Early class III protraction facemask treatment reduces the need for orthognathic surgery: a multi-centre, two-arm parallel randomized, controlled trial

Figures & data

Figure 1 Trial profile

Table 1 Baseline characteristics of patients in the CG and PFG.

	CG Mean (SD)	PFG Mean (SD)
Age (years)	9.0 (0.8)	8.7 (0.9)
Gender n (%)
Male	16 (47.1)	18 (52.9)
Female	22 (56.4)	17 (43.6)
SNA	78.6 (2.5)	78.5 (3.1)
SNB	81.1 (2.8)	80.5 (3.2)
ANB	−2.5 (2.0)	−2.0 (1.9)
Sn/MxP	8.0 (3.0)	8.4 (3.6)
MMangle	26.0 (5.0)	26.2 (4.3)
%LFH	54.3 (2.6)	54.8 (1.8)
UI/MxP	110.5 (9.6)	109.1 (5.5)
LI/MdP	87.6 (7.2)	87.0 (6.5)
Inter-incisal angle	136.4 (11.6)	138.5 (9.4)
Overjet (mm)	−2.3 (1.1)	−2.2 (1.3)
Weighted PAR	32.5 (10.2)	33.6 (8.6)
Forward mandibular displacement on closure %	52.6	52.9
Piers Harris self-esteem total mean score (SD)	49.5 (8.1)	51.4 (5.8)
OASIS mean score (SD)	21.2 (7.5)	20.6 (6.7)

Table 2 Reliability [Limits of agreement and Intra-class Correlation Coefficients (ICC)].

	Mean difference	Limits of agreement	ICC
SNA	0.3	1.1, −0.5	0.99
SNB	0.2	1.0, −0.6	0.99
ANB	0.1	1.1, −0.9	0.95
Maxillary plane rotation	0.2	−4.0, 4.4	0.81
Occlusal plane rotation	0.1	−6.9, 7.1	0.72
MM angle	0.0	0.6, −0.6	1.00
Percentage lower face height	0.3	1.9, −1.3	0.95
Upper incisor/ maxillary plane	0.0	1.0, −1.0	1.00
Lower incisor/mandibular plane	−0.1	0.5, −0.7	1.00
Inter-incisal angle	0.2	1.2, −0.8	1.00
Overjet	0.2	1.4, −1.0	0.98
Weighted PAR	0.1	3.9, −3.7	0.98

Table 3 Receipt of orthodontic treatment, or extractions alone, age 12 years.

	Control group (CG)	Protraction facemask group (PFG)
No orthodontic treatment	16	19
Upper fixed appliance non-extraction	5	5
Upper fixed appliance with extractions	7	7
Upper or lower arch extraction only	4	2

Table 4 Statistically significant effects of PFG compared with the CG at DC2 and those maintained at DC3 (in bold).

	PFG DC2 (degrees)	PFG DC3 (degrees)
SNA	1.1	0.7
SNB	−1.5	−0.7
ANB	2.6	1.4
Maxilla rotation	4.4 down and backwards	4.1 down and backwards
Functional occlusal plane
Rotation	4.5 up and forwards	2.8 up and forwards
MM angle	1.6	0.4
L/MdP	−3.7	−0.8
Overjet (mm)	4.1	2.5
% weighted PAR (difference between PFG improvement and CG worsening)	40.8	29.4

Table 5 Cephalometric changes DC1 to DC4.

	DC4 → DC1	DC4 → DC1	Regression coefficient (SE) 95% CI	P value
	Mean change (SD) CG	Mean change (SD) PFG
SNA	0.9 (2.9)	0.6 (4.3)	0.34 (0.90) −1.45 to 2.14	0.70
SNB	1.6 (2.3)	0.6 (4.3)	1.01 (0.87) −0.73 to 2.74	0.25
ANB	−0.7 (2.6)	0.0 (3.3)	−0.87 (0.72) −2.30 to 0.56	0.23
Sn/MxP	0.1 (2.5)	0.2 (4.4)	−0.30 (0.84) −1.98 to 1.39	0.73
Maxillary rotational change	5.5 (3.5)*	2.7 (2.2)**	8.24 (0.75) 6.73 to 9.75	<0.001
Mandibular rotational change	5.4 (3.0)*	1.4 (2.7)**	6.72 (0.73) 5.27 to 8.18	<0.001
MMangle	−1.0 (3.6)	−0.7 (4.4)	−0.29 (0.97) −2.23 to 1.65	0.77
%LFH	1.2 (1.8)	−0.1 (2.7)	1.07 (0.50) 0.06 to 2.07	0.04
UI/MxP	6.8 (10.2)	7.1 (7.4)	0.79 (1.63) −2.46 to 4.04	0.63
LI/MdP	−2.7 (5.2)	−0.4 (5.3)	−2.14 (1.23) −4.59 to 0.31	0.09
Inter-incisal angle	−3.1 (11.4)	−6.0 (8.0)	2.01 (2.17) −2.33 to 6.34	0.36
Overjet (mm)	1.7 (3.0)	3.0 (3.0)	−1.16 (0.76) −2.69 to 0.37	0.14
Weighted PAR	10.2% improved	27.7% improved	4.36 (3.76) −3.17 to 11.88	0.22
Piers Harris	2.1 (8.1)	1.8 (7.8)	−1.26 (1.78) −4.84 to 2.32	0.48
OASIS	−1.3 (10.3)	−3.5 (10.7)	2.13 (2.64) −3.16 to 7.41	0.42

*Rotation upwards and forwards/anti-clockwise.

**Rotation downwards and backwards/ clockwise.

Bold P value denotes statistically significant differences between PG and CG.

CG = Control Group.

PFG = Protraction Facemask Group.

Table 6 Forward mandibular displacement on closure at DC1 and DC4.

	DC1 (n)		DC4 (n)
	No	Yes	No	Yes
CG	14	18	21	11
PFG	15	18	30	3