | 0.97 ± 7.62 −2.82, 4.75 | 0.597 NS | 0.031 * |
U6/SN | 67.07 ± 4.67 64.74, 69.39 | 65.72 ± 6.75 62.36, 69.08 | −1.34 ± 5.12 −3.89, 1.20 | 0.04 ± 0.91 −0.41, 0.50 | −1.39 ± 5.06 −3.90, 1.13 | 0.261 NS | 0.076 NS |
L6/MP | 97.48 ± 7.29 93.86, 101.11 | 97.52 ± 5.95 94.56, 100.48 | 0.03 ± 5.18 −2.54, 2.61 | 0.35 ± 0.88 −0.09, 0.79 | −0.32 ± 5.31 −2.96, 2.33 | 0.804 NS | 0.781 NS |
Skeletal and dentoalveolar effects
Effects on occlusal plane, gonial angle, and lower incisor inclination
Discussion
Methods
Results
Conclusions
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Dentoalveolar rather than skeletal changes are responsible for improvements of overjet and occlusion in FFA treatment in hypodivergent and hyperdivergent patients.
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Lower incisor protrusion is inevitable and happened more pronounced in hypodivergent patients.
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Lower incisor protrusion may be a contraindication for FFA treatment, especially in hypodivergent patients.
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Effects of FFA treatment upon occlusal plane and gonial angle are negligible.
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A hyperdivergent growth pattern is no contraindication for FFA treatment.