Comparative effect of the Myobrace appliance versus traditional functional appliances in treating a class II malocclusion: a systematic review and meta-analysis

Figure 1.

Figure 2.

Figure. 3-1.

Figure 4.

Figure 5.

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Number	Article	Reason for exclusion
1	Levrini L, Salone GS, Ramirez-Yanez GO. Pre-Fabricated Myofunctional Appliance for the Treatment of Mild to Moderate Pediatric Obstructive Sleep Apnea: A Preliminary Report. J Clin Pediatr Dent. 2018;42(3):236-9.	Inclusion criterion for control not met
2	Dinkova M. Vertical Control of Overbite in Mixed Dentition by Trainer System. Journal of IMAB - Annual Proceeding (Scientific Papers). 2014;20:648-54.	Inclusion criterion for control not met
3	Levrini L, Persano R, Piantanida S, Carganico A, Deppieri A, Naboni G, et al. The Effects of the Myobrace(®) System on Peripheral Blood Oxygen Saturation (SpO(2)) in Patients with Mixed Dentition with Oral Dysfunction. Dent J (Basel). 2023;11(8).	Inclusion criterion for control not met
4	Alhasyimi AA, Syahfik I. Growth Modification of Developing Class II Division 1 Malocclusion Using Myofunctional Appliances. Case Rep Dent. 2023;2023:8201195.	Case report
5	Rezky Oktaviyani R, Harun A, Wesley K, Iriani F, Nurwahidah A, Sulfina H, et al. Myobrace versus twin block in the treatment of class II malocclusion in Children: A systematic review. Saudi Dent J. 2024;36(5):661-4.	Review article
6	Ahn ES, Kim AH, Shim YS, An SY. Oropharyngeal Airway Three-dimensional Changes after Treatment with Myobrace in Class II Retrognathic Children. Iran J Public Health. 2017;46(2):265-7.	Case report
7	Cheng HW, Ho CT, Kao CT. A useful method to correct early unilateral posterior crossbite. J Dent Sci. 2022;17(3):1401-2.	Case report
8	Aggarwal I, Wadhawan MC, Dhir V, Kumar A. Myobraces: Say No to Traditional Braces. Int J Oral Care Res. 2016;4(1):82-5.	Review article
9	Achmad H, Auliya N. Management of Malocclusion in Children Using Myobrace Appliance: A Systematic Review. F1000Research. 2024;13:53.	Review article
10	Mohammed H, C̈irgić E, Rizk MZ, Vandevska-Radunovic V. Effectiveness of prefabricated myofunctional appliances in the treatment of Class II division 1 malocclusion: a systematic review. Eur J Orthod. 2020;42(2):125-34.	Review article
11	Achmad H, Horax S, Singgih M, Samad R, Sumintarti S, Rieuwpassa I, et al. The effectiveness of myobrace on the treatment of Malocclusion and bad habits in children. Int J Health Sci. 2022:4073-82.	Review article
12	Anastasi G, Dinnella A. Myobrace System: a no-braces approach to malocclusion and a myofunctional therapy device. Webmed Cent Orthod. 2014;5:WMC004492.	Review article
13	Ramirez-Yañez GO, Flutter J, editors. Facial Symmetry Improves After Treating Malocclusions with the Myobrace™ System. Ec Dental Science. 2016; 712.	Inclusion criterion for control not met
14	Rautela M, Aeran H, Dhawan P. Myobrace: From braces to no braces. Guident. 2017;10(9),28.	Case report
15	Elnaili SA, Bushwigeer SS, Alzway AA, editors. Myobrace as an alternative to conventional orthodontics treatment. 2019.	Not a clinical study
16	Wishney M, Darendeliler MA, Dalci O. Myofunctional therapy and prefabricated functional appliances: an overview of the history and evidence. Australian dental journal. 2019;64(2):135-44.	Review article
17	Ahn ES, Kim AH, Shim YS, An SY. Oropharyngeal Airway Three-dimensional Changes after Treatment with Myobrace in Class II Retrognathic Children. Iran. J. Public Health. 2017;46(2):265-7.	Not a clinical study
18	Dinkova M. Vertical control of overbite in mixed dentition by Trainer system. J IMAB. 2014 Oct-Dec;20(5):648-54.	Case report
19	Tripathi NB, Patil SN. Treatment of class II division 1 malocclusion with myofunctional trainer system in early mixed dentition period. The journal of contemporary dental practice. 2011;12(6):497-500.	Case report
20	Uysal T, Yagci A, Kara S, Okkesim S. Influence of pre-orthodontic trainer treatment on the perioral and masticatory muscles in patients with Class II division 1 malocclusion. Eur J Orthod. 2012;34(1):96-101.	Focus on muscle activity
21	Quinzi V, Gallusi G, Carli E, Pepe F, Rastelli E, Tecco S. Elastodontic Devices in Orthodontics: An In-Vitro Study on Mechanical Deformation under Loading. Bioengineering. 2022;9(7).	Focus on material properties
22	Yagci A, Uysal T, Kara S, Okkesim S. The effects of myofunctional appliance treatment on the perioral and masticatory muscles in Class II, Division 1 patients. World J Orthod. 2010;11(2):117-22.	Focus on muscle activity
23	Cheng HW, Ho CT, Kao CT. A useful method to correct early unilateral posterior crossbite. J Dent Sci. 2022;17(3):1401-2.	Case report
24	Dinu S, Buzatu R, Macasoi I, Popa M, Vlad CS, Marcovici I, et al. Toxicological Profile of Biological Environment of Two Elastodontic Devices. Processes. 2021;9(12):2116.	Focus on material properties
25	Satygo EA, Silin AV, Ramirez-Yañez GO. Electromyographic muscular activity improvement in Class II patients treated with the pre-orthodontic trainer. J Clin Pediatr Dent. 2014;38(4):380-4.	Focus on muscle activity
26	Tripathi NB, Patil SN. Treatment of class II division 1 malocclusion with myofunctional trainer system in early mixed dentition period. J Contemp Dent Pract. 2011;12(6):497-500.	Case report
27	Saccomanno S, Antonini G, D’Alatri L, D’Angelantonio M, Fiorita A, Deli R. Patients treated with orthodontic-myofunctional therapeutic protocol. Eur J Paediatr Dent. 2012;13(3):241-3.	Case report
28	Pachori Y, Navlani M, Gaur T, Bhatnagar S. Treatment of skeletal class II division 1 malocclusion with mandibular deficiency using myofunctional appliances in growing individuals. J Indian Soc Pedod Prev Dent. 2012;30(1):56-65.	Case report

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Table A. Search strategy for Medline via PubMed (n=55)
#1	“Myobrace” [Title/Abstract]
#2	“The Trainer System” [Title/Abstract]
#3	“Trainer for Kids” [Title/Abstract]
#4	“T4K”[Title/Abstract]
#5	#1 or #2 or #3 or #4
Table B. Search strategy for EMBASE (n=40)
#1	‘Myobrace’
#2	‘The Trainer System’
#3	‘Trainer for Kids’
#4	‘T4K’
#5	#1 OR #2 OR #3 OR #4
Table C. Search strategy for Web of Science (n=155)
#1	TI: (Myobrace)
#2	TI: (The Trainer System)
#3	TI: (Trainer for Kids)
#4	TI: (T4K)
#5	#1 or #2 or #3 or #4
Table D. Search strategy for CENTRAL (The Cochrane Library) (n=9)
#1	Myobrace:ti,ab,kw
#2	“The Trainer System”:ti,ab,kw
#3	“Trainer for Kids”):ti,ab,kw
#4	T4K:ti,ab,kw
#5	#1 or #2 or #3 or #4
Table E. Search strategy for ClinicalTrials.gov (n=30)
#1	Myobrace
#2	“The Trainer System”
#3	“Trainer for Kids”
#4	T4K
#5	#1 OR #2 OR #3 OR #4
Table F. Search strategy for China National Knowledge Infrastructure (n=73)
#1	: Myobrace
#2	: MRC
#3	: T4K
#4	#1 OR #2 OR #3

Characteristics of the 13 included studies

	Study (Author year)	Country	Study design	Sample size	Age (years)	Myobrace group	Compa rison group	Treatment time	Outcomes
									Dentoalveolar	Skeletal	Soft tissue
1	Ramirez-Yañez 200725	USA	NRS	120	8.3 ± 1.0	T4K® (n=60)	No treatment (n = 60)	6 months	U6-6(mm), U3-3(mm), L6-6(mm), L3-3(mm)	N/A	N/A
2	C̈rgić 201530	Sweden	RCT	97	7-14	Myobrace® (n=57)	Activator (n=40)	12 months	Overjet, Overbite	sagittal relation,	lip seal
3	Sun 201821	China	RCT	20	8-11	Myobrace® (n=10)	Activator (n=10)	6 months	L1-NB(mm), L1-NB(°), U1-NA(mm), U1-NA(°), Co-Pg, Overjet, Overbite	SNA, SNB, ANB	N/A
4	Idris 201922	Syria	RCT	60	10.3 ± 1.4	T4K® (n=30)	Activator (n=30)	12-18 months	Overjet, Overbite, Ls to E, Li to E, U1-SN	SNA, SNB, ANB, N-Me, N-ANS, ANS-Me, MP-FH	N/A
5	Elhamouly 202026	Egypt	RCT	20	9-12	T4K® (n=10)	Twin-Block (n=10)	18-24 months	Overjet, U1-FHP, L1-MP, Is-APog(mm), li-NB(mm), U6-PL.P (mm), L6-MP(mm), mi-PtV(mm), UAP(mm), LAP(mm)	N/A	N/A
6	Hanoun 202023	America	RCT	43	11-14	T4F (n=21)	Twin-Block (n=22)	10-12 months	Overjet, Overbite, Sv_is (mm), Sv_ii (mm), Sv_ii (mm)	SNA, SNB, ANB, Sn-Man(°), MMPA(°)	N/A
7	Ji 202027	China	RCT	25	9.1 ± 1.3	Myobrace® (n=13)	Twin-Block (n=12)	12 months	U1-SN(mm), U1-SN(°), L1-NB(mm), L1-NB(°), L1-MP, Overjet, Overbite	SNA, SNB, ANB, FH-MP, NP-FH	N/A
8	Xie 202019	China	RCT	22	9.7 ± 1.3	Myobrace® (n=11)	Twin-Block (n=11)	12 months	U1-NA mm), U1-NA (°), L1-NB (mm), L1-NB (°), Po-NB (mm),	SNA, SNB, ANB, FMA, FH-MP, Y-axis (°), NP-FH (°), SN-FH (°)	N/A
9	Chen 202128	China	NRS	40	12.43 ± 0.76	Myobrace® (n=20)	Twin-Block (n=20)	6 months	U1-SN, L1-MP	SNA, SNB, ANB, FH-MP, Y axis, NP-FH	CmSnLs( ° ), A’Ls-FH(°), IMsLs-FH(°), IMsLs-FH(°), LiB’Pg’(°), GSnPg’(°)
10	Johnson 202131	UAE	RCT	20	10.40 ± 1.89	Myobrace® (n=10)	Twin-Block (n=10]	9 months	U1-NA (mm), U1-NA (°), L1-NB (mm), L1-NB (°), U1-SN, Overjet, Overbite, U6-6(mm), L6-6(mm)	SNA, SNB, ANB, NA-Pog, PP-MP, Ar-Gn, Go-Ar, Go-Me	N/A
11	Habumugisha 202224	China	NRS	145	7.41 ± 1.21	Myobrace® (n=75)	No treatment (n=70)	12 months	U1-NA (°), L1-NB(°), Overjet, Overbite, U6-6(mm), U3-3(mm), L6-6(mm), L3-3(mm)	SNA, SNB, ANB, FH-MP, SN-GoGn, S-Go	N/A
12	Çoban Büyükbayraktar and Camci (2023)13	Turkey	NRS	36	12.14 ± 1.23	Myobrace® (n=18)	Twin-Block (i=18)	12-16 months	U1-NA (mm), U1-NA (°), L1-NB (mm), L1-NB (°), U1-SN (°), Overjet, Overbite, Pg-NB (mm), FMA (°)	SNA, SNB, ANB, FMA (°), FMIA (°),	Upper lip-E line, Lower lip-E line
13	Madian 202312	Egypt	RCT	26	9 – 12	Myobrace® (n = 13)	Twin-Block (n=13)	16 months	N/A	SNA, SNB, ANB, Wits appraisal, FMA	phaiyngeal airway area

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Author(s):
Date: 2024-08-04
Question: MRC vs TB for [Malocclusion]
Settings:
Bibliography:. [Myobrace] for [Malocclusion], Cochrane Database of Systematic Reviews [Year], Issue [Issue].
Quality assessment							No of patients			Effect
No of studies	Design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	MRC	TB	Relative (95% Cl)	Absolute	Quality	Importance
SNA (Better indicated by lower values)
7	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	106	101	–	MD 0.36 higher (0.06 to 0.66 higher)	⊕⊕⊕⊕○ MODE RATE
SNB (Better indicated by lower values)
7	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	101	101	–	MD 0.38 lower (1.36 lower to 0.59 higher)	⊕○○○ VERY LOW
ANB (Better indicated by lower values)
6	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	90	90	–	MD 0.19 higher (0.86 lower to 1.24 higher)	⊕○○○ VERY LOW
FMA(°) (Better indicated by lower values)
5	randomised trials	no serious risk of bias	serious3	no serious indirectness	serious1	none	75	74	–	MD 0.26 higher (1.19 lower to 1.7 higher)	⊕⊕○○ LOW
Ar-Go(mm) (Better indicated by lower values)
2	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	23	22	–	MD 1.51 lower (2.87 to 0.15 lower)	⊕⊕⊕○ MODERATE
Go-Me(mm) (Better indicated by lower values)
2	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	23	22	–	MD 2.19 higher (0.37 to 4.02 higher)	⊕⊕⊕○ MODERATE
Y-axis(°) (Better indicated by lower values)
2	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	31	31	–	MD 2.33 higher (5.58 lower to 10.24 higher)	⊕○○○ VERY LOW
Overbite(mm) (Better indicated by lower values)
3	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	41	40	–	MD 0.83 higher (0.1 to 1.55 higher)	⊕⊕⊕○ MODERATE
Overjet(mm) (Better indicated by lower values)
5	randomised trials	no serious risk of bias	serious3	no serious indirectness	serious1	none	65	65	–	MD 1.45 higher (0.1 to 2.79 higher)	⊕⊕○○ LOW
U1-SN(°) (Better indicated by lower values)
5	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	72	71	–	MD 0.29 lower (5.94 lower to 5.36 higher)	⊕○○○ VERY LOW
U1-NA(°) (Better indicated by lower values)
4	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	52	51	–	MD 0.3 higher (3.96 lower to 4.55 higher)	⊕○○○ VERY LOW
U1-NA(mm) (Better indicated by lower values)
4	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	52	51	–	MD 0.3 higher (0.64 lower to 1.24 higher)	⊕⊕⊕○ MODE RATE
Ll-NB(mm) (Better indicated by lower values)
4	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	52	51	–	MD 0.34 higher (1.1 lower to 1.78 higher)	⊕○○○ VERY LOW
L1-MP(°) (Better indicated by lower values)
6	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	80	79	–	MD 1.79 higher (1.2 lower to 4.77 higher)	⊕○○○ VERY LOW
L1-NB(°) (Better indicated by lower values)
4	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	52	51	–	MD 3.64 higher (3.05 lower to 10.32 higher)	⊕○○○ VERY LOW
SNA(°) (Better indicated by lower values)
2	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	40	40	–	MD 0.03 higher (0.55 lower to 0.61 higher)	⊕⊕⊕○ MODERATE
SNB(°) (Better indicated by lower values)
2	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	40	40	–	MD 0.86 lower (1.51 to 0.21 lower)	⊕⊕⊕○ MODERATE
ANB(°) (Better indicated by lower values)
2	randomised trials	no serious risk of bias	very serious2	no serious indirectness	serious1	none	40	40	–	MD 0.32 higher (1.23 lower to 1.87 higher)	⊕○○○ VERY LOW
U1-SN(°) (Better indicated by lower values)
2	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	40	40	–	MD 0.24 higher (2.18 lower to 2.67 higher)	⊕⊕⊕○ MODERATE
Overjet (Better indicated by lower values)
2	randomised trials	no serious risk of bias	no serious inconsistency	no serious indirectness	serious1	none	40	40	–	MD 0.51 higher (0.25 lower to 1.27 higher)	⊕⊕⊕○ MODERATE
U3-3(mm) (Better indicated by lower values)
2	observational studies	no serious risk of bias	very serious1	no serious indirectness	serious2	none	135	130	–	MD 1.19 higher (0 to 2.37 higher)	⊕○○○ VERY LOW
U6-6(mm) (Better indicated by lower values)
2	observational studies	no serious risk of bias	very serious1	no serious indirectness	serious2	none	135	130	–	MD 0.86 higher (0.3 lower to 2.01 higher)	⊕○○○ VERY LOW
L3-3(mm) (Better indicated by lower values)
2	observational studies	no serious risk of bias	no serious inconsistency	no serious indirectness	serious2	none	135	130	–	MD 0.1 lower (0.26 lower to 0.06 higher)	⊕○○○ VERY LOW
L6-6(mm) (Better indicated by lower values)
2	observational studies	no serious risk of bias	very serious1	no serious indirectness	serious2	none	135	130	–	MD 0.7 higher (0.71 lower to 2.11 higher)	⊕○○○○ VERY LOW

Summary of risk bias of Non-Randomized Study (NRS) included in the study based on Methodological Index for Non-Randomized Studies (MINORS) scores (0-8 points: low quality; 9-16 points: medium quality; 17-24 points: high quality)

Assessment criteria	Ramirez-Yañez (2007)25	Chen (2021)28	Habumugisha (2022)24	Çoban Büyükbayraktar and Camcı (2023)13
Clear research objectives	2	2	2	2
Continuity of inclusion of patients	2	2	2	2
Expected data collection	2	2	2	2
Outcome indicators reflect appropriately research purpose	2	2	2	2
Outcome measure objectivity	0	1	2	2
Whether the follow-up time was sufficient	2	2	2	2
The rate of lost to follow-up	0	0	0	2
Whether to estimate the sample size	0	0	1	2
Whether the control group was appropriate	2	2	2	2
Whether the control group is synchronized	0	0	2	0
Intergroup baseline	1	0	2	0
Reliability of data statistics	2	2	2	2
Total	15	15	21	20
Quality level	Medium	Medium	High	High

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Item	Authors’ judgment	Description
Ramirez-Yañez 200725 (NRS)
Aim of the study clear	2	Comments: The author gives a clear research purpose
Inclusion of consecutive patients	2	Comment: Patients who met the inclusion criteria were included during the study period
Prospective collection of data	2	Comments: The authors collected the indicators set out in the research plan
Endpoints appropriate to the aim of the study	2	Comments: The bone and tooth measurements in the outcome measures appropriately reflect the purpose of the study
Unbiased assessment of the study endpoint	0	Comments: The evaluation process of outcome indicators is not described
Follow-up period appropriate to the aim of the study	2	Comments: Patients in both groups were treated long enough, with the total duration of treatment lasting 1.3 ± 0.5 months
loss to follow-up less than 5%	0	Comments: As a retrospective study, no loss of follow-up was involved
Prospective calculation of the study size	0	Comment: The author did not estimate the sample size
An adequate control group	2	Comments: The setting of the control group fits the purpose of the study
Contemporary groups	0	Comments: As a retrospective study, the experimental group and the control group were not conducted at the same time
Baseline equivalence of groups	1	Comment: Before the experiment, the authors compared the experimental group with the control group, but did not give detailed data. Quote: “Thus, each patient in the treated group had a matched control from normative data with respect to age, sex and observation period.”
Adequate statistical analyses	2	Comment: The statistics match the type of study
Total	15	Medium
C̈irgić 201530 (RCT)
Random sequence generation	Unclear	Comment: Insufficient information to judge.
Allocation concealment	low	Quote: “ An informed written consent was obtained from the parents and randomization was performed by lottery.”
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	Unclear	Comment: Insufficient information to judge.
Incomplete outcome data addressed	low	Comments: Although there were missing data, the missing data was similar in the experimental group and the control group, and the missing amount was small enough to affect the final results.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.
Sun 201821 (RCT)
Random sequence generation	Unclear	Comment: Insufficient information to judge.
Allocation concealment	Unclear	Comment: Insufficient information to judge.
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	Unclear	Comment: Insufficient information to judge.
Incomplete outcome data addressed	low	Comment: No data missing
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	High	Comments: The sample size was too small, only 20 cases, so other bias was considered high.
Idris 201922 (RCT)
Random sequence generation	low	Quote: “Sixty participants were selected randomly out of the 188 possible candidates using a computer-generated list of random numbers with the aid of SPSS.”
Allocation concealment	low	Quote: “Allocation concealment was performed using opaque sealed envelopes which contained the assigned group for each patient and were not opened till the onset of the trial.”
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	Unclear	Comment: Insufficient information to judge.
Incomplete outcome data addressed	low	Comments: Although there were missing data, the missing data was similar in the experimental group and the control group, and the missing amount was small enough to affect the final results.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.
Elhamouly 202026 (RCT)
Random sequence generation	low	Quote: “The twenty children were randomly assigned in a 1:1 ratio using a computer-generated list of random numbers to one of the two groups.”
Allocation concealment	low	Quote: “An opaque envelope that was opened after seating the participant was used for allocation.”
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	low	Quote: “Two outcome assessors were blind to the appliance used during their evaluations of the X rays and the study models. Additionally, the statistician was blind to the appliances used in the group analysis.”
Incomplete outcome data addressed	High	Comments: There were two patients lost to follow-up in the experimental group and the control group, which reached 20% of the total number of cases.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.
Hanoun 202023 (RCT)
Random sequence generation	low	Quote: “The prospective parallel design study involved a simple randomization using an online randomization tool.”
Allocation concealment	Unclear	Comment: Insufficient information to judge.
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	low	Quote: “The radiographs were re-coded so that the grouping and any identity were obscured to the investigators.”
Incomplete outcome data addressed	low	Comments: No subjects dropped out and data was missing.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.
Ji 202027 (RCT)
Random sequence generation	Unclear	Comment: Insufficient information to judge.
Allocation concealment	Unclear	Comment: Insufficient information to judge.
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	Unclear	Comment: Insufficient information to judge
Incomplete outcome data addressed	low	Comment: No data missing.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.
Xie 202019 (RCT)
Random sequence generation	Unclear	Comment: Insufficient information to judge.
Allocation concealment	Unclear	Comment: Insufficient information to judge.
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	Unclear	Comment: Insufficient information to judge.
Incomplete outcome data addressed	low	Comment: No data missing.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.
Chen 202128 (NRS)
Aim of the study clear	2	Comments: The author gives a clear research purpose
Inclusion of consecutive patients	2	Comment: Patients who met the inclusion criteria were included during the study period
Prospective collection of data	2	Comments: The authors collected the indicators set out in the research plan
Endpoints appropriate to the aim of the study	2	Comments: The bone and tooth measurements in the outcome measures appropriately reflect the purpose of the study
Unbiased assessment of the study endpoint	1	Comments: Measured and evaluated by the author alone, which is too subjective.
Follow-up period appropriate to the aim of the study	2	Comments: The total duration of treatment in both groups lasted 10 to 12 months
Loss to follow-up less than 5%	0	Comments: As a retrospective study, no loss of follow-up was involved
Prospective calculation of the study size	0	Comment: The author did not estimate the sample size
An adequate control group	2	Comments: The setting of the control group fits the purpose of the study
Contemporary groups	0	Comments: As a retrospective study, the experimental group and the control group were not conducted at the same time
Baseline equivalence of groups	0	Comments: The authors did not describe the differences between the two groups before the trial began
Adequate statistical analyses	2	Comment: The statistics match the type of study
Total	15	Medium
Johnson 202131 (RCT)
Random sequence generation	Unclear	Comment: Insufficient information to judge.
Allocation concealment	Unclear	Comment: Insufficient information to judge.
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	Unclear	Comment: Insufficient information to judge.
Incomplete outcome data addressed	low	Comment: No data missing.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.
Habumugisha 202224 (NRS)
Aim of the study clear	2	Comments: The author gives a clear research purpose
Inclusion of consecutive patients	2	Comment: Patients who met the inclusion criteria were included during the study period
Prospective collection of data	2	Comments: The authors collected the indicators set out in the research plan
Endpoints appropriate to the aim of the study	2	Comments: The bone and tooth measurements in the outcome measures appropriately reflect the purpose of the study
Unbiased assessment of the study endpoint	2	The cephalometric radiographs were analyzed by a calibrated investigator with Dolphin 11.5 The investigator was blinded to the information of patients. The landmarks of cephalometric radiographs are shown in Figure 2.
Ramirez-Yañez 200725 (NRS)
Follow-up period appropriate to the aim of the study	2	Comment: Follow-up time is enough Quote: “Our study lasted for 13.0 ± 1.1 months.”
loss to follow-up less than 5%	0	Comment: The study involved 224 patients and was completed by 204 patients. The loss of follow-up rate is higher than 5 percent.
Prospective calculation of the study size	1	Comment: The author mentions an estimate of sample size, but the information is insufficient
An adequate control group	2	Comments: The setting of the control group fits the purpose of the study
Contemporary groups	2	Comments: Control group and experimental group were conducted at the same time.
Baseline equivalence of groups	2	Quote: “There were no statistical differences in the average age, sex, ANB°, and SNA° among the three groups (P > 0.05).”
Adequate statistical analyses	2	Comment: The statistics match the type of study
Total	21	High
Çoban Büyükbayraktar and Camcı (2023)13 (NRS)
Aim of the study clear	2	Comment: The author gives a clear research purpose
Inclusion of consecutive patients	2	Comment: Patients who met the inclusion criteria were included during the study period
Prospective collection of data	2	Comment: The authors collected the indicators set out in the research plan
Endpoints appropriate to the aim of the study	2	Comment: The authors collected the indicators set out in the research plan
Unbiased assessment of the study endpoint	2	Quote:”A single investigator (H.C.) performed measure ments without knowing which group each x-ray belonged to.”
Follow-up period appropriate to the aim of the study	2	Comment: Follow-up time is enough Quote: “analyze the changes after one year of treatment.”
loss to follow-up less than 5%	2	Comment: There were no missing data according to the results
Prospective calculation of the study size	2	Quote:”Te sample size calculation using the G Power software revealed that at least 32 patients were required (efect size=0.8, α =0.05, and 1–β =0.90)”
An adequate control group	2	Comments: The setting of the control group fits the purpose of the study
Contemporary groups	0	Comment: As a retrospective study, the experimental group and the control group were not conducted at the same time
Baseline equivalence of groups	0	Comment: The authors did not describe the differences between the two groups before the trial began
Adequate statistical analyses	2	Comment: The statistics match the type of study
Total	20	High
Madian 202312 (RCT)
Random sequence generation	low	Quote: “Twenty-six children were randomly assigned in a 1:1 ratio using a computer-generated list of random numbers to one of the two groups.”
Allocation concealment	low	Quote: “When a patient was deemed as eligible for enrollment, the patient was assigned to a treatment group using opaque and sealed envelopes containing the allocation number.”
Blinding of participants and personnel	High	Comment: Blinding of participants and personnel is impossible.
Blinding of outcome assessment	low	Quote: “The researcher and the statistician who evaluated the data were blinded.”
Incomplete outcome data addressed	low	Comment: No data missing.
Free of selective reporting	low	Comments: The indicators selected by the authors for observation before the experiment were fully reported during the experiment.
Other Bias	low	Comments: No other bias was detected.